def preprocess_block_objectives(block, idMap=None):
# Get/Create the ComponentMap for the canonical_repn
if not hasattr(block, '_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for objective_data in block.component_data_objects(Objective,
active=True,
descend_into=False):
if objective_data.expr is None:
raise ValueError("No expression has been defined for objective %s"
% (objective_data.name))
try:
objective_data_repn = generate_canonical_repn(objective_data.expr, idMap=idMap)
except Exception:
err = sys.exc_info()[1]
logging.getLogger('pyomo.core').error(
"exception generating a canonical representation for objective %s: %s"
% (objective_data.name, str(err)))
raise
block_canonical_repn[objective_data] = objective_data_repn
def preprocess_block_objectives(block, idMap=None):
# Get/Create the ComponentMap for the canonical_repn
if not hasattr(block, '_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for objective_data in block.component_data_objects(Objective,
active=True,
descend_into=False):
if objective_data.expr is None:
raise ValueError("No expression has been defined for objective %s"
% (objective_data.cname(True)))
try:
objective_data_repn = generate_canonical_repn(objective_data.expr, idMap=idMap)
except Exception:
err = sys.exc_info()[1]
logging.getLogger('pyomo.core').error(
"exception generating a canonical representation for objective %s: %s"
% (objective_data.cname(True), str(err)))
raise
block_canonical_repn[objective_data] = objective_data_repn
def constraint_generator():
for block in all_blocks:
gen_con_canonical_repn = \
getattr(block, "_gen_con_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for constraint_data in block.component_data_objects(
Constraint,
active=True,
sort=sortOrder,
descend_into=False):
if isinstance(constraint_data, LinearCanonicalRepn):
canonical_repn = constraint_data
else:
if gen_con_canonical_repn:
canonical_repn = generate_canonical_repn(
constraint_data.body)
block_canonical_repn[constraint_data] = canonical_repn
else:
canonical_repn = block_canonical_repn[constraint_data]
yield constraint_data, canonical_repn
def evaluate(expr, seconds):
gc.collect()
_clear_expression_pool()
start = time.time()
#
expr_ = expr.clone()
#
stop = time.time()
seconds['clone'] = stop - start
gc.collect()
_clear_expression_pool()
start = time.time()
#
d_ = expr.polynomial_degree()
#
stop = time.time()
seconds['polynomial_degree'] = stop - start
if False:
gc.collect()
_clear_expression_pool()
start = time.time()
#
s_ = expr.to_string()
#
stop = time.time()
seconds['to_string'] = stop - start
gc.collect()
_clear_expression_pool()
start = time.time()
#
s_ = expr.is_constant()
#
stop = time.time()
seconds['is_constant'] = stop - start
gc.collect()
_clear_expression_pool()
start = time.time()
#
s_ = expr.is_fixed()
#
stop = time.time()
seconds['is_fixed'] = stop - start
try:
gc.collect()
_clear_expression_pool()
start = time.time()
#
r_ = generate_canonical_repn(expr)
#
stop = time.time()
seconds['generate_canonical'] = stop - start
except:
seconds['generate_canonical'] = -1
return seconds
def constraint_generator():
for block in all_blocks:
gen_con_canonical_repn = \
getattr(block, "_gen_con_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block, '_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for constraint_data in block.component_data_objects(
Constraint,
active=True,
sort=sortOrder,
descend_into=False):
if isinstance(constraint_data, LinearCanonicalRepn):
canonical_repn = constraint_data
else:
if gen_con_canonical_repn:
canonical_repn = generate_canonical_repn(
constraint_data.body)
block_canonical_repn[
constraint_data] = canonical_repn
else:
canonical_repn = block_canonical_repn[
constraint_data]
yield constraint_data, canonical_repn
def constraint_generator():
for block in all_blocks:
gen_con_canonical_repn = \
getattr(block, "_gen_con_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for constraint_data in block.component_data_objects(
Constraint,
active=True,
sort=sortOrder,
descend_into=False):
if (not constraint_data.has_lb()) and \
(not constraint_data.has_ub()):
assert not constraint_data.equality
continue # non-binding, so skip
if constraint_data._linear_canonical_form:
canonical_repn = constraint_data.canonical_form()
elif isinstance(constraint_data, LinearCanonicalRepn):
canonical_repn = constraint_data
else:
if gen_con_canonical_repn:
canonical_repn = generate_canonical_repn(constraint_data.body)
block_canonical_repn[constraint_data] = canonical_repn
else:
canonical_repn = block_canonical_repn[constraint_data]
yield constraint_data, canonical_repn
def coef_via_pyomo(CostExpression):
canonical_repn = generate_canonical_repn(CostExpression.expr)
cost_coefficients = {}
var_names = {}
for (index, variable) in enumerate(canonical_repn.variables):
variable_id = symbol_map.getSymbol(variable)
cost_coefficients[variable_id] = canonical_repn.linear[index]
var_names[variable_id] = variable.name
return (cost_coefficients, var_names)
def coef_via_pyomo(CostExpression):
canonical_repn = generate_canonical_repn(CostExpression.expr)
cost_coefficients = {}
var_names = {}
for (index, variable) in enumerate(canonical_repn.variables):
variable_id = symbol_map.getSymbol(variable)
cost_coefficients[variable_id] = canonical_repn.linear[index]
var_names[variable_id] = variable.name
return (cost_coefficients, var_names)
def return_c_vector(block, unfixed):
# Note that this function is adapted function collect_linear_terms defined
# in pyomo/repn/collect.py.
from pyutilib.misc import Bunch
from pyomo.core.base import Var, Constraint, Objective, maximize, minimize
from pyomo.repn import generate_canonical_repn
#
# Variables are constraints of block
# Constraints are unfixed variables of block and the parent model.
#
vnames = set()
for (name, data) in block.component_map(Constraint, active=True).items():
vnames.add((name, data.is_indexed()))
cnames = set(unfixed)
for (name, data) in block.component_map(Var, active=True).items():
cnames.add((name, data.is_indexed()))
#
A = {}
b_coef = {}
c_rhs = {}
c_sense = {}
d_sense = None
v_domain = {}
#
# Collect objective
#
for (oname, odata) in block.component_map(Objective, active=True).items():
for ndx in odata:
if odata[ndx].sense == maximize:
o_terms = generate_canonical_repn(-1 * odata[ndx].expr,
compute_values=False)
d_sense = minimize
else:
o_terms = generate_canonical_repn(odata[ndx].expr,
compute_values=False)
d_sense = maximize
for i in range(len(o_terms.variables)):
c_rhs[o_terms.variables[i].parent_component().local_name,
o_terms.variables[i].index()] = o_terms.linear[i]
# Stop after the first objective
break
return c_rhs
def preprocess_constraint(block,
constraint,
idMap=None,
block_canonical_repn=None):
from pyomo.repn.beta.matrix import MatrixConstraint
if isinstance(constraint, MatrixConstraint):
return
# Get/Create the ComponentMap for the canonical_repn
if not hasattr(block, '_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for index, constraint_data in iteritems(constraint):
if not constraint_data.active:
continue
if isinstance(constraint_data, LinearCanonicalRepn):
continue
if constraint_data.body is None:
raise ValueError("No expression has been defined for "
"the body of constraint %s, index=%s" %
(str(constraint.name), str(index)))
# FIXME: This is a huge hack to keep canonical_repn from
# trying to generate representations representations of
# Constraints with Connectors (which will be
# deactivated once they have been expanded
# anyways). This can go away when preprocess is moved
# out of the model.create() phase and into the future
# model validation phase. (ZBF)
ignore_connector = False
if hasattr(constraint_data.body,
"_args") and constraint_data.body._args is not None:
for arg in constraint_data.body._args:
if arg.__class__ is pyomo.core.base.connector.SimpleConnector:
ignore_connector = True
if ignore_connector:
#print "Ignoring",constraint.name,index
continue
try:
canonical_repn = generate_canonical_repn(constraint_data.body,
idMap=idMap)
except Exception:
logging.getLogger('pyomo.core').error \
( "exception generating a canonical representation for constraint %s (index %s)" \
% (str(constraint.name), str(index)) )
raise
block_canonical_repn[constraint_data] = canonical_repn
def _get_expr_from_pyomo_expr(self, expr, max_degree=2):
repn = generate_canonical_repn(expr)
try:
gurobi_expr, referenced_vars = self._get_expr_from_pyomo_repn(repn, max_degree)
except DegreeError as e:
msg = e.args[0]
msg += '\nexpr: {0}'.format(expr)
raise DegreeError(msg)
return gurobi_expr, referenced_vars
def preprocess_constraint(block,
constraint,
idMap=None,
block_canonical_repn=None):
from pyomo.repn.beta.matrix import MatrixConstraint
if isinstance(constraint, MatrixConstraint):
return
# Get/Create the ComponentMap for the canonical_repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for index, constraint_data in iteritems(constraint):
if not constraint_data.active:
continue
if isinstance(constraint_data, LinearCanonicalRepn):
continue
if constraint_data.body is None:
raise ValueError("No expression has been defined for "
"the body of constraint %s, index=%s"
% (str(constraint.name), str(index)))
# FIXME: This is a huge hack to keep canonical_repn from
# trying to generate representations representations of
# Constraints with Connectors (which will be
# deactivated once they have been expanded
# anyways). This can go away when preprocess is moved
# out of the model.create() phase and into the future
# model validation phase. (ZBF)
ignore_connector = False
if hasattr(constraint_data.body,"_args") and constraint_data.body._args is not None:
for arg in constraint_data.body._args:
if arg.__class__ is pyomo.core.base.connector.SimpleConnector:
ignore_connector = True
if ignore_connector:
#print "Ignoring",constraint.name,index
continue
try:
canonical_repn = generate_canonical_repn(constraint_data.body, idMap=idMap)
except Exception:
logging.getLogger('pyomo.core').error \
( "exception generating a canonical representation for constraint %s (index %s)" \
% (str(constraint.name), str(index)) )
raise
block_canonical_repn[constraint_data] = canonical_repn
def _xfrm_bilinearities(self, dual):
"""
Replace bilinear terms in constraints with disjunctions
"""
for (name, data) in dual.component_map(Constraint, active=True).items():
for ndx in data:
con = data[ndx]
degree = con.body.polynomial_degree()
if degree > 2:
raise "RuntimeError: Cannot transform a model with polynomial degree %d" % degree
if degree == 2:
terms = generate_canonical_repn(con.body)
for term in terms:
print("%s %s %s" % (name, ndx, term))
def _xfrm_bilinearities(self, dual):
"""
Replace bilinear terms in constraints with disjunctions
"""
for (name, data) in dual.component_map(Constraint,
active=True).items():
for ndx in data:
con = data[ndx]
degree = con.body.polynomial_degree()
if degree > 2:
raise "RuntimeError: Cannot transform a model with polynomial degree %d" % degree
if degree == 2:
terms = generate_canonical_repn(con.body)
for term in terms:
print("%s %s %s" % (name, ndx, term))
def set_rho_values(ph, scenario_tree, scenario, cost_expr):
"""
Set values for rho for this model, based on linear coefficients in the
provided expression.
"""
# This Rho coefficient is set to 1.0 to implement the CP(1.0) strategy
# that Watson & Woodruff report as a good trade off between convergence
# to the extensive form optimum and number of PH iterations.
rho_coefficient = 1.0
scenario_instance = scenario._instance
symbol_map = scenario_instance._ScenarioTreeSymbolMap
if newPyomo:
standard_repn = generate_standard_repn(cost_expr.expr)
if standard_repn.nonlinear_vars or standard_repn.quadratic_vars:
raise ValueError("This code does not work with nonlinear models.")
else:
standard_repn = generate_canonical_repn(cost_expr.expr)
standard_repn.linear_vars = standard_repn.variables
standard_repn.linear_coefs = standard_repn.linear
cost_coefficients = {}
var_names = {}
for (variable, coef) in \
zip(standard_repn.linear_vars, standard_repn.linear_coefs):
variable_id = symbol_map.getSymbol(variable)
cost_coefficients[variable_id] = coef
var_names[variable_id] = variable.name
return (cost_coefficients, var_names)
for variable_id in cost_coefficients:
set_rho = False
for tree_node in scenario._node_list:
if variable_id in tree_node._standard_variable_ids:
ph.setRhoOneScenario(
tree_node, scenario, variable_id,
cost_coefficients[variable_id] * rho_coefficient)
set_rho = True
break
if not set_rho:
print(
"Warning! Could not find tree node for variable {}; rho not set."
.format(var_names[variable_id]))
def _estimate_M(self, expr, name):
# Calculate a best guess at M
repn = generate_canonical_repn(expr)
M = [0, 0]
if isinstance(repn, LinearCanonicalRepn):
if repn.constant is not None:
for i in (0, 1):
if M[i] is not None:
M[i] += repn.constant
for i, coef in enumerate(repn.linear or []):
var = repn.variables[i]
coef = repn.linear[i]
bounds = (value(var.lb), value(var.ub))
for i in (0, 1):
# reverse the bounds if the coefficient is negative
if coef > 0:
j = i
else:
j = 1 - i
if bounds[i] is not None:
M[j] += value(bounds[i]) * coef
else:
raise GDP_Error(
"Cannot estimate M for "
"expressions with unbounded variables."
"\n\t(found unbounded var %s while processing "
"constraint %s)" % (var.name, name))
else:
raise GDP_Error("Cannot estimate M for nonlinear "
"expressions.\n\t(found while processing "
"constraint %s)" % name)
return tuple(M)
def compile_objective(self, pyomo_instance):
from pyomo.core.base import Objective
from pyomo.repn import canonical_is_constant, LinearCanonicalRepn, canonical_degree
if self._active_cplex_instance is None:
raise RuntimeError("***The CPLEXPersistent solver plugin "
"cannot compile objective - no "
"instance is presently compiled")
cplex_instance = self._active_cplex_instance
cntr = 0
for block in pyomo_instance.block_data_objects(active=True):
gen_obj_canonical_repn = \
getattr(block, "_gen_obj_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for obj_data in block.component_data_objects(Objective,
active=True,
descend_into=False):
cntr += 1
if cntr > 1:
raise ValueError(
"Multiple active objectives found on Pyomo instance '%s'. "
"Solver '%s' will only handle a single active objective" \
% (pyomo_instance.cname(True), self.type))
if obj_data.is_minimizing():
cplex_instance.objective.set_sense(
cplex_instance.objective.sense.minimize)
else:
cplex_instance.objective.set_sense(
cplex_instance.objective.sense.maximize)
cplex_instance.objective.set_name(
self._symbol_map.getSymbol(obj_data,
self._labeler))
if gen_obj_canonical_repn:
obj_repn = generate_canonical_repn(obj_data.expr)
block_canonical_repn[obj_data] = obj_repn
else:
obj_repn = block_canonical_repn[obj_data]
if (isinstance(obj_repn, LinearCanonicalRepn) and \
(obj_repn.linear == None)) or \
canonical_is_constant(obj_repn):
print("Warning: Constant objective detected, replacing "
"with a placeholder to prevent solver failure.")
offset = obj_repn.constant
if offset is None:
offset = 0.0
objective_expression = [("ONE_VAR_CONSTANT",offset)]
cplex_instance.objective.set_linear(objective_expression)
else:
if isinstance(obj_repn, LinearCanonicalRepn):
objective_expression, offset = \
self._encode_constraint_body_linear_specialized(
obj_repn,
self._labeler,
use_variable_names=False,
cplex_variable_name_index_map=self._cplex_variable_ids,
as_pairs=True)
if offset != 0.0:
objective_expression.append((self._cplex_variable_ids["ONE_VAR_CONSTANT"],offset))
cplex_instance.objective.set_linear(objective_expression)
else:
#Linear terms
if 1 in obj_repn:
objective_expression, offset = \
self._encode_constraint_body_linear(
obj_repn,
self._labeler,
as_pairs=True)
if offset != 0.0:
objective_expression.append(("ONE_VAR_CONSTANT",offset))
cplex_instance.objective.set_linear(objective_expression)
#Quadratic terms
if 2 in obj_repn:
self._has_quadratic_objective = True
objective_expression = \
self._encode_constraint_body_quadratic(obj_repn,
self._labeler,
as_triples=True,
is_obj=2.0)
cplex_instance.objective.\
set_quadratic_coefficients(objective_expression)
degree = canonical_degree(obj_repn)
if (degree is None) or (degree > 2):
raise ValueError(
"CPLEXPersistent plugin does not support general nonlinear "
"objective expressions (only linear or quadratic).\n"
"Objective: %s" % (obj_data.cname(True)))
def _print_model_LP(self,
model,
output_file,
solver_capability,
labeler,
output_fixed_variable_bounds=False,
file_determinism=1,
row_order=None,
column_order=None,
skip_trivial_constraints=False,
force_objective_constant=False,
include_all_variable_bounds=False):
symbol_map = SymbolMap()
variable_symbol_map = SymbolMap()
# NOTE: we use createSymbol instead of getSymbol because we
# know whether or not the symbol exists, and don't want
# to the overhead of error/duplicate checking.
# cache frequently called functions
create_symbol_func = SymbolMap.createSymbol
create_symbols_func = SymbolMap.createSymbols
alias_symbol_func = SymbolMap.alias
variable_label_pairs = []
# populate the symbol map in a single pass.
#objective_list, constraint_list, sosconstraint_list, variable_list \
# = self._populate_symbol_map(model,
# symbol_map,
# labeler,
# variable_symbol_map,
# file_determinism=file_determinism)
sortOrder = SortComponents.unsorted
if file_determinism >= 1:
sortOrder = sortOrder | SortComponents.indices
if file_determinism >= 2:
sortOrder = sortOrder | SortComponents.alphabetical
#
# Create variable symbols (and cache the block list)
#
all_blocks = []
variable_list = []
for block in model.block_data_objects(active=True, sort=sortOrder):
all_blocks.append(block)
for vardata in block.component_data_objects(Var,
active=True,
sort=sortOrder,
descend_into=False):
variable_list.append(vardata)
variable_label_pairs.append(
(vardata, create_symbol_func(symbol_map, vardata,
labeler)))
variable_symbol_map.addSymbols(variable_label_pairs)
# and extract the information we'll need for rapid labeling.
object_symbol_dictionary = symbol_map.byObject
variable_symbol_dictionary = variable_symbol_map.byObject
# cache - these are called all the time.
print_expr_canonical = self._print_expr_canonical
# print the model name and the source, so we know roughly where
# it came from.
#
# NOTE: this *must* use the "\* ... *\" comment format: the GLPK
# LP parser does not correctly handle other formats (notably, "%").
output_file.write("\\* Source Pyomo model name=%s *\\\n\n" %
(model.name, ))
#
# Objective
#
supports_quadratic_objective = \
solver_capability('quadratic_objective')
numObj = 0
onames = []
for block in all_blocks:
gen_obj_canonical_repn = \
getattr(block, "_gen_obj_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block, '_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for objective_data in block.component_data_objects(
Objective, active=True, sort=sortOrder,
descend_into=False):
numObj += 1
onames.append(objective_data.name)
if numObj > 1:
raise ValueError(
"More than one active objective defined for input "
"model '%s'; Cannot write legal LP file\n"
"Objectives: %s" % (model.name, ' '.join(onames)))
create_symbol_func(symbol_map, objective_data, labeler)
symbol_map.alias(objective_data, '__default_objective__')
if objective_data.is_minimizing():
output_file.write("min \n")
else:
output_file.write("max \n")
if gen_obj_canonical_repn:
canonical_repn = \
generate_canonical_repn(objective_data.expr)
block_canonical_repn[objective_data] = canonical_repn
else:
canonical_repn = block_canonical_repn[objective_data]
degree = canonical_degree(canonical_repn)
if degree == 0:
logger.warning(
"Constant objective detected, replacing "
"with a placeholder to prevent solver failure.")
force_objective_constant = True
elif degree == 2:
if not supports_quadratic_objective:
raise RuntimeError(
"Selected solver is unable to handle "
"objective functions with quadratic terms. "
"Objective at issue: %s." % objective_data.name)
elif degree != 1:
raise RuntimeError(
"Cannot write legal LP file. Objective '%s' "
"has nonlinear terms that are not quadratic." %
objective_data.name)
output_file.write(
object_symbol_dictionary[id(objective_data)] + ':\n')
offset = print_expr_canonical(
canonical_repn,
output_file,
object_symbol_dictionary,
variable_symbol_dictionary,
True,
column_order,
force_objective_constant=force_objective_constant)
if numObj == 0:
raise ValueError(
"ERROR: No objectives defined for input model '%s'; "
" cannot write legal LP file" % str(model.name))
# Constraints
#
# If there are no non-trivial constraints, you'll end up with an empty
# constraint block. CPLEX is OK with this, but GLPK isn't. And
# eliminating the constraint block (i.e., the "s.t." line) causes GLPK
# to whine elsewhere. Output a warning if the constraint block is empty,
# so users can quickly determine the cause of the solve failure.
output_file.write("\n")
output_file.write("s.t.\n")
output_file.write("\n")
have_nontrivial = False
supports_quadratic_constraint = solver_capability(
'quadratic_constraint')
def constraint_generator():
for block in all_blocks:
gen_con_canonical_repn = \
getattr(block, "_gen_con_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block, '_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for constraint_data in block.component_data_objects(
Constraint,
active=True,
sort=sortOrder,
descend_into=False):
if isinstance(constraint_data, LinearCanonicalRepn):
canonical_repn = constraint_data
else:
if gen_con_canonical_repn:
canonical_repn = generate_canonical_repn(
constraint_data.body)
block_canonical_repn[
constraint_data] = canonical_repn
else:
canonical_repn = block_canonical_repn[
constraint_data]
yield constraint_data, canonical_repn
if row_order is not None:
sorted_constraint_list = list(constraint_generator())
sorted_constraint_list.sort(key=lambda x: row_order[x[0]])
def yield_all_constraints():
for constraint_data, canonical_repn in sorted_constraint_list:
yield constraint_data, canonical_repn
else:
yield_all_constraints = constraint_generator
# FIXME: This is a hack to get nested blocks working...
eq_string_template = "= %" + self._precision_string + '\n'
geq_string_template = ">= %" + self._precision_string + '\n\n'
leq_string_template = "<= %" + self._precision_string + '\n\n'
for constraint_data, canonical_repn in yield_all_constraints():
have_nontrivial = True
degree = canonical_degree(canonical_repn)
#
# Write constraint
#
# There are conditions, e.g., when fixing variables, under which
# a constraint block might be empty. Ignore these, for both
# practical reasons and the fact that the CPLEX LP format
# requires a variable in the constraint body. It is also
# possible that the body of the constraint consists of only a
# constant, in which case the "variable" of
if degree == 0:
if skip_trivial_constraints:
continue
elif degree == 2:
if not supports_quadratic_constraint:
raise ValueError(
"Solver unable to handle quadratic expressions. Constraint"
" at issue: '%s'" % (constraint_data.name))
elif degree != 1:
raise ValueError(
"Cannot write legal LP file. Constraint '%s' has a body "
"with nonlinear terms." % (constraint_data.name))
# Create symbol
con_symbol = create_symbol_func(symbol_map, constraint_data,
labeler)
if constraint_data.equality:
label = 'c_e_' + con_symbol + '_'
alias_symbol_func(symbol_map, constraint_data, label)
output_file.write(label + ':\n')
offset = print_expr_canonical(canonical_repn, output_file,
object_symbol_dictionary,
variable_symbol_dictionary,
False, column_order)
bound = constraint_data.lower
bound = self._get_bound(bound) - offset
output_file.write(eq_string_template %
(_no_negative_zero(bound)))
output_file.write("\n")
else:
if constraint_data.lower is not None:
if constraint_data.upper is not None:
label = 'r_l_' + con_symbol + '_'
else:
label = 'c_l_' + con_symbol + '_'
alias_symbol_func(symbol_map, constraint_data, label)
output_file.write(label + ':\n')
offset = print_expr_canonical(canonical_repn, output_file,
object_symbol_dictionary,
variable_symbol_dictionary,
False, column_order)
bound = constraint_data.lower
bound = self._get_bound(bound) - offset
output_file.write(geq_string_template %
(_no_negative_zero(bound)))
if constraint_data.upper is not None:
if constraint_data.lower is not None:
label = 'r_u_' + con_symbol + '_'
else:
label = 'c_u_' + con_symbol + '_'
alias_symbol_func(symbol_map, constraint_data, label)
output_file.write(label + ':\n')
offset = print_expr_canonical(canonical_repn, output_file,
object_symbol_dictionary,
variable_symbol_dictionary,
False, column_order)
bound = constraint_data.upper
bound = self._get_bound(bound) - offset
output_file.write(leq_string_template %
(_no_negative_zero(bound)))
if not have_nontrivial:
logger.warning('Empty constraint block written in LP format ' \
'- solver may error')
# the CPLEX LP format doesn't allow constants in the objective (or
# constraint body), which is a bit silly. To avoid painful
# book-keeping, we introduce the following "variable", constrained
# to the value 1. This is used when quadratic terms are present.
# worst-case, if not used, is that CPLEX easily pre-processes it out.
prefix = ""
output_file.write('%sc_e_ONE_VAR_CONSTANT: \n' % prefix)
output_file.write('%sONE_VAR_CONSTANT = 1.0\n' % prefix)
output_file.write("\n")
# SOS constraints
#
# For now, we write out SOS1 and SOS2 constraints in the cplex format
#
# All Component objects are stored in model._component, which is a
# dictionary of {class: {objName: object}}.
#
# Consider the variable X,
#
# model.X = Var(...)
#
# We print X to CPLEX format as X(i,j,k,...) where i, j, k, ... are the
# indices of X.
#
SOSlines = StringIO()
sos1 = solver_capability("sos1")
sos2 = solver_capability("sos2")
writtenSOS = False
for block in all_blocks:
for soscondata in block.component_data_objects(SOSConstraint,
active=True,
sort=sortOrder,
descend_into=False):
create_symbol_func(symbol_map, soscondata, labeler)
level = soscondata.level
if (level == 1 and not sos1) or \
(level == 2 and not sos2) or \
(level > 2):
raise ValueError(
"Solver does not support SOS level %s constraints" %
(level))
if writtenSOS == False:
SOSlines.write("SOS\n")
writtenSOS = True
# This updates the referenced_variable_ids, just in case
# there is a variable that only appears in an
# SOSConstraint, in which case this needs to be known
# before we write the "bounds" section (Cplex does not
# handle this correctly, Gurobi does)
self.printSOS(symbol_map, labeler, variable_symbol_map,
soscondata, SOSlines)
#
# Bounds
#
output_file.write("bounds\n")
# Scan all variables even if we're only writing a subset of them.
# required because we don't store maps by variable type currently.
# FIXME: This is a hack to get nested blocks working...
lb_string_template = "%" + self._precision_string + " <= "
ub_string_template = " <= %" + self._precision_string + "\n"
# Track the number of integer and binary variables, so you can
# output their status later.
integer_vars = []
binary_vars = []
for vardata in variable_list:
# TODO: We could just loop over the set of items in
# self._referenced_variable_ids, except this is
# a dictionary that is hashed by id(vardata)
# which would make the bounds section
# nondeterministic (bad for unit testing)
if (not include_all_variable_bounds) and \
(id(vardata) not in self._referenced_variable_ids):
continue
if vardata.fixed:
if not output_fixed_variable_bounds:
raise ValueError(
"Encountered a fixed variable (%s) inside an active "
"objective or constraint expression on model %s, which is "
"usually indicative of a preprocessing error. Use the "
"IO-option 'output_fixed_variable_bounds=True' to suppress "
"this error and fix the variable by overwriting its bounds "
"in the LP file." % (vardata.name, model.name))
if vardata.value is None:
raise ValueError(
"Variable cannot be fixed to a value of None.")
vardata_lb = value(vardata.value)
vardata_ub = value(vardata.value)
else:
vardata_lb = self._get_bound(vardata.lb)
vardata_ub = self._get_bound(vardata.ub)
name_to_output = variable_symbol_dictionary[id(vardata)]
# track the number of integer and binary variables, so we know whether
# to output the general / binary sections below.
if vardata.is_binary():
binary_vars.append(name_to_output)
elif vardata.is_integer():
integer_vars.append(name_to_output)
elif not vardata.is_continuous():
raise TypeError(
"Invalid domain type for variable with name '%s'. "
"Variable is not continuous, integer, or binary." %
(vardata.name))
# in the CPLEX LP file format, the default variable
# bounds are 0 and +inf. These bounds are in
# conflict with Pyomo, which assumes -inf and +inf
# (which we would argue is more rational).
output_file.write(" ")
if (vardata_lb is not None) and (vardata_lb != -infinity):
output_file.write(lb_string_template %
(_no_negative_zero(vardata_lb)))
else:
output_file.write(" -inf <= ")
if name_to_output == "e":
raise ValueError(
"Attempting to write variable with name 'e' in a CPLEX LP "
"formatted file will cause a parse failure due to confusion with "
"numeric values expressed in scientific notation")
output_file.write(name_to_output)
if (vardata_ub is not None) and (vardata_ub != infinity):
output_file.write(ub_string_template %
(_no_negative_zero(vardata_ub)))
else:
output_file.write(" <= +inf\n")
if len(integer_vars) > 0:
output_file.write("general\n")
for var_name in integer_vars:
output_file.write(' %s\n' % var_name)
if len(binary_vars) > 0:
output_file.write("binary\n")
for var_name in binary_vars:
output_file.write(' %s\n' % var_name)
# Write the SOS section
output_file.write(SOSlines.getvalue())
#
# wrap-up
#
output_file.write("end\n")
# Clean up the symbol map to only contain variables referenced
# in the active constraints **Note**: warm start method may
# rely on this for choosing the set of potential warm start
# variables
vars_to_delete = set(variable_symbol_map.byObject.keys()) - \
set(self._referenced_variable_ids.keys())
sm_byObject = symbol_map.byObject
sm_bySymbol = symbol_map.bySymbol
var_sm_byObject = variable_symbol_map.byObject
for varid in vars_to_delete:
symbol = var_sm_byObject[varid]
del sm_byObject[varid]
del sm_bySymbol[symbol]
del variable_symbol_map
return symbol_map
def to_standard_form(self):
"""
Produces a standard-form representation of the model. Returns
the coefficient matrix (A), the cost vector (c), and the
constraint vector (b), where the 'standard form' problem is
min/max c'x
s.t. Ax = b
x >= 0
All three returned values are instances of the array.array
class, and store Python floats (C doubles).
"""
from pyomo.repn import generate_canonical_repn
# We first need to create an map of all variables to their column
# number
colID = {}
ID2name = {}
id = 0
tmp = self.variables().keys()
tmp.sort()
for v in tmp:
colID[v] = id
ID2name[id] = v
id += 1
# First we go through the constraints and introduce slack and excess
# variables to eliminate inequality constraints
#
# N.B. Structure heirarchy:
#
# active_components: {class: {attr_name: object}}
# object -> Constraint: ._data: {ndx: _ConstraintData}
# _ConstraintData: .lower, .body, .upper
#
# So, altogether, we access a lower bound via
#
# model.component_map(active=True)[Constraint]['con_name']['index'].lower
#
# {le,ge,eq}Constraints are
# {constraint_name: {index: {variable_or_none: coefficient}} objects
# that represent each constraint. None in the innermost dictionary
# represents the constant term.
#
# i.e.
#
# min x1 + 2*x2 + x4
# s.t. x1 = 1
# x2 + 3*x3 <= -1
# x1 + x4 >= 3
# x1 + 2*x2 + + 3*x4 >= 0
#
#
# would be represented as (modulo the names of the variables,
# constraints, and indices)
#
# eqConstraints = {'c1': {None: {'x1':1, None:-1}}}
# leConstraints = {'c2': {None: {'x2':1, 'x3':3, None:1}}}
# geConstraints = {'c3': {None: {'x1':1, 'x4':1, None:-3}},
# 'c4': {None: {'x1':1, 'x2':2, 'x4':1, None:0}}}
#
# Note the we have the luxury of dealing only with linear terms.
var_id_map = {}
leConstraints = {}
geConstraints = {}
eqConstraints = {}
objectives = {}
# For each registered component
for c in self.component_map(active=True):
# Get all subclasses of Constraint
if issubclass(c, Constraint):
cons = self.component_map(c, active=True)
# Get the name of the constraint, and the constraint set itself
for con_set_name in cons:
con_set = cons[con_set_name]
# For each indexed constraint in the constraint set
for ndx in con_set._data:
con = con_set._data[ndx]
# Process the body
terms = self._process_canonical_repn(
generate_canonical_repn(con.body, var_id_map))
# Process the bounds of the constraint
if con.equality:
# Equality constraint, only check lower bound
lb = self._process_canonical_repn(
generate_canonical_repn(con.lower, var_id_map))
# Update terms
for k in lb:
v = lb[k]
if k in terms:
terms[k] -= v
else:
terms[k] = -v
# Add constraint to equality constraints
eqConstraints[(con_set_name, ndx)] = terms
else:
# Process upper bounds (<= constraints)
if con.upper is not None:
# Less than or equal to constraint
tmp = dict(terms)
ub = self._process_canonical_repn(
generate_canonical_repn(con.upper, var_id_map))
# Update terms
for k in ub:
if k in terms:
tmp[k] -= ub[k]
else:
tmp[k] = -ub[k]
# Add constraint to less than or equal to
# constraints
leConstraints[(con_set_name, ndx)] = tmp
# Process lower bounds (>= constraints)
if con.lower is not None:
# Less than or equal to constraint
tmp = dict(terms)
lb = self._process_canonical_repn(
generate_canonical_repn(con.lower, var_id_map))
# Update terms
for k in lb:
if k in terms:
tmp[k] -= lb[k]
else:
tmp[k] = -lb[k]
# Add constraint to less than or equal to
# constraints
geConstraints[(con_set_name, ndx)] = tmp
elif issubclass(c, Objective):
# Process objectives
objs = self.component_map(c, active=True)
# Get the name of the objective, and the objective set itself
for obj_set_name in objs:
obj_set = objs[obj_set_name]
# For each indexed objective in the objective set
for ndx in obj_set._data:
obj = obj_set._data[ndx]
# Process the objective
terms = self._process_canonical_repn(
generate_canonical_repn(obj.expr, var_id_map))
objectives[(obj_set_name, ndx)] = terms
# We now have all the constraints. Add a slack variable for every
# <= constraint and an excess variable for every >= constraint.
nSlack = len(leConstraints)
nExcess = len(geConstraints)
nConstraints = len(leConstraints) + len(geConstraints) + \
len(eqConstraints)
nVariables = len(colID) + nSlack + nExcess
nRegVariables = len(colID)
# Make the arrays
coefficients = array.array("d", [0] * nConstraints * nVariables)
constraints = array.array("d", [0] * nConstraints)
costs = array.array("d", [0] * nVariables)
# Populate the coefficient matrix
constraintID = 0
# Add less than or equal to constraints
for ndx in leConstraints:
con = leConstraints[ndx]
for termKey in con:
coef = con[termKey]
if termKey is None:
# Constraint coefficient
constraints[constraintID] = -coef
else:
# Variable coefficient
col = colID[termKey]
coefficients[constraintID * nVariables + col] = coef
# Add the slack
coefficients[constraintID*nVariables + nRegVariables + \
constraintID] = 1
constraintID += 1
# Add greater than or equal to constraints
for ndx in geConstraints:
con = geConstraints[ndx]
for termKey in con:
coef = con[termKey]
if termKey is None:
# Constraint coefficient
constraints[constraintID] = -coef
else:
# Variable coefficient
col = colID[termKey]
coefficients[constraintID * nVariables + col] = coef
# Add the slack
coefficients[constraintID*nVariables + nRegVariables + \
constraintID] = -1
constraintID += 1
# Add equality constraints
for ndx in eqConstraints:
con = eqConstraints[ndx]
for termKey in con:
coef = con[termKey]
if termKey is None:
# Constraint coefficient
constraints[constraintID] = -coef
else:
# Variable coefficient
col = colID[termKey]
coefficients[constraintID * nVariables + col] = coef
constraintID += 1
# Determine cost coefficients
for obj_name in objectives:
obj = objectives[obj_name]()
for var in obj:
costs[colID[var]] = obj[var]
# Print the model
#
# The goal is to print
#
# var1 var2 var3 ...
# +-- --+
# | cost1 cost2 cost3 ...|
# +-- --+
# +-- --+ +-- --+
# con1 | coef11 coef12 coef13 ...| | eq1 |
# con2 | coef21 coef22 coef23 ...| | eq2 |
# con2 | coef31 coef32 coef33 ...| | eq3 |
# . | . . . . | | . |
# . | . . . . | | . |
# . | . . . . | | . |
constraintPadding = 2
numFmt = "% 1.4f"
altFmt = "% 1.1g"
maxColWidth = max(len(numFmt % 0.0), len(altFmt % 0.0))
maxConstraintColWidth = max(len(numFmt % 0.0), len(altFmt % 0.0))
# Generate constraint names
maxConNameLen = 0
conNames = []
for name in leConstraints:
strName = str(name)
if len(strName) > maxConNameLen:
maxConNameLen = len(strName)
conNames.append(strName)
for name in geConstraints:
strName = str(name)
if len(strName) > maxConNameLen:
maxConNameLen = len(strName)
conNames.append(strName)
for name in eqConstraints:
strName = str(name)
if len(strName) > maxConNameLen:
maxConNameLen = len(strName)
conNames.append(strName)
# Generate the variable names
varNames = [None] * len(colID)
for name in colID:
tmp_name = " " + name
if len(tmp_name) > maxColWidth:
maxColWidth = len(tmp_name)
varNames[colID[name]] = tmp_name
for i in xrange(0, nSlack):
tmp_name = " _slack_%i" % i
if len(tmp_name) > maxColWidth:
maxColWidth = len(tmp_name)
varNames.append(tmp_name)
for i in xrange(0, nExcess):
tmp_name = " _excess_%i" % i
if len(tmp_name) > maxColWidth:
maxColWidth = len(tmp_name)
varNames.append(tmp_name)
# Variable names
line = " " * maxConNameLen + (" " * constraintPadding) + " "
for col in xrange(0, nVariables):
# Format entry
token = varNames[col]
# Pad with trailing whitespace
token += " " * (maxColWidth - len(token))
# Add to line
line += " " + token + " "
print(line + '\n')
# Cost vector
print(" "*maxConNameLen + (" "*constraintPadding) + "+--" + \
" "*((maxColWidth+2)*nVariables - 4) + "--+" + '\n')
line = " " * maxConNameLen + (" " * constraintPadding) + "|"
for col in xrange(0, nVariables):
# Format entry
token = numFmt % costs[col]
if len(token) > maxColWidth:
token = altFmt % costs[col]
# Pad with trailing whitespace
token += " " * (maxColWidth - len(token))
# Add to line
line += " " + token + " "
line += "|"
print(line + '\n')
print(" "*maxConNameLen + (" "*constraintPadding) + "+--" + \
" "*((maxColWidth+2)*nVariables - 4) + "--+"+'\n')
# Constraints
print(" "*maxConNameLen + (" "*constraintPadding) + "+--" + \
" "*((maxColWidth+2)*nVariables - 4) + "--+" + \
(" "*constraintPadding) + "+--" + \
(" "*(maxConstraintColWidth-1)) + "--+"+'\n')
for row in xrange(0, nConstraints):
# Print constraint name
line = conNames[row] + (" " * constraintPadding) + (
" " * (maxConNameLen - len(conNames[row]))) + "|"
# Print each coefficient
for col in xrange(0, nVariables):
# Format entry
token = numFmt % coefficients[nVariables * row + col]
if len(token) > maxColWidth:
token = altFmt % coefficients[nVariables * row + col]
# Pad with trailing whitespace
token += " " * (maxColWidth - len(token))
# Add to line
line += " " + token + " "
line += "|" + (" " * constraintPadding) + "|"
# Add constraint vector
token = numFmt % constraints[row]
if len(token) > maxConstraintColWidth:
token = altFmt % constraints[row]
# Pad with trailing whitespace
token += " " * (maxConstraintColWidth - len(token))
line += " " + token + " |"
print(line + '\n')
print(" "*maxConNameLen + (" "*constraintPadding) + "+--" + \
" "*((maxColWidth+2)*nVariables - 4) + "--+" + \
(" "*constraintPadding) + "+--" + (" "*(maxConstraintColWidth-1))\
+ "--+"+'\n')
return (coefficients, costs, constraints)
def compile_objective(self, pyomo_instance):
from pyomo.core.base import Objective
from pyomo.repn import canonical_is_constant, LinearCanonicalRepn, canonical_degree
if self._active_cplex_instance is None:
raise RuntimeError("***The CPLEXPersistent solver plugin "
"cannot compile objective - no "
"instance is presently compiled")
cplex_instance = self._active_cplex_instance
self._has_quadratic_objective = False
cntr = 0
for block in pyomo_instance.block_data_objects(active=True):
gen_obj_canonical_repn = \
getattr(block, "_gen_obj_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for obj_data in block.component_data_objects(Objective,
active=True,
descend_into=False):
cntr += 1
if cntr > 1:
raise ValueError(
"Multiple active objectives found on Pyomo instance '%s'. "
"Solver '%s' will only handle a single active objective" \
% (pyomo_instance.name, self.type))
if obj_data.is_minimizing():
cplex_instance.objective.set_sense(
cplex_instance.objective.sense.minimize)
else:
cplex_instance.objective.set_sense(
cplex_instance.objective.sense.maximize)
cplex_instance.objective.set_name(
self._symbol_map.getSymbol(obj_data,
self._labeler))
if gen_obj_canonical_repn:
obj_repn = generate_canonical_repn(obj_data.expr)
block_canonical_repn[obj_data] = obj_repn
else:
obj_repn = block_canonical_repn[obj_data]
if (isinstance(obj_repn, LinearCanonicalRepn) and \
((obj_repn.linear == None) or \
(len(obj_repn.linear) == 0))) or \
canonical_is_constant(obj_repn):
print("Warning: Constant objective detected, replacing "
"with a placeholder to prevent solver failure.")
offset = obj_repn.constant
if offset is None:
offset = 0.0
objective_expression = [("ONE_VAR_CONSTANT",offset)]
cplex_instance.objective.set_linear(objective_expression)
else:
if isinstance(obj_repn, LinearCanonicalRepn):
objective_expression, offset = \
self._encode_constraint_body_linear_specialized(
obj_repn,
self._labeler,
use_variable_names=False,
cplex_variable_name_index_map=self._cplex_variable_ids,
as_pairs=True)
if offset != 0.0:
objective_expression.append((self._cplex_variable_ids["ONE_VAR_CONSTANT"],offset))
cplex_instance.objective.set_linear(objective_expression)
else:
#Linear terms
if 1 in obj_repn:
objective_expression, offset = \
self._encode_constraint_body_linear(
obj_repn,
self._labeler,
as_pairs=True)
if offset != 0.0:
objective_expression.append(("ONE_VAR_CONSTANT",offset))
cplex_instance.objective.set_linear(objective_expression)
#Quadratic terms
if 2 in obj_repn:
self._has_quadratic_objective = True
objective_expression = \
self._encode_constraint_body_quadratic(obj_repn,
self._labeler,
as_triples=True,
is_obj=2.0)
cplex_instance.objective.\
set_quadratic_coefficients(objective_expression)
degree = canonical_degree(obj_repn)
if (degree is None) or (degree > 2):
raise ValueError(
"CPLEXPersistent plugin does not support general nonlinear "
"objective expressions (only linear or quadratic).\n"
"Objective: %s" % (obj_data.name))
def _add_optimality_conditions(self, instance, submodel):
"""
Add optimality conditions for the submodel
This assumes that the original model has the form:
min c1*x + d1*y
A3*x <= b3
A1*x + B1*y <= b1
min c2*x + d2*y
y >= 0
A2*x + B2*y <= b2
NOTE THE VARIABLE BOUNDS!
"""
#
# Populate the block with the linear constraints.
# Note that we don't simply clone the current block.
# We need to collect a single set of equations that
# can be easily expressed.
#
d2 = {}
B2 = {}
vtmp = {}
utmp = {}
sids_set = set()
sids_list = []
#
block = Block(concrete=True)
block.u = VarList()
block.v = VarList()
block.c1 = ConstraintList()
block.c2 = ComplementarityList()
block.c3 = ComplementarityList()
#
# Collect submodel objective terms
#
for odata in submodel.component_data_objects(Objective, active=True):
if odata.sense == maximize:
d_sense = -1
else:
d_sense = 1
#
# Iterate through the variables in the canonical representation
#
o_terms = generate_canonical_repn(odata.expr, compute_values=False)
for i in range(len(o_terms.variables)):
var = o_terms.variables[i]
if var.parent_component().local_name in self._fixed_upper_vars:
#
# Skip fixed upper variables
#
continue
#
# Store the coefficient for the variable. The coefficient is
# negated if the objective is maximized.
#
id_ = id(var)
d2[id_] = d_sense * o_terms.linear[i]
if not id_ in sids_set:
sids_set.add(id_)
sids_list.append(id_)
# Stop after the first objective
break
#
# Iterate through all lower level variables, adding dual variables
# and complementarity slackness conditions for y bound constraints
#
for vcomponent in instance.component_objects(Var, active=True):
if vcomponent.local_name in self._fixed_upper_vars:
#
# Skip fixed upper variables
#
continue
for ndx in vcomponent:
#
# For each index, get the bounds for the variable
#
lb, ub = vcomponent[ndx].bounds
if not lb is None:
#
# Add the complementarity slackness condition for a lower bound
#
v = block.v.add()
block.c3.add( complements(vcomponent[ndx] >= lb, v >= 0) )
else:
v = None
if not ub is None:
#
# Add the complementarity slackness condition for an upper bound
#
w = block.v.add()
vtmp[id(vcomponent[ndx])] = w
block.c3.add( complements(vcomponent[ndx] <= ub, w >= 0) )
else:
w = None
if not (v is None and w is None):
#
# Record the variables for which complementarity slackness conditions
# were created.
#
id_ = id(vcomponent[ndx])
vtmp[id_] = (v,w)
if not id_ in sids_set:
sids_set.add(id_)
sids_list.append(id_)
#
# Iterate through all constraints, adding dual variables and
# complementary slackness conditions (for inequality constraints)
#
for cdata in submodel.component_data_objects(Constraint, active=True):
if cdata.equality:
# Don't add a complementary slackness condition for an equality constraint
u = block.u.add()
utmp[id(cdata)] = (None,u)
else:
if not cdata.lower is None:
#
# Add the complementarity slackness condition for a greater-than inequality
#
u = block.u.add()
block.c2.add( complements(- cdata.body <= - cdata.lower, u >= 0) )
else:
u = None
if not cdata.upper is None:
#
# Add the complementarity slackness condition for a less-than inequality
#
w = block.u.add()
block.c2.add( complements(cdata.body <= cdata.upper, w >= 0) )
else:
w = None
if not (u is None and w is None):
utmp[id(cdata)] = (u,w)
#
# Store the coefficients for the contraint variables that are not fixed
#
c_terms = generate_canonical_repn(cdata.body, compute_values=False)
for i in range(len(c_terms.variables)):
var = c_terms.variables[i]
if var.parent_component().local_name in self._fixed_upper_vars:
continue
id_ = id(var)
B2.setdefault(id_,{}).setdefault(id(cdata),c_terms.linear[i])
if not id_ in sids_set:
sids_set.add(id_)
sids_list.append(id_)
#
# Generate stationarity equations
#
tmp__ = (None, None)
for vid in sids_list:
exp = d2.get(vid,0)
#
lb_dual, ub_dual = vtmp.get(vid, tmp__)
if vid in vtmp:
if not lb_dual is None:
exp -= lb_dual # dual for variable lower bound
if not ub_dual is None:
exp += ub_dual # dual for variable upper bound
#
B2_ = B2.get(vid,{})
utmp_keys = list(utmp.keys())
if self._deterministic:
utmp_keys.sort(key=lambda x:utmp[x][0].local_name if utmp[x][1] is None else utmp[x][1].local_name)
for uid in utmp_keys:
if uid in B2_:
lb_dual, ub_dual = utmp[uid]
if not lb_dual is None:
exp -= B2_[uid] * lb_dual
if not ub_dual is None:
exp += B2_[uid] * ub_dual
if type(exp) in six.integer_types or type(exp) is float:
# TODO: Annotate the model as unbounded
raise IOError("Unbounded variable without side constraints")
else:
block.c1.add( exp == 0 )
#
# Return block
#
return block
def _replace_bilinear(self, expr, instance):
idMap = {}
terms = generate_canonical_repn(expr, idMap=idMap)
# Constant
if 0 in terms:
e = terms[0][None]
else:
e = 0
# Linear terms
if 1 in terms:
for key in terms[1]:
e += terms[1][key] * idMap[key]
# Quadratic terms
if 2 in terms:
for key in terms[2]:
vars = []
for v in key:
vars.append(idMap[v])
coef = terms[2][key]
#
if isinstance(vars[0].domain, BooleanSet):
instance.bilinear_data_.vlist_boolean.append(vars[0])
v = instance.bilinear_data_.vlist.add()
bounds = vars[1].bounds
v.setlb(bounds[0])
v.setub(bounds[1])
id = len(instance.bilinear_data_.vlist)
instance.bilinear_data_.index.add(id)
# First disjunct
d0 = instance.bilinear_data_.disjuncts_[id,0]
d0.c1 = Constraint(expr=vars[0] == 1)
d0.c2 = Constraint(expr=v == coef*vars[1])
# Second disjunct
d1 = instance.bilinear_data_.disjuncts_[id,1]
d1.c1 = Constraint(expr=vars[0] == 0)
d1.c2 = Constraint(expr=v == 0)
# Disjunction
instance.bilinear_data_.disjunction_data[id] = [instance.bilinear_data_.disjuncts_[id,0], instance.bilinear_data_.disjuncts_[id,1]]
instance.bilinear_data_.disjunction_data[id] = [instance.bilinear_data_.disjuncts_[id,0], instance.bilinear_data_.disjuncts_[id,1]]
# The disjunctive variable is the expression
e += v
#
elif isinstance(vars[1].domain, BooleanSet):
instance.bilinear_data_.vlist_boolean.append(vars[1])
v = instance.bilinear_data_.vlist.add()
bounds = vars[0].bounds
v.setlb(bounds[0])
v.setub(bounds[1])
id = len(instance.bilinear_data_.vlist)
instance.bilinear_data_.index.add(id)
# First disjunct
d0 = instance.bilinear_data_.disjuncts_[id,0]
d0.c1 = Constraint(expr=vars[1] == 1)
d0.c2 = Constraint(expr=v == coef*vars[0])
# Second disjunct
d1 = instance.bilinear_data_.disjuncts_[id,1]
d1.c1 = Constraint(expr=vars[1] == 0)
d1.c2 = Constraint(expr=v == 0)
# Disjunction
instance.bilinear_data_.disjunction_data[id] = [instance.bilinear_data_.disjuncts_[id,0], instance.bilinear_data_.disjuncts_[id,1]]
# The disjunctive variable is the expression
e += v
else:
# If neither variable is boolean, just reinsert the original bilinear term
e += coef*vars[0]*vars[1]
#
return e
def _add_optimality_conditions(self, instance, submodel):
"""
Add optimality conditions for the submodel
This assumes that the original model has the form:
min c1*x + d1*y
A3*x <= b3
A1*x + B1*y <= b1
min c2*x + d2*y
y >= 0
A2*x + B2*y <= b2
NOTE THE VARIABLE BOUNDS!
"""
#
# Populate the block with the linear constraints.
# Note that we don't simply clone the current block.
# We need to collect a single set of equations that
# can be easily expressed.
#
d2 = {}
B2 = {}
vtmp = {}
utmp = {}
sids_set = set()
sids_list = []
#
block = Block(concrete=True)
block.u = VarList()
block.v = VarList()
block.c1 = ConstraintList()
block.c2 = ComplementarityList()
block.c3 = ComplementarityList()
#
# Collect submodel objective terms
#
for odata in submodel.component_data_objects(Objective, active=True):
if odata.sense == maximize:
d_sense = -1
else:
d_sense = 1
#
# Iterate through the variables in the canonical representation
#
o_terms = generate_canonical_repn(odata.expr, compute_values=False)
for i in range(len(o_terms.variables)):
var = o_terms.variables[i]
if var.parent_component().local_name in self._fixed_upper_vars:
#
# Skip fixed upper variables
#
continue
#
# Store the coefficient for the variable. The coefficient is
# negated if the objective is maximized.
#
id_ = id(var)
d2[id_] = d_sense * o_terms.linear[i]
if not id_ in sids_set:
sids_set.add(id_)
sids_list.append(id_)
# Stop after the first objective
break
#
# Iterate through all lower level variables, adding dual variables
# and complementarity slackness conditions for y bound constraints
#
for vcomponent in instance.component_objects(Var, active=True):
if vcomponent.local_name in self._fixed_upper_vars:
#
# Skip fixed upper variables
#
continue
for ndx in vcomponent:
#
# For each index, get the bounds for the variable
#
lb, ub = vcomponent[ndx].bounds
if not lb is None:
#
# Add the complementarity slackness condition for a lower bound
#
v = block.v.add()
block.c3.add(complements(vcomponent[ndx] >= lb, v >= 0))
else:
v = None
if not ub is None:
#
# Add the complementarity slackness condition for an upper bound
#
w = block.v.add()
vtmp[id(vcomponent[ndx])] = w
block.c3.add(complements(vcomponent[ndx] <= ub, w >= 0))
else:
w = None
if not (v is None and w is None):
#
# Record the variables for which complementarity slackness conditions
# were created.
#
id_ = id(vcomponent[ndx])
vtmp[id_] = (v, w)
if not id_ in sids_set:
sids_set.add(id_)
sids_list.append(id_)
#
# Iterate through all constraints, adding dual variables and
# complementary slackness conditions (for inequality constraints)
#
for cdata in submodel.component_data_objects(Constraint, active=True):
if cdata.equality:
# Don't add a complementary slackness condition for an equality constraint
u = block.u.add()
utmp[id(cdata)] = (None, u)
else:
if not cdata.lower is None:
#
# Add the complementarity slackness condition for a greater-than inequality
#
u = block.u.add()
block.c2.add(
complements(-cdata.body <= -cdata.lower, u >= 0))
else:
u = None
if not cdata.upper is None:
#
# Add the complementarity slackness condition for a less-than inequality
#
w = block.u.add()
block.c2.add(complements(cdata.body <= cdata.upper,
w >= 0))
else:
w = None
if not (u is None and w is None):
utmp[id(cdata)] = (u, w)
#
# Store the coefficients for the contraint variables that are not fixed
#
c_terms = generate_canonical_repn(cdata.body, compute_values=False)
for i in range(len(c_terms.variables)):
var = c_terms.variables[i]
if var.parent_component().local_name in self._fixed_upper_vars:
continue
id_ = id(var)
B2.setdefault(id_, {}).setdefault(id(cdata), c_terms.linear[i])
if not id_ in sids_set:
sids_set.add(id_)
sids_list.append(id_)
#
# Generate stationarity equations
#
tmp__ = (None, None)
for vid in sids_list:
exp = d2.get(vid, 0)
#
lb_dual, ub_dual = vtmp.get(vid, tmp__)
if vid in vtmp:
if not lb_dual is None:
exp -= lb_dual # dual for variable lower bound
if not ub_dual is None:
exp += ub_dual # dual for variable upper bound
#
B2_ = B2.get(vid, {})
utmp_keys = list(utmp.keys())
if self._deterministic:
utmp_keys.sort(key=lambda x: utmp[x][0].local_name if utmp[x][
1] is None else utmp[x][1].local_name)
for uid in utmp_keys:
if uid in B2_:
lb_dual, ub_dual = utmp[uid]
if not lb_dual is None:
exp -= B2_[uid] * lb_dual
if not ub_dual is None:
exp += B2_[uid] * ub_dual
if type(exp) in six.integer_types or type(exp) is float:
# TODO: Annotate the model as unbounded
raise IOError("Unbounded variable without side constraints")
else:
block.c1.add(exp == 0)
#
# Return block
#
return block
def _print_model_LP(self,
model,
output_file,
solver_capability,
labeler,
output_fixed_variable_bounds=False,
file_determinism=1,
row_order=None,
column_order=None,
skip_trivial_constraints=False,
force_objective_constant=False,
include_all_variable_bounds=False):
symbol_map = SymbolMap()
variable_symbol_map = SymbolMap()
# NOTE: we use createSymbol instead of getSymbol because we
# know whether or not the symbol exists, and don't want
# to the overhead of error/duplicate checking.
# cache frequently called functions
create_symbol_func = SymbolMap.createSymbol
create_symbols_func = SymbolMap.createSymbols
alias_symbol_func = SymbolMap.alias
variable_label_pairs = []
# populate the symbol map in a single pass.
#objective_list, constraint_list, sosconstraint_list, variable_list \
# = self._populate_symbol_map(model,
# symbol_map,
# labeler,
# variable_symbol_map,
# file_determinism=file_determinism)
sortOrder = SortComponents.unsorted
if file_determinism >= 1:
sortOrder = sortOrder | SortComponents.indices
if file_determinism >= 2:
sortOrder = sortOrder | SortComponents.alphabetical
#
# Create variable symbols (and cache the block list)
#
all_blocks = []
variable_list = []
for block in model.block_data_objects(active=True,
sort=sortOrder):
all_blocks.append(block)
for vardata in block.component_data_objects(
Var,
active=True,
sort=sortOrder,
descend_into=False):
variable_list.append(vardata)
variable_label_pairs.append(
(vardata,create_symbol_func(symbol_map,
vardata,
labeler)))
variable_symbol_map.addSymbols(variable_label_pairs)
# and extract the information we'll need for rapid labeling.
object_symbol_dictionary = symbol_map.byObject
variable_symbol_dictionary = variable_symbol_map.byObject
# cache - these are called all the time.
print_expr_canonical = self._print_expr_canonical
# print the model name and the source, so we know roughly where
# it came from.
#
# NOTE: this *must* use the "\* ... *\" comment format: the GLPK
# LP parser does not correctly handle other formats (notably, "%").
output_file.write(
"\\* Source Pyomo model name=%s *\\\n\n" % (model.name,) )
#
# Objective
#
supports_quadratic_objective = \
solver_capability('quadratic_objective')
numObj = 0
onames = []
for block in all_blocks:
gen_obj_canonical_repn = \
getattr(block, "_gen_obj_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for objective_data in block.component_data_objects(
Objective,
active=True,
sort=sortOrder,
descend_into=False):
numObj += 1
onames.append(objective_data.name)
if numObj > 1:
raise ValueError(
"More than one active objective defined for input "
"model '%s'; Cannot write legal LP file\n"
"Objectives: %s" % (model.name, ' '.join(onames)))
create_symbol_func(symbol_map,
objective_data,
labeler)
symbol_map.alias(objective_data, '__default_objective__')
if objective_data.is_minimizing():
output_file.write("min \n")
else:
output_file.write("max \n")
if gen_obj_canonical_repn:
canonical_repn = \
generate_canonical_repn(objective_data.expr)
block_canonical_repn[objective_data] = canonical_repn
else:
canonical_repn = block_canonical_repn[objective_data]
degree = canonical_degree(canonical_repn)
if degree == 0:
logger.warning("Constant objective detected, replacing "
"with a placeholder to prevent solver failure.")
force_objective_constant = True
elif degree == 2:
if not supports_quadratic_objective:
raise RuntimeError(
"Selected solver is unable to handle "
"objective functions with quadratic terms. "
"Objective at issue: %s."
% objective_data.name)
elif degree != 1:
raise RuntimeError(
"Cannot write legal LP file. Objective '%s' "
"has nonlinear terms that are not quadratic."
% objective_data.name)
output_file.write(
object_symbol_dictionary[id(objective_data)]+':\n')
offset = print_expr_canonical(
canonical_repn,
output_file,
object_symbol_dictionary,
variable_symbol_dictionary,
True,
column_order,
force_objective_constant=force_objective_constant)
if numObj == 0:
raise ValueError(
"ERROR: No objectives defined for input model '%s'; "
" cannot write legal LP file" % str(model.name))
# Constraints
#
# If there are no non-trivial constraints, you'll end up with an empty
# constraint block. CPLEX is OK with this, but GLPK isn't. And
# eliminating the constraint block (i.e., the "s.t." line) causes GLPK
# to whine elsewhere. Output a warning if the constraint block is empty,
# so users can quickly determine the cause of the solve failure.
output_file.write("\n")
output_file.write("s.t.\n")
output_file.write("\n")
have_nontrivial = False
supports_quadratic_constraint = solver_capability('quadratic_constraint')
def constraint_generator():
for block in all_blocks:
gen_con_canonical_repn = \
getattr(block, "_gen_con_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for constraint_data in block.component_data_objects(
Constraint,
active=True,
sort=sortOrder,
descend_into=False):
if isinstance(constraint_data, LinearCanonicalRepn):
canonical_repn = constraint_data
else:
if gen_con_canonical_repn:
canonical_repn = generate_canonical_repn(constraint_data.body)
block_canonical_repn[constraint_data] = canonical_repn
else:
canonical_repn = block_canonical_repn[constraint_data]
yield constraint_data, canonical_repn
if row_order is not None:
sorted_constraint_list = list(constraint_generator())
sorted_constraint_list.sort(key=lambda x: row_order[x[0]])
def yield_all_constraints():
for constraint_data, canonical_repn in sorted_constraint_list:
yield constraint_data, canonical_repn
else:
yield_all_constraints = constraint_generator
# FIXME: This is a hack to get nested blocks working...
eq_string_template = "= %"+self._precision_string+'\n'
geq_string_template = ">= %"+self._precision_string+'\n\n'
leq_string_template = "<= %"+self._precision_string+'\n\n'
for constraint_data, canonical_repn in yield_all_constraints():
have_nontrivial = True
degree = canonical_degree(canonical_repn)
#
# Write constraint
#
# There are conditions, e.g., when fixing variables, under which
# a constraint block might be empty. Ignore these, for both
# practical reasons and the fact that the CPLEX LP format
# requires a variable in the constraint body. It is also
# possible that the body of the constraint consists of only a
# constant, in which case the "variable" of
if degree == 0:
if skip_trivial_constraints:
continue
elif degree == 2:
if not supports_quadratic_constraint:
raise ValueError(
"Solver unable to handle quadratic expressions. Constraint"
" at issue: '%s'" % (constraint_data.name))
elif degree != 1:
raise ValueError(
"Cannot write legal LP file. Constraint '%s' has a body "
"with nonlinear terms." % (constraint_data.name))
# Create symbol
con_symbol = create_symbol_func(symbol_map, constraint_data, labeler)
if constraint_data.equality:
label = 'c_e_' + con_symbol + '_'
alias_symbol_func(symbol_map, constraint_data, label)
output_file.write(label+':\n')
offset = print_expr_canonical(canonical_repn,
output_file,
object_symbol_dictionary,
variable_symbol_dictionary,
False,
column_order)
bound = constraint_data.lower
bound = self._get_bound(bound) - offset
output_file.write(eq_string_template
% (_no_negative_zero(bound)))
output_file.write("\n")
else:
if constraint_data.lower is not None:
if constraint_data.upper is not None:
label = 'r_l_' + con_symbol + '_'
else:
label = 'c_l_' + con_symbol + '_'
alias_symbol_func(symbol_map, constraint_data, label)
output_file.write(label+':\n')
offset = print_expr_canonical(canonical_repn,
output_file,
object_symbol_dictionary,
variable_symbol_dictionary,
False,
column_order)
bound = constraint_data.lower
bound = self._get_bound(bound) - offset
output_file.write(geq_string_template
% (_no_negative_zero(bound)))
if constraint_data.upper is not None:
if constraint_data.lower is not None:
label = 'r_u_' + con_symbol + '_'
else:
label = 'c_u_' + con_symbol + '_'
alias_symbol_func(symbol_map, constraint_data, label)
output_file.write(label+':\n')
offset = print_expr_canonical(canonical_repn,
output_file,
object_symbol_dictionary,
variable_symbol_dictionary,
False,
column_order)
bound = constraint_data.upper
bound = self._get_bound(bound) - offset
output_file.write(leq_string_template
% (_no_negative_zero(bound)))
if not have_nontrivial:
logger.warning('Empty constraint block written in LP format ' \
'- solver may error')
# the CPLEX LP format doesn't allow constants in the objective (or
# constraint body), which is a bit silly. To avoid painful
# book-keeping, we introduce the following "variable", constrained
# to the value 1. This is used when quadratic terms are present.
# worst-case, if not used, is that CPLEX easily pre-processes it out.
prefix = ""
output_file.write('%sc_e_ONE_VAR_CONSTANT: \n' % prefix)
output_file.write('%sONE_VAR_CONSTANT = 1.0\n' % prefix)
output_file.write("\n")
# SOS constraints
#
# For now, we write out SOS1 and SOS2 constraints in the cplex format
#
# All Component objects are stored in model._component, which is a
# dictionary of {class: {objName: object}}.
#
# Consider the variable X,
#
# model.X = Var(...)
#
# We print X to CPLEX format as X(i,j,k,...) where i, j, k, ... are the
# indices of X.
#
SOSlines = StringIO()
sos1 = solver_capability("sos1")
sos2 = solver_capability("sos2")
writtenSOS = False
for block in all_blocks:
for soscondata in block.component_data_objects(
SOSConstraint,
active=True,
sort=sortOrder,
descend_into=False):
create_symbol_func(symbol_map, soscondata, labeler)
level = soscondata.level
if (level == 1 and not sos1) or \
(level == 2 and not sos2) or \
(level > 2):
raise ValueError(
"Solver does not support SOS level %s constraints" % (level))
if writtenSOS == False:
SOSlines.write("SOS\n")
writtenSOS = True
# This updates the referenced_variable_ids, just in case
# there is a variable that only appears in an
# SOSConstraint, in which case this needs to be known
# before we write the "bounds" section (Cplex does not
# handle this correctly, Gurobi does)
self.printSOS(symbol_map,
labeler,
variable_symbol_map,
soscondata,
SOSlines)
#
# Bounds
#
output_file.write("bounds\n")
# Scan all variables even if we're only writing a subset of them.
# required because we don't store maps by variable type currently.
# FIXME: This is a hack to get nested blocks working...
lb_string_template = "%"+self._precision_string+" <= "
ub_string_template = " <= %"+self._precision_string+"\n"
# Track the number of integer and binary variables, so you can
# output their status later.
integer_vars = []
binary_vars = []
for vardata in variable_list:
# TODO: We could just loop over the set of items in
# self._referenced_variable_ids, except this is
# a dictionary that is hashed by id(vardata)
# which would make the bounds section
# nondeterministic (bad for unit testing)
if (not include_all_variable_bounds) and \
(id(vardata) not in self._referenced_variable_ids):
continue
if vardata.fixed:
if not output_fixed_variable_bounds:
raise ValueError(
"Encountered a fixed variable (%s) inside an active "
"objective or constraint expression on model %s, which is "
"usually indicative of a preprocessing error. Use the "
"IO-option 'output_fixed_variable_bounds=True' to suppress "
"this error and fix the variable by overwriting its bounds "
"in the LP file." % (vardata.name, model.name))
if vardata.value is None:
raise ValueError("Variable cannot be fixed to a value of None.")
vardata_lb = value(vardata.value)
vardata_ub = value(vardata.value)
else:
vardata_lb = self._get_bound(vardata.lb)
vardata_ub = self._get_bound(vardata.ub)
name_to_output = variable_symbol_dictionary[id(vardata)]
# track the number of integer and binary variables, so we know whether
# to output the general / binary sections below.
if vardata.is_integer():
integer_vars.append(name_to_output)
elif vardata.is_binary():
binary_vars.append(name_to_output)
elif not vardata.is_continuous():
raise TypeError("Invalid domain type for variable with name '%s'. "
"Variable is not continuous, integer, or binary."
% (vardata.name))
# in the CPLEX LP file format, the default variable
# bounds are 0 and +inf. These bounds are in
# conflict with Pyomo, which assumes -inf and +inf
# (which we would argue is more rational).
output_file.write(" ")
if (vardata_lb is not None) and (vardata_lb != -infinity):
output_file.write(lb_string_template
% (_no_negative_zero(vardata_lb)))
else:
output_file.write(" -inf <= ")
if name_to_output == "e":
raise ValueError(
"Attempting to write variable with name 'e' in a CPLEX LP "
"formatted file will cause a parse failure due to confusion with "
"numeric values expressed in scientific notation")
output_file.write(name_to_output)
if (vardata_ub is not None) and (vardata_ub != infinity):
output_file.write(ub_string_template
% (_no_negative_zero(vardata_ub)))
else:
output_file.write(" <= +inf\n")
if len(integer_vars) > 0:
output_file.write("general\n")
for var_name in integer_vars:
output_file.write(' %s\n' % var_name)
if len(binary_vars) > 0:
output_file.write("binary\n")
for var_name in binary_vars:
output_file.write(' %s\n' % var_name)
# Write the SOS section
output_file.write(SOSlines.getvalue())
#
# wrap-up
#
output_file.write("end\n")
# Clean up the symbol map to only contain variables referenced
# in the active constraints **Note**: warm start method may
# rely on this for choosing the set of potential warm start
# variables
vars_to_delete = set(variable_symbol_map.byObject.keys()) - \
set(self._referenced_variable_ids.keys())
sm_byObject = symbol_map.byObject
sm_bySymbol = symbol_map.bySymbol
var_sm_byObject = variable_symbol_map.byObject
for varid in vars_to_delete:
symbol = var_sm_byObject[varid]
del sm_byObject[varid]
del sm_bySymbol[symbol]
del variable_symbol_map
return symbol_map
def _populate_gurobi_instance (self, pyomo_instance):
from pyomo.core.base import Var, Objective, Constraint, SOSConstraint
from pyomo.repn import LinearCanonicalRepn, canonical_degree
try:
grbmodel = Model(name=pyomo_instance.name)
except Exception:
e = sys.exc_info()[1]
msg = 'Unable to create Gurobi model. Have you installed the Python'\
'\n bindings for Gurobi?\n\n\tError message: %s'
raise Exception(msg % e)
if self._symbolic_solver_labels:
labeler = TextLabeler()
else:
labeler = NumericLabeler('x')
# cache to avoid dictionary getitem calls in the loops below.
self_symbol_map = self._symbol_map = SymbolMap()
pyomo_instance.solutions.add_symbol_map(self_symbol_map)
self._smap_id = id(self_symbol_map)
# we use this when iterating over the constraints because it
# will have a much smaller hash table, we also use this for
# the warm start code after it is cleaned to only contain
# variables referenced in the constraints
self_variable_symbol_map = self._variable_symbol_map = SymbolMap()
var_symbol_pairs = []
# maps _VarData labels to the corresponding Gurobi variable object
pyomo_gurobi_variable_map = {}
self._referenced_variable_ids.clear()
# cache to avoid dictionary getitem calls in the loop below.
grb_infinity = GRB.INFINITY
for var_value in pyomo_instance.component_data_objects(Var, active=True):
lb = -grb_infinity
ub = grb_infinity
if (var_value.lb is not None) and (var_value.lb != -infinity):
lb = value(var_value.lb)
if (var_value.ub is not None) and (var_value.ub != infinity):
ub = value(var_value.ub)
# _VarValue objects will not be in the symbol map yet, so
# avoid some checks.
var_value_label = self_symbol_map.createSymbol(var_value, labeler)
var_symbol_pairs.append((var_value, var_value_label))
# be sure to impart the integer and binary nature of any variables
if var_value.is_integer():
var_type = GRB.INTEGER
elif var_value.is_binary():
var_type = GRB.BINARY
elif var_value.is_continuous():
var_type = GRB.CONTINUOUS
else:
raise TypeError("Invalid domain type for variable with name '%s'. "
"Variable is not continuous, integer, or binary.")
pyomo_gurobi_variable_map[var_value_label] = \
grbmodel.addVar(lb=lb, \
ub=ub, \
vtype=var_type, \
name=var_value_label)
self_variable_symbol_map.addSymbols(var_symbol_pairs)
grbmodel.update()
# The next loop collects the following component types from the model:
# - SOSConstraint
# - Objective
# - Constraint
sos1 = self._capabilities.sos1
sos2 = self._capabilities.sos2
modelSOS = ModelSOS()
objective_cntr = 0
# Track the range constraints and their associated variables added by gurobi
self._last_native_var_idx = grbmodel.NumVars-1
range_var_idx = grbmodel.NumVars
_self_range_con_var_pairs = self._range_con_var_pairs = []
for block in pyomo_instance.block_data_objects(active=True):
gen_obj_canonical_repn = \
getattr(block, "_gen_obj_canonical_repn", True)
gen_con_canonical_repn = \
getattr(block, "_gen_con_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
# SOSConstraints
for soscondata in block.component_data_objects(SOSConstraint,
active=True,
descend_into=False):
level = soscondata.level
if (level == 1 and not sos1) or \
(level == 2 and not sos2) or \
(level > 2):
raise RuntimeError(
"Solver does not support SOS level %s constraints" % (level,))
modelSOS.count_constraint(self_symbol_map,
labeler,
self_variable_symbol_map,
pyomo_gurobi_variable_map,
soscondata)
# Objective
for obj_data in block.component_data_objects(Objective,
active=True,
descend_into=False):
if objective_cntr > 1:
raise ValueError(
"Multiple active objectives found on Pyomo instance '%s'. "
"Solver '%s' will only handle a single active objective" \
% (pyomo_instance.cname(True), self.type))
sense = GRB_MIN if (obj_data.is_minimizing()) else GRB_MAX
grbmodel.ModelSense = sense
obj_expr = LinExpr()
if gen_obj_canonical_repn:
obj_repn = generate_canonical_repn(obj_data.expr)
block_canonical_repn[obj_data] = obj_repn
else:
obj_repn = block_canonical_repn[obj_data]
if isinstance(obj_repn, LinearCanonicalRepn):
if obj_repn.constant != None:
obj_expr.addConstant(obj_repn.constant)
if obj_repn.linear != None:
for i in xrange(len(obj_repn.linear)):
var_coefficient = obj_repn.linear[i]
var_value = obj_repn.variables[i]
self._referenced_variable_ids.add(id(var_value))
label = self_variable_symbol_map.getSymbol(var_value)
obj_expr.addTerms(var_coefficient,
pyomo_gurobi_variable_map[label])
else:
if 0 in obj_repn: # constant term
obj_expr.addConstant(obj_repn[0][None])
if 1 in obj_repn: # first-order terms
hash_to_variable_map = obj_repn[-1]
for var_hash, var_coefficient in iteritems(obj_repn[1]):
vardata = hash_to_variable_map[var_hash]
self._referenced_variable_ids.add(id(vardata))
label = self_variable_symbol_map.getSymbol(vardata)
obj_expr.addTerms(var_coefficient,
pyomo_gurobi_variable_map[label])
if 2 in obj_repn:
obj_expr = QuadExpr(obj_expr)
hash_to_variable_map = obj_repn[-1]
for quad_repn, coef in iteritems(obj_repn[2]):
gurobi_expr = QuadExpr(coef)
for var_hash, exponent in iteritems(quad_repn):
vardata = hash_to_variable_map[var_hash]
self._referenced_variable_ids.add(id(vardata))
gurobi_var = pyomo_gurobi_variable_map\
[self_variable_symbol_map.\
getSymbol(vardata)]
gurobi_expr *= gurobi_var
if exponent == 2:
gurobi_expr *= gurobi_var
obj_expr += gurobi_expr
degree = canonical_degree(obj_repn)
if (degree is None) or (degree > 2):
raise ValueError(
"gurobi_direct plugin does not support general nonlinear "
"objective expressions (only linear or quadratic).\n"
"Objective: %s" % (obj_data.cname(True)))
# need to cache the objective label, because the
# GUROBI python interface doesn't track this.
# _ObjectiveData objects will not be in the symbol map
# yet, so avoid some checks.
self._objective_label = \
self_symbol_map.createSymbol(obj_data, labeler)
grbmodel.setObjective(obj_expr, sense=sense)
# Constraint
for constraint_data in block.component_data_objects(Constraint,
active=True,
descend_into=False):
if (constraint_data.lower is None) and \
(constraint_data.upper is None):
continue # not binding at all, don't bother
con_repn = None
if isinstance(constraint_data, LinearCanonicalRepn):
con_repn = constraint_data
else:
if gen_con_canonical_repn:
con_repn = generate_canonical_repn(constraint_data.body)
block_canonical_repn[constraint_data] = con_repn
else:
con_repn = block_canonical_repn[constraint_data]
offset = 0.0
# _ConstraintData objects will not be in the symbol
# map yet, so avoid some checks.
constraint_label = \
self_symbol_map.createSymbol(constraint_data, labeler)
trivial = False
if isinstance(con_repn, LinearCanonicalRepn):
#
# optimization (these might be generated on the fly)
#
constant = con_repn.constant
coefficients = con_repn.linear
variables = con_repn.variables
if constant is not None:
offset = constant
expr = LinExpr() + offset
if coefficients is not None:
linear_coefs = list()
linear_vars = list()
for i in xrange(len(coefficients)):
var_coefficient = coefficients[i]
var_value = variables[i]
self._referenced_variable_ids.add(id(var_value))
label = self_variable_symbol_map.getSymbol(var_value)
linear_coefs.append(var_coefficient)
linear_vars.append(pyomo_gurobi_variable_map[label])
expr += LinExpr(linear_coefs, linear_vars)
else:
trivial = True
else:
if 0 in con_repn:
offset = con_repn[0][None]
expr = LinExpr() + offset
if 1 in con_repn: # first-order terms
linear_coefs = list()
linear_vars = list()
hash_to_variable_map = con_repn[-1]
for var_hash, var_coefficient in iteritems(con_repn[1]):
var = hash_to_variable_map[var_hash]
self._referenced_variable_ids.add(id(var))
label = self_variable_symbol_map.getSymbol(var)
linear_coefs.append( var_coefficient )
linear_vars.append( pyomo_gurobi_variable_map[label] )
expr += LinExpr(linear_coefs, linear_vars)
if 2 in con_repn: # quadratic constraint
if _GUROBI_VERSION_MAJOR < 5:
raise ValueError(
"The gurobi_direct plugin does not handle quadratic "
"constraint expressions for Gurobi major versions "
"< 5. Current version: Gurobi %s.%s%s"
% (gurobi.version()))
expr = QuadExpr(expr)
hash_to_variable_map = con_repn[-1]
for quad_repn, coef in iteritems(con_repn[2]):
gurobi_expr = QuadExpr(coef)
for var_hash, exponent in iteritems(quad_repn):
vardata = hash_to_variable_map[var_hash]
self._referenced_variable_ids.add(id(vardata))
gurobi_var = pyomo_gurobi_variable_map\
[self_variable_symbol_map.\
getSymbol(vardata)]
gurobi_expr *= gurobi_var
if exponent == 2:
gurobi_expr *= gurobi_var
expr += gurobi_expr
degree = canonical_degree(con_repn)
if (degree is None) or (degree > 2):
raise ValueError(
"gurobi_direct plugin does not support general nonlinear "
"constraint expressions (only linear or quadratic).\n"
"Constraint: %s" % (constraint_data.cname(True)))
if (not trivial) or (not self._skip_trivial_constraints):
if constraint_data.equality:
sense = GRB.EQUAL
bound = self._get_bound(constraint_data.lower)
grbmodel.addConstr(lhs=expr,
sense=sense,
rhs=bound,
name=constraint_label)
else:
# L <= body <= U
if (constraint_data.upper is not None) and \
(constraint_data.lower is not None):
grb_con = grbmodel.addRange(
expr,
self._get_bound(constraint_data.lower),
self._get_bound(constraint_data.upper),
constraint_label)
_self_range_con_var_pairs.append((grb_con,range_var_idx))
range_var_idx += 1
# body <= U
elif constraint_data.upper is not None:
bound = self._get_bound(constraint_data.upper)
if bound < float('inf'):
grbmodel.addConstr(
lhs=expr,
sense=GRB.LESS_EQUAL,
rhs=bound,
name=constraint_label
)
# L <= body
else:
bound = self._get_bound(constraint_data.lower)
if bound > -float('inf'):
grbmodel.addConstr(
lhs=expr,
sense=GRB.GREATER_EQUAL,
rhs=bound,
name=constraint_label
)
if modelSOS.sosType:
for key in modelSOS.sosType:
grbmodel.addSOS(modelSOS.sosType[key], \
modelSOS.varnames[key], \
modelSOS.weights[key] )
self._referenced_variable_ids.update(modelSOS.varids[key])
for var_id in self._referenced_variable_ids:
varname = self._variable_symbol_map.byObject[var_id]
vardata = self._variable_symbol_map.bySymbol[varname]()
if vardata.fixed:
if not self._output_fixed_variable_bounds:
raise ValueError("Encountered a fixed variable (%s) inside an active objective "
"or constraint expression on model %s, which is usually indicative of "
"a preprocessing error. Use the IO-option 'output_fixed_variable_bounds=True' "
"to suppress this error and fix the variable by overwriting its bounds in "
"the Gurobi instance."
% (vardata.cname(True),pyomo_instance.cname(True),))
grbvar = pyomo_gurobi_variable_map[varname]
grbvar.setAttr(GRB.Attr.UB, vardata.value)
grbvar.setAttr(GRB.Attr.LB, vardata.value)
grbmodel.update()
self._gurobi_instance = grbmodel
self._pyomo_gurobi_variable_map = pyomo_gurobi_variable_map
def _replace_bilinear(self, expr, instance):
idMap = {}
terms = generate_canonical_repn(expr, idMap=idMap)
# Constant
if 0 in terms:
e = terms[0][None]
else:
e = 0
# Linear terms
if 1 in terms:
for key in terms[1]:
e += terms[1][key] * idMap[key]
# Quadratic terms
if 2 in terms:
for key in terms[2]:
vars = []
for v in key:
vars.append(idMap[v])
coef = terms[2][key]
#
if isinstance(vars[0].domain, BooleanSet):
instance.bilinear_data_.vlist_boolean.append(vars[0])
v = instance.bilinear_data_.vlist.add()
bounds = vars[1].bounds
v.setlb(bounds[0])
v.setub(bounds[1])
id = len(instance.bilinear_data_.vlist)
instance.bilinear_data_.index.add(id)
# First disjunct
d0 = instance.bilinear_data_.disjuncts_[id,0]
d0.c1 = Constraint(expr=vars[0] == 1)
d0.c2 = Constraint(expr=v == coef*vars[1])
# Second disjunct
d1 = instance.bilinear_data_.disjuncts_[id,1]
d1.c1 = Constraint(expr=vars[0] == 0)
d1.c2 = Constraint(expr=v == 0)
# Disjunction
instance.bilinear_data_.disjunction_data[id] = [instance.bilinear_data_.disjuncts_[id,0], instance.bilinear_data_.disjuncts_[id,1]]
instance.bilinear_data_.disjunction_data[id] = [instance.bilinear_data_.disjuncts_[id,0], instance.bilinear_data_.disjuncts_[id,1]]
# The disjunctive variable is the expression
e += v
#
elif isinstance(vars[1].domain, BooleanSet):
instance.bilinear_data_.vlist_boolean.append(vars[1])
v = instance.bilinear_data_.vlist.add()
bounds = vars[0].bounds
v.setlb(bounds[0])
v.setub(bounds[1])
id = len(instance.bilinear_data_.vlist)
instance.bilinear_data_.index.add(id)
# First disjunct
d0 = instance.bilinear_data_.disjuncts_[id,0]
d0.c1 = Constraint(expr=vars[1] == 1)
d0.c2 = Constraint(expr=v == coef*vars[0])
# Second disjunct
d1 = instance.bilinear_data_.disjuncts_[id,1]
d1.c1 = Constraint(expr=vars[1] == 0)
d1.c2 = Constraint(expr=v == 0)
# Disjunction
instance.bilinear_data_.disjunction_data[id] = [instance.bilinear_data_.disjuncts_[id,0], instance.bilinear_data_.disjuncts_[id,1]]
# The disjunctive variable is the expression
e += v
else:
# If neither variable is boolean, just reinsert the original bilinear term
e += coef*vars[0]*vars[1]
#
return e
def _xform_constraint(self, _name, constraint, varMap, disjunct, block):
lin_body_map = getattr(block, "lin_body", None)
for cname, c in iteritems(constraint._data):
name = _name + ('.%s' % (cname, ) if cname else '')
if (not lin_body_map is None) and (
not lin_body_map.get(c) is None):
raise GDP_Error('GDP(cHull) cannot process linear ' \
'constraint bodies (yet) (found at ' + name + ').')
constant = 0
try:
cannonical = generate_canonical_repn(c.body)
if isinstance(cannonical, LinearCanonicalRepn):
NL = False
else:
NL = canonical_is_nonlinear(cannonical)
except:
NL = True
# We need to evaluate teh expression at the origin *before*
# we substitute the expression variables with the
# disaggregated variables
if NL and self._mode == NL_Mode_FurmanSawayaGrossmann:
h_0 = value(
self._eval_at_origin(NL, c.body.clone(),
disjunct.indicator_var, varMap))
expr = self._var_subst(NL, c.body, disjunct.indicator_var, varMap)
if NL:
y = disjunct.indicator_var
if self._mode == NL_Mode_LeeGrossmann:
expr = expr * y
elif self._mode == NL_Mode_GrossmannLee:
expr = (y + EPS) * expr
elif self._mode == NL_Mode_FurmanSawayaGrossmann:
expr = ((1 - EPS) * y + EPS) * expr - EPS * h_0 * (1 - y)
else:
raise RuntimeError("Unknown NL CHull mode")
else:
# We need to make sure to pull out the constant terms
# from the expression and put them into the lb/ub
if cannonical.constant == None:
constant = 0
else:
constant = cannonical.constant
if c.lower is not None:
if __debug__ and logger.isEnabledFor(logging.DEBUG):
logger.debug(
"GDP(cHull): Promoting constraint " +
"'%s' as '%s_lo'", name, name)
bound = c.lower() - constant
if bound != 0:
newC = Constraint( expr = bound*disjunct.indicator_var \
<= expr - constant )
else:
newC = Constraint(expr=bound <= expr - constant)
block.add_component(name + "_lo", newC)
newC.construct()
if c.upper is not None:
if __debug__ and logger.isEnabledFor(logging.DEBUG):
logger.debug(
"GDP(cHull): Promoting constraint " +
"'%s' as '%s_hi'", name, name)
bound = c.upper() - constant
if bound != 0:
newC = Constraint( expr = expr - constant <= \
bound*disjunct.indicator_var )
else:
newC = Constraint(expr=expr - constant <= bound)
block.add_component(name + "_hi", newC)
newC.construct()
def _populate_gurobi_instance(self, pyomo_instance):
from pyomo.core.base import Var, Objective, Constraint, SOSConstraint
from pyomo.repn import LinearCanonicalRepn, canonical_degree
try:
grbmodel = Model(name=pyomo_instance.name)
except Exception:
e = sys.exc_info()[1]
msg = 'Unable to create Gurobi model. Have you installed the Python'\
'\n bindings for Gurobi?\n\n\tError message: %s'
raise Exception(msg % e)
if self._symbolic_solver_labels:
labeler = TextLabeler()
else:
labeler = NumericLabeler('x')
# cache to avoid dictionary getitem calls in the loops below.
self_symbol_map = self._symbol_map = SymbolMap()
pyomo_instance.solutions.add_symbol_map(self_symbol_map)
self._smap_id = id(self_symbol_map)
# we use this when iterating over the constraints because it
# will have a much smaller hash table, we also use this for
# the warm start code after it is cleaned to only contain
# variables referenced in the constraints
self_variable_symbol_map = self._variable_symbol_map = SymbolMap()
var_symbol_pairs = []
# maps _VarData labels to the corresponding Gurobi variable object
pyomo_gurobi_variable_map = {}
self._referenced_variable_ids.clear()
# cache to avoid dictionary getitem calls in the loop below.
grb_infinity = GRB.INFINITY
for var_value in pyomo_instance.component_data_objects(Var,
active=True):
lb = -grb_infinity
ub = grb_infinity
if (var_value.lb is not None) and (var_value.lb != -infinity):
lb = value(var_value.lb)
if (var_value.ub is not None) and (var_value.ub != infinity):
ub = value(var_value.ub)
# _VarValue objects will not be in the symbol map yet, so
# avoid some checks.
var_value_label = self_symbol_map.createSymbol(var_value, labeler)
var_symbol_pairs.append((var_value, var_value_label))
# be sure to impart the integer and binary nature of any variables
if var_value.is_integer():
var_type = GRB.INTEGER
elif var_value.is_binary():
var_type = GRB.BINARY
elif var_value.is_continuous():
var_type = GRB.CONTINUOUS
else:
raise TypeError(
"Invalid domain type for variable with name '%s'. "
"Variable is not continuous, integer, or binary.")
pyomo_gurobi_variable_map[var_value_label] = \
grbmodel.addVar(lb=lb, \
ub=ub, \
vtype=var_type, \
name=var_value_label)
self_variable_symbol_map.addSymbols(var_symbol_pairs)
grbmodel.update()
# The next loop collects the following component types from the model:
# - SOSConstraint
# - Objective
# - Constraint
sos1 = self._capabilities.sos1
sos2 = self._capabilities.sos2
modelSOS = ModelSOS()
objective_cntr = 0
# Track the range constraints and their associated variables added by gurobi
self._last_native_var_idx = grbmodel.NumVars - 1
range_var_idx = grbmodel.NumVars
_self_range_con_var_pairs = self._range_con_var_pairs = []
for block in pyomo_instance.block_data_objects(active=True):
gen_obj_canonical_repn = \
getattr(block, "_gen_obj_canonical_repn", True)
gen_con_canonical_repn = \
getattr(block, "_gen_con_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block, '_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
# SOSConstraints
for soscondata in block.component_data_objects(SOSConstraint,
active=True,
descend_into=False):
level = soscondata.level
if (level == 1 and not sos1) or \
(level == 2 and not sos2) or \
(level > 2):
raise RuntimeError(
"Solver does not support SOS level %s constraints" %
(level, ))
modelSOS.count_constraint(self_symbol_map, labeler,
self_variable_symbol_map,
pyomo_gurobi_variable_map,
soscondata)
# Objective
for obj_data in block.component_data_objects(Objective,
active=True,
descend_into=False):
if objective_cntr > 1:
raise ValueError(
"Multiple active objectives found on Pyomo instance '%s'. "
"Solver '%s' will only handle a single active objective" \
% (pyomo_instance.cname(True), self.type))
sense = GRB_MIN if (obj_data.is_minimizing()) else GRB_MAX
grbmodel.ModelSense = sense
obj_expr = LinExpr()
if gen_obj_canonical_repn:
obj_repn = generate_canonical_repn(obj_data.expr)
block_canonical_repn[obj_data] = obj_repn
else:
obj_repn = block_canonical_repn[obj_data]
if isinstance(obj_repn, LinearCanonicalRepn):
if obj_repn.constant != None:
obj_expr.addConstant(obj_repn.constant)
if obj_repn.linear != None:
for i in xrange(len(obj_repn.linear)):
var_coefficient = obj_repn.linear[i]
var_value = obj_repn.variables[i]
self._referenced_variable_ids.add(id(var_value))
label = self_variable_symbol_map.getSymbol(
var_value)
obj_expr.addTerms(var_coefficient,
pyomo_gurobi_variable_map[label])
else:
if 0 in obj_repn: # constant term
obj_expr.addConstant(obj_repn[0][None])
if 1 in obj_repn: # first-order terms
hash_to_variable_map = obj_repn[-1]
for var_hash, var_coefficient in iteritems(
obj_repn[1]):
vardata = hash_to_variable_map[var_hash]
self._referenced_variable_ids.add(id(vardata))
label = self_variable_symbol_map.getSymbol(vardata)
obj_expr.addTerms(var_coefficient,
pyomo_gurobi_variable_map[label])
if 2 in obj_repn:
obj_expr = QuadExpr(obj_expr)
hash_to_variable_map = obj_repn[-1]
for quad_repn, coef in iteritems(obj_repn[2]):
gurobi_expr = QuadExpr(coef)
for var_hash, exponent in iteritems(quad_repn):
vardata = hash_to_variable_map[var_hash]
self._referenced_variable_ids.add(id(vardata))
gurobi_var = pyomo_gurobi_variable_map\
[self_variable_symbol_map.\
getSymbol(vardata)]
gurobi_expr *= gurobi_var
if exponent == 2:
gurobi_expr *= gurobi_var
obj_expr += gurobi_expr
degree = canonical_degree(obj_repn)
if (degree is None) or (degree > 2):
raise ValueError(
"gurobi_direct plugin does not support general nonlinear "
"objective expressions (only linear or quadratic).\n"
"Objective: %s" % (obj_data.cname(True)))
# need to cache the objective label, because the
# GUROBI python interface doesn't track this.
# _ObjectiveData objects will not be in the symbol map
# yet, so avoid some checks.
self._objective_label = \
self_symbol_map.createSymbol(obj_data, labeler)
grbmodel.setObjective(obj_expr, sense=sense)
# Constraint
for constraint_data in block.component_data_objects(
Constraint, active=True, descend_into=False):
if (constraint_data.lower is None) and \
(constraint_data.upper is None):
continue # not binding at all, don't bother
con_repn = None
if isinstance(constraint_data, LinearCanonicalRepn):
con_repn = constraint_data
else:
if gen_con_canonical_repn:
con_repn = generate_canonical_repn(
constraint_data.body)
block_canonical_repn[constraint_data] = con_repn
else:
con_repn = block_canonical_repn[constraint_data]
offset = 0.0
# _ConstraintData objects will not be in the symbol
# map yet, so avoid some checks.
constraint_label = \
self_symbol_map.createSymbol(constraint_data, labeler)
trivial = False
if isinstance(con_repn, LinearCanonicalRepn):
#
# optimization (these might be generated on the fly)
#
constant = con_repn.constant
coefficients = con_repn.linear
variables = con_repn.variables
if constant is not None:
offset = constant
expr = LinExpr() + offset
if coefficients is not None:
linear_coefs = list()
linear_vars = list()
for i in xrange(len(coefficients)):
var_coefficient = coefficients[i]
var_value = variables[i]
self._referenced_variable_ids.add(id(var_value))
label = self_variable_symbol_map.getSymbol(
var_value)
linear_coefs.append(var_coefficient)
linear_vars.append(
pyomo_gurobi_variable_map[label])
expr += LinExpr(linear_coefs, linear_vars)
else:
trivial = True
else:
if 0 in con_repn:
offset = con_repn[0][None]
expr = LinExpr() + offset
if 1 in con_repn: # first-order terms
linear_coefs = list()
linear_vars = list()
hash_to_variable_map = con_repn[-1]
for var_hash, var_coefficient in iteritems(
con_repn[1]):
var = hash_to_variable_map[var_hash]
self._referenced_variable_ids.add(id(var))
label = self_variable_symbol_map.getSymbol(var)
linear_coefs.append(var_coefficient)
linear_vars.append(
pyomo_gurobi_variable_map[label])
expr += LinExpr(linear_coefs, linear_vars)
if 2 in con_repn: # quadratic constraint
if _GUROBI_VERSION_MAJOR < 5:
raise ValueError(
"The gurobi_direct plugin does not handle quadratic "
"constraint expressions for Gurobi major versions "
"< 5. Current version: Gurobi %s.%s%s" %
(gurobi.version()))
expr = QuadExpr(expr)
hash_to_variable_map = con_repn[-1]
for quad_repn, coef in iteritems(con_repn[2]):
gurobi_expr = QuadExpr(coef)
for var_hash, exponent in iteritems(quad_repn):
vardata = hash_to_variable_map[var_hash]
self._referenced_variable_ids.add(id(vardata))
gurobi_var = pyomo_gurobi_variable_map\
[self_variable_symbol_map.\
getSymbol(vardata)]
gurobi_expr *= gurobi_var
if exponent == 2:
gurobi_expr *= gurobi_var
expr += gurobi_expr
degree = canonical_degree(con_repn)
if (degree is None) or (degree > 2):
raise ValueError(
"gurobi_direct plugin does not support general nonlinear "
"constraint expressions (only linear or quadratic).\n"
"Constraint: %s" % (constraint_data.cname(True)))
if (not trivial) or (not self._skip_trivial_constraints):
if constraint_data.equality:
sense = GRB.EQUAL
bound = self._get_bound(constraint_data.lower)
grbmodel.addConstr(lhs=expr,
sense=sense,
rhs=bound,
name=constraint_label)
else:
# L <= body <= U
if (constraint_data.upper is not None) and \
(constraint_data.lower is not None):
grb_con = grbmodel.addRange(
expr, self._get_bound(constraint_data.lower),
self._get_bound(constraint_data.upper),
constraint_label)
_self_range_con_var_pairs.append(
(grb_con, range_var_idx))
range_var_idx += 1
# body <= U
elif constraint_data.upper is not None:
bound = self._get_bound(constraint_data.upper)
if bound < float('inf'):
grbmodel.addConstr(lhs=expr,
sense=GRB.LESS_EQUAL,
rhs=bound,
name=constraint_label)
# L <= body
else:
bound = self._get_bound(constraint_data.lower)
if bound > -float('inf'):
grbmodel.addConstr(lhs=expr,
sense=GRB.GREATER_EQUAL,
rhs=bound,
name=constraint_label)
if modelSOS.sosType:
for key in modelSOS.sosType:
grbmodel.addSOS(modelSOS.sosType[key], \
modelSOS.varnames[key], \
modelSOS.weights[key] )
self._referenced_variable_ids.update(modelSOS.varids[key])
for var_id in self._referenced_variable_ids:
varname = self._variable_symbol_map.byObject[var_id]
vardata = self._variable_symbol_map.bySymbol[varname]()
if vardata.fixed:
if not self._output_fixed_variable_bounds:
raise ValueError(
"Encountered a fixed variable (%s) inside an active objective "
"or constraint expression on model %s, which is usually indicative of "
"a preprocessing error. Use the IO-option 'output_fixed_variable_bounds=True' "
"to suppress this error and fix the variable by overwriting its bounds in "
"the Gurobi instance." % (
vardata.cname(True),
pyomo_instance.cname(True),
))
grbvar = pyomo_gurobi_variable_map[varname]
grbvar.setAttr(GRB.Attr.UB, vardata.value)
grbvar.setAttr(GRB.Attr.LB, vardata.value)
grbmodel.update()
self._gurobi_instance = grbmodel
self._pyomo_gurobi_variable_map = pyomo_gurobi_variable_map
def _print_model_MPS(self,
model,
output_file,
solver_capability,
labeler,
output_fixed_variable_bounds=False,
file_determinism=1,
row_order=None,
column_order=None,
skip_trivial_constraints=False,
force_objective_constant=False,
include_all_variable_bounds=False,
skip_objective_sense=False):
symbol_map = SymbolMap()
variable_symbol_map = SymbolMap()
# NOTE: we use createSymbol instead of getSymbol because we
# know whether or not the symbol exists, and don't want
# to the overhead of error/duplicate checking.
# cache frequently called functions
extract_variable_coefficients = self._extract_variable_coefficients
create_symbol_func = SymbolMap.createSymbol
create_symbols_func = SymbolMap.createSymbols
alias_symbol_func = SymbolMap.alias
variable_label_pairs = []
sortOrder = SortComponents.unsorted
if file_determinism >= 1:
sortOrder = sortOrder | SortComponents.indices
if file_determinism >= 2:
sortOrder = sortOrder | SortComponents.alphabetical
#
# Create variable symbols (and cache the block list)
#
all_blocks = []
variable_list = []
for block in model.block_data_objects(active=True,
sort=sortOrder):
all_blocks.append(block)
for vardata in block.component_data_objects(
Var,
active=True,
sort=sortOrder,
descend_into=False):
variable_list.append(vardata)
variable_label_pairs.append(
(vardata,create_symbol_func(symbol_map,
vardata,
labeler)))
variable_symbol_map.addSymbols(variable_label_pairs)
# and extract the information we'll need for rapid labeling.
object_symbol_dictionary = symbol_map.byObject
variable_symbol_dictionary = variable_symbol_map.byObject
# sort the variable ordering by the user
# column_order ComponentMap
if column_order is not None:
variable_list.sort(key=lambda _x: column_order[_x])
# prepare to hold the sparse columns
variable_to_column = ComponentMap(
(vardata, i) for i, vardata in enumerate(variable_list))
# add one position for ONE_VAR_CONSTANT
column_data = [[] for i in xrange(len(variable_list)+1)]
quadobj_data = []
quadmatrix_data = []
# constraint rhs
rhs_data = []
# print the model name and the source, so we know
# roughly where
output_file.write("* Source: Pyomo MPS Writer\n")
output_file.write("* Format: Free MPS\n")
output_file.write("*\n")
output_file.write("NAME %s\n" % (model.name,))
#
# ROWS section
#
objective_label = None
numObj = 0
onames = []
for block in all_blocks:
gen_obj_canonical_repn = \
getattr(block, "_gen_obj_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for objective_data in block.component_data_objects(
Objective,
active=True,
sort=sortOrder,
descend_into=False):
numObj += 1
onames.append(objective_data.cname())
if numObj > 1:
raise ValueError(
"More than one active objective defined for input "
"model '%s'; Cannot write legal MPS file\n"
"Objectives: %s" % (model.cname(True), ' '.join(onames)))
objective_label = create_symbol_func(symbol_map,
objective_data,
labeler)
symbol_map.alias(objective_data, '__default_objective__')
if not skip_objective_sense:
output_file.write("OBJSENSE\n")
if objective_data.is_minimizing():
output_file.write(" MIN\n")
else:
output_file.write(" MAX\n")
# This section is not recognized by the COIN-OR
# MPS reader
#output_file.write("OBJNAME\n")
#output_file.write(" %s\n" % (objective_label))
output_file.write("ROWS\n")
output_file.write(" N %s\n" % (objective_label))
if gen_obj_canonical_repn:
canonical_repn = \
generate_canonical_repn(objective_data.expr)
block_canonical_repn[objective_data] = canonical_repn
else:
canonical_repn = block_canonical_repn[objective_data]
degree = canonical_degree(canonical_repn)
if degree == 0:
print("Warning: Constant objective detected, replacing "
"with a placeholder to prevent solver failure.")
force_objective_constant = True
elif (degree != 1) and (degree != 2):
raise RuntimeError(
"Cannot write legal MPS file. Objective '%s' "
"has nonlinear terms that are not quadratic."
% objective_data.cname(True))
constant = extract_variable_coefficients(
objective_label,
canonical_repn,
column_data,
quadobj_data,
variable_to_column)
if force_objective_constant or (constant != 0.0):
# ONE_VAR_CONSTANT
column_data[-1].append((objective_label, constant))
if numObj == 0:
raise ValueError(
"Cannot write legal MPS file: No objective defined "
"for input model '%s'." % str(model))
assert objective_label is not None
# Constraints
def constraint_generator():
for block in all_blocks:
gen_con_canonical_repn = \
getattr(block, "_gen_con_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for constraint_data in block.component_data_objects(
Constraint,
active=True,
sort=sortOrder,
descend_into=False):
if isinstance(constraint_data, LinearCanonicalRepn):
canonical_repn = constraint_data
else:
if gen_con_canonical_repn:
canonical_repn = generate_canonical_repn(
constraint_data.body)
block_canonical_repn[constraint_data] = canonical_repn
else:
canonical_repn = block_canonical_repn[constraint_data]
yield constraint_data, canonical_repn
if row_order is not None:
sorted_constraint_list = list(constraint_generator())
sorted_constraint_list.sort(key=lambda x: row_order[x[0]])
def yield_all_constraints():
for constraint_data, canonical_repn in sorted_constraint_list:
yield constraint_data, canonical_repn
else:
yield_all_constraints = constraint_generator
for constraint_data, canonical_repn in yield_all_constraints():
degree = canonical_degree(canonical_repn)
# Write constraint
if degree == 0:
if skip_trivial_constraints:
continue
elif (degree != 1) and (degree != 2):
raise RuntimeError(
"Cannot write legal MPS file. Constraint '%s' "
"has nonlinear terms that are not quadratic."
% constraint_data.cname(True))
# Create symbol
con_symbol = create_symbol_func(symbol_map,
constraint_data,
labeler)
if constraint_data.equality:
label = 'c_e_' + con_symbol + '_'
alias_symbol_func(symbol_map, constraint_data, label)
output_file.write(" E %s\n" % (label))
offset = extract_variable_coefficients(
label,
canonical_repn,
column_data,
quadmatrix_data,
variable_to_column)
bound = constraint_data.lower
bound = self._get_bound(bound) - offset
rhs_data.append((label, bound))
else:
if constraint_data.lower is not None:
if constraint_data.upper is not None:
label = 'r_l_' + con_symbol + '_'
else:
label = 'c_l_' + con_symbol + '_'
alias_symbol_func(symbol_map, constraint_data, label)
output_file.write(" G %s\n" % (label))
offset = extract_variable_coefficients(
label,
canonical_repn,
column_data,
quadmatrix_data,
variable_to_column)
bound = constraint_data.lower
bound = self._get_bound(bound) - offset
rhs_data.append((label, bound))
if constraint_data.upper is not None:
if constraint_data.lower is not None:
label = 'r_u_' + con_symbol + '_'
else:
label = 'c_u_' + con_symbol + '_'
alias_symbol_func(symbol_map, constraint_data, label)
output_file.write(" L %s\n" % (label))
offset = extract_variable_coefficients(
label,
canonical_repn,
column_data,
quadmatrix_data,
variable_to_column)
bound = constraint_data.upper
bound = self._get_bound(bound) - offset
rhs_data.append((label, bound))
if len(column_data[-1]) > 0:
# ONE_VAR_CONSTANT = 1
output_file.write(" E c_e_ONE_VAR_CONSTANT\n")
column_data[-1].append(("c_e_ONE_VAR_CONSTANT",1))
rhs_data.append(("c_e_ONE_VAR_CONSTANT",1))
#
# COLUMNS section
#
column_template = " %s %s %"+self._precision_string+"\n"
output_file.write("COLUMNS\n")
cnt = 0
for vardata in variable_list:
col_entries = column_data[variable_to_column[vardata]]
cnt += 1
if len(col_entries) > 0:
var_label = variable_symbol_dictionary[id(vardata)]
for i, (row_label, coef) in enumerate(col_entries):
output_file.write(column_template % (var_label,
row_label,
coef))
elif include_all_variable_bounds:
# the column is empty, so add a (0 * var)
# term to the objective
# * Note that some solvers (e.g., Gurobi)
# will accept an empty column as a line
# with just the column name. This doesn't
# seem to work for CPLEX 12.6, so I am
# doing it this way so that it will work for both
var_label = variable_symbol_dictionary[id(vardata)]
output_file.write(column_template % (var_label,
objective_label,
0))
assert cnt == len(column_data)-1
if len(column_data[-1]) > 0:
col_entries = column_data[-1]
var_label = "ONE_VAR_CONSTANT"
for i, (row_label, coef) in enumerate(col_entries):
output_file.write(column_template % (var_label,
row_label,
coef))
#
# RHS section
#
rhs_template = " RHS %s %"+self._precision_string+"\n"
output_file.write("RHS\n")
for i, (row_label, rhs) in enumerate(rhs_data):
output_file.write(rhs_template % (row_label, rhs))
# SOS constraints
SOSlines = StringIO()
sos1 = solver_capability("sos1")
sos2 = solver_capability("sos2")
for block in all_blocks:
for soscondata in block.component_data_objects(
SOSConstraint,
active=True,
sort=sortOrder,
descend_into=False):
create_symbol_func(symbol_map, soscondata, labeler)
level = soscondata.level
if (level == 1 and not sos1) or \
(level == 2 and not sos2) or \
(level > 2):
raise ValueError(
"Solver does not support SOS level %s constraints" % (level))
# This updates the referenced_variable_ids, just in case
# there is a variable that only appears in an
# SOSConstraint, in which case this needs to be known
# before we write the "bounds" section (Cplex does not
# handle this correctly, Gurobi does)
self._printSOS(symbol_map,
labeler,
variable_symbol_map,
soscondata,
SOSlines)
#
# BOUNDS section
#
entry_template = "%s %"+self._precision_string+"\n"
output_file.write("BOUNDS\n")
for vardata in variable_list:
if include_all_variable_bounds or \
(id(vardata) in self._referenced_variable_ids):
var_label = variable_symbol_dictionary[id(vardata)]
if vardata.fixed:
if not output_fixed_variable_bounds:
raise ValueError(
"Encountered a fixed variable (%s) inside an active "
"objective or constraint expression on model %s, which is "
"usually indicative of a preprocessing error. Use the "
"IO-option 'output_fixed_variable_bounds=True' to suppress "
"this error and fix the variable by overwriting its bounds "
"in the MPS file." % (vardata.cname(True), model.cname(True)))
if vardata.value is None:
raise ValueError("Variable cannot be fixed to a value of None.")
output_file.write((" FX BOUND "+entry_template)
% (var_label, value(vardata.value)))
continue
vardata_lb = self._get_bound(vardata.lb)
vardata_ub = self._get_bound(vardata.ub)
# Make it harder for -0 to show up in
# the output. This makes file diffing
# for test baselines slightly less
# annoying
if vardata_lb == 0:
vardata_lb = 0
if vardata_ub == 0:
vardata_ub = 0
unbounded_lb = (vardata_lb is None) or (vardata_lb == -infinity)
unbounded_ub = (vardata_ub is None) or (vardata_ub == infinity)
treat_as_integer = False
if vardata.is_binary():
if (vardata_lb == 0) and (vardata_ub == 1):
output_file.write(" BV BOUND %s\n" % (var_label))
continue
else:
# so we can add bounds
treat_as_integer = True
if treat_as_integer or vardata.is_integer():
# Indicating unbounded integers is tricky because
# the only way to indicate a variable is integer
# is using the bounds section. Thus, we signify
# infinity with a large number (10E20)
# * Note: Gurobi allows values like inf and -inf
# but CPLEX 12.6 does not, so I am just
# using a large value
if not unbounded_lb:
output_file.write((" LI BOUND "+entry_template)
% (var_label, vardata_lb))
else:
output_file.write(" LI BOUND %s -10E20\n" % (var_label))
if not unbounded_ub:
output_file.write((" UI BOUND "+entry_template)
% (var_label, vardata_ub))
else:
output_file.write(" UI BOUND %s 10E20\n" % (var_label))
else:
assert vardata.is_continuous()
if unbounded_lb and unbounded_ub:
output_file.write(" FR BOUND %s\n" % (var_label))
else:
if not unbounded_lb:
output_file.write((" LO BOUND "+entry_template)
% (var_label, vardata_lb))
else:
output_file.write(" MI BOUND %s\n" % (var_label))
if not unbounded_ub:
output_file.write((" UP BOUND "+entry_template)
% (var_label, vardata_ub))
#
# SOS section
#
output_file.write(SOSlines.getvalue())
# Formatting of the next two sections comes from looking
# at Gurobi and Cplex output
#
# QUADOBJ section
#
if len(quadobj_data) > 0:
assert len(quadobj_data) == 1
# it looks like the COIN-OR MPS Reader only
# recognizes QUADOBJ (Gurobi and Cplex seem to
# be okay with this)
output_file.write("QUADOBJ\n")
#output_file.write("QMATRIX\n")
label, quad_terms = quadobj_data[0]
assert label == objective_label
for (var1, var2), coef in sorted(quad_terms,
key=lambda _x: (variable_to_column[_x[0][0]],
variable_to_column[_x[0][1]])):
var1_label = variable_symbol_dictionary[id(var1)]
var2_label = variable_symbol_dictionary[id(var2)]
# Don't forget that a quadratic objective is always
# assumed to be divided by 2
if var1_label == var2_label:
output_file.write(column_template % (var1_label,
var2_label,
coef * 2))
else:
# the matrix needs to be symmetric so split
# the coefficient (but remember it is divided by 2)
output_file.write(column_template % (var1_label,
var2_label,
coef))
output_file.write(column_template % (var2_label,
var1_label,
coef))
#
# QCMATRIX section
#
if len(quadmatrix_data) > 0:
for row_label, quad_terms in quadmatrix_data:
output_file.write("QCMATRIX %s\n" % (row_label))
for (var1, var2), coef in sorted(quad_terms,
key=lambda _x: (variable_to_column[_x[0][0]],
variable_to_column[_x[0][1]])):
var1_label = variable_symbol_dictionary[id(var1)]
var2_label = variable_symbol_dictionary[id(var2)]
if var1_label == var2_label:
output_file.write(column_template % (var1_label,
var2_label,
coef))
else:
# the matrix needs to be symmetric so split
# the coefficient
output_file.write(column_template % (var1_label,
var2_label,
coef * 0.5))
output_file.write(column_template % (var2_label,
var1_label,
coef * 0.5))
output_file.write("ENDATA\n")
# Clean up the symbol map to only contain variables referenced
# in the active constraints **Note**: warm start method may
# rely on this for choosing the set of potential warm start
# variables
vars_to_delete = set(variable_symbol_map.byObject.keys()) - \
set(self._referenced_variable_ids.keys())
sm_byObject = symbol_map.byObject
sm_bySymbol = symbol_map.bySymbol
var_sm_byObject = variable_symbol_map.byObject
for varid in vars_to_delete:
symbol = var_sm_byObject[varid]
del sm_byObject[varid]
del sm_bySymbol[symbol]
del variable_symbol_map
return symbol_map
def _xform_constraint(self, _name, constraint, varMap, disjunct, block):
lin_body_map = getattr(block,"lin_body",None)
for cname, c in iteritems(constraint._data):
name = _name + ('.%s' % (cname,) if cname else '')
if (not lin_body_map is None) and (not lin_body_map.get(c) is None):
raise GDP_Error('GDP(cHull) cannot process linear ' \
'constraint bodies (yet) (found at ' + name + ').')
constant = 0
try:
cannonical = generate_canonical_repn(c.body)
if isinstance(cannonical, LinearCanonicalRepn):
NL = False
else:
NL = canonical_is_nonlinear(cannonical)
except:
NL = True
# We need to evaluate teh expression at the origin *before*
# we substitute the expression variables with the
# disaggregated variables
if NL and self._mode == NL_Mode_FurmanSawayaGrossmann:
h_0 = value( self._eval_at_origin(
NL, c.body.clone(), disjunct.indicator_var, varMap ) )
expr = self._var_subst(NL, c.body, disjunct.indicator_var, varMap)
if NL:
y = disjunct.indicator_var
if self._mode == NL_Mode_LeeGrossmann:
expr = expr * y
elif self._mode == NL_Mode_GrossmannLee:
expr = (y + EPS) * expr
elif self._mode == NL_Mode_FurmanSawayaGrossmann:
expr = ((1-EPS)*y + EPS)*expr - EPS*h_0*(1-y)
else:
raise RuntimeError("Unknown NL CHull mode")
else:
# We need to make sure to pull out the constant terms
# from the expression and put them into the lb/ub
if cannonical.constant == None:
constant = 0
else:
constant = cannonical.constant
if c.lower is not None:
if __debug__ and logger.isEnabledFor(logging.DEBUG):
logger.debug("GDP(cHull): Promoting constraint " +
"'%s' as '%s_lo'", name, name)
bound = c.lower() - constant
if bound != 0:
newC = Constraint( expr = bound*disjunct.indicator_var \
<= expr - constant )
else:
newC = Constraint( expr = bound <= expr - constant )
block.add_component( name+"_lo", newC )
newC.construct()
if c.upper is not None:
if __debug__ and logger.isEnabledFor(logging.DEBUG):
logger.debug("GDP(cHull): Promoting constraint " +
"'%s' as '%s_hi'", name, name)
bound = c.upper() - constant
if bound != 0:
newC = Constraint( expr = expr - constant <= \
bound*disjunct.indicator_var )
else:
newC = Constraint( expr = expr - constant <= bound )
block.add_component( name+"_hi", newC )
newC.construct()
def compile_instance(self,
pyomo_instance,
symbolic_solver_labels=False,
output_fixed_variable_bounds=False,
skip_trivial_constraints=False):
from pyomo.core.base import Var, Constraint, SOSConstraint
from pyomo.repn import canonical_is_constant, LinearCanonicalRepn, canonical_degree
self._symbolic_solver_labels = symbolic_solver_labels
self._output_fixed_variable_bounds = output_fixed_variable_bounds
self._skip_trivial_constraints = skip_trivial_constraints
self._has_quadratic_constraints = False
self._has_quadratic_objective = False
used_sos_constraints = False
self._active_cplex_instance = cplex.Cplex()
if self._symbolic_solver_labels:
labeler = self._labeler = TextLabeler()
else:
labeler = self._labeler = NumericLabeler('x')
self._symbol_map = SymbolMap()
self._instance = pyomo_instance
pyomo_instance.solutions.add_symbol_map(self._symbol_map)
self._smap_id = id(self._symbol_map)
# we use this when iterating over the constraints because it
# will have a much smaller hash table, we also use this for
# the warm start code after it is cleaned to only contain
# variables referenced in the constraints
self._variable_symbol_map = SymbolMap()
# cplex wants the caller to set the problem type, which is (for
# current purposes) strictly based on variable type counts.
num_binary_variables = 0
num_integer_variables = 0
num_continuous_variables = 0
#############################################
# populate the variables in the cplex model #
#############################################
var_names = []
var_lbs = []
var_ubs = []
var_types = []
self._referenced_variable_ids.clear()
# maps pyomo var data labels to the corresponding CPLEX variable id.
self._cplex_variable_ids.clear()
# cached in the loop below - used to update the symbol map
# immediately following loop termination.
var_label_pairs = []
for var_data in pyomo_instance.component_data_objects(Var, active=True):
if var_data.fixed and not self._output_fixed_variable_bounds:
# if a variable is fixed, and we're preprocessing
# fixed variables (as in not outputting them), there
# is no need to add them to the compiled model.
continue
var_name = self._symbol_map.getSymbol(var_data, labeler)
var_names.append(var_name)
var_label_pairs.append((var_data, var_name))
self._cplex_variable_ids[var_name] = len(self._cplex_variable_ids)
if (var_data.lb is None) or (var_data.lb == -infinity):
var_lbs.append(-cplex.infinity)
else:
var_lbs.append(value(var_data.lb))
if (var_data.ub is None) or (var_data.ub == infinity):
var_ubs.append(cplex.infinity)
else:
var_ubs.append(value(var_data.ub))
if var_data.is_integer():
var_types.append(self._active_cplex_instance.variables.type.integer)
num_integer_variables += 1
elif var_data.is_binary():
var_types.append(self._active_cplex_instance.variables.type.binary)
num_binary_variables += 1
elif var_data.is_continuous():
var_types.append(self._active_cplex_instance.variables.type.continuous)
num_continuous_variables += 1
else:
raise TypeError("Invalid domain type for variable with name '%s'. "
"Variable is not continuous, integer, or binary.")
self._active_cplex_instance.variables.add(names=var_names,
lb=var_lbs,
ub=var_ubs,
types=var_types)
self._active_cplex_instance.variables.add(lb=[1],
ub=[1],
names=["ONE_VAR_CONSTANT"])
self._cplex_variable_ids["ONE_VAR_CONSTANT"] = len(self._cplex_variable_ids)
self._variable_symbol_map.addSymbols(var_label_pairs)
self._cplex_variable_names = self._active_cplex_instance.variables.get_names()
########################################################
# populate the standard constraints in the cplex model #
########################################################
expressions = []
senses = []
rhss = []
range_values = []
names = []
qexpressions = []
qlinears = []
qsenses = []
qrhss = []
qnames = []
for block in pyomo_instance.block_data_objects(active=True):
gen_con_canonical_repn = \
getattr(block, "_gen_con_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for con in block.component_data_objects(Constraint,
active=True,
descend_into=False):
if (con.lower is None) and \
(con.upper is None):
continue # not binding at all, don't bother
con_repn = None
if isinstance(con, LinearCanonicalRepn):
con_repn = con
else:
if gen_con_canonical_repn:
con_repn = generate_canonical_repn(con.body)
block_canonical_repn[con] = con_repn
else:
con_repn = block_canonical_repn[con]
# There are conditions, e.g., when fixing variables, under which
# a constraint block might be empty. Ignore these, for both
# practical reasons and the fact that the CPLEX LP format
# requires a variable in the constraint body. It is also
# possible that the body of the constraint consists of only a
# constant, in which case the "variable" of
if isinstance(con_repn, LinearCanonicalRepn):
if (con_repn.linear is None) and \
self._skip_trivial_constraints:
continue
else:
# we shouldn't come across a constant canonical repn
# that is not LinearCanonicalRepn
assert not canonical_is_constant(con_repn)
name = self._symbol_map.getSymbol(con, labeler)
expr = None
qexpr = None
quadratic = False
if isinstance(con_repn, LinearCanonicalRepn):
expr, offset = \
self._encode_constraint_body_linear_specialized(con_repn,
labeler,
use_variable_names=False,
cplex_variable_name_index_map=self._cplex_variable_ids)
else:
degree = canonical_degree(con_repn)
if degree == 2:
quadratic = True
elif (degree != 0) or (degree != 1):
raise ValueError(
"CPLEXPersistent plugin does not support general nonlinear "
"constraint expression (only linear or quadratic).\n"
"Constraint: %s" % (con.cname(True)))
expr, offset = self._encode_constraint_body_linear(con_repn,
labeler)
if quadratic:
if expr is None:
expr = cplex.SparsePair(ind=[0],val=[0.0])
self._has_quadratic_constraints = True
qexpr = self._encode_constraint_body_quadratic(con_repn,labeler)
qnames.append(name)
if con.equality:
# equality constraint.
qsenses.append('E')
qrhss.append(self._get_bound(con.lower) - offset)
elif (con.lower is not None) and (con.upper is not None):
raise RuntimeError(
"The CPLEXDirect plugin can not translate range "
"constraints containing quadratic expressions.")
elif con.lower is not None:
assert con.upper is None
qsenses.append('G')
qrhss.append(self._get_bound(con.lower) - offset)
else:
qsenses.append('L')
qrhss.append(self._get_bound(con.upper) - offset)
qlinears.append(expr)
qexpressions.append(qexpr)
else:
names.append(name)
expressions.append(expr)
if con.equality:
# equality constraint.
senses.append('E')
rhss.append(self._get_bound(con.lower) - offset)
range_values.append(0.0)
elif (con.lower is not None) and (con.upper is not None):
# ranged constraint.
senses.append('R')
lower_bound = self._get_bound(con.lower) - offset
upper_bound = self._get_bound(con.upper) - offset
rhss.append(lower_bound)
range_values.append(upper_bound - lower_bound)
elif con.lower is not None:
senses.append('G')
rhss.append(self._get_bound(con.lower) - offset)
range_values.append(0.0)
else:
senses.append('L')
rhss.append(self._get_bound(con.upper) - offset)
range_values.append(0.0)
###################################################
# populate the SOS constraints in the cplex model #
###################################################
# SOS constraints - largely taken from cpxlp.py so updates there,
# should be applied here
# TODO: Allow users to specify the variables coefficients for custom
# branching/set orders - refer to cpxlp.py
sosn = self._capabilities.sosn
sos1 = self._capabilities.sos1
sos2 = self._capabilities.sos2
modelSOS = ModelSOS()
for soscondata in pyomo_instance.component_data_objects(SOSConstraint,
active=True):
level = soscondata.level
if (level == 1 and not sos1) or \
(level == 2 and not sos2) or \
(level > 2 and not sosn):
raise Exception("Solver does not support SOS level %s constraints"
% (level,))
modelSOS.count_constraint(self._symbol_map,
labeler,
self._variable_symbol_map,
soscondata)
if modelSOS.sosType:
for key in modelSOS.sosType:
self._active_cplex_instance.SOS.add(type = modelSOS.sosType[key],
name = modelSOS.sosName[key],
SOS = [modelSOS.varnames[key],
modelSOS.weights[key]])
self._referenced_variable_ids.update(modelSOS.varids[key])
used_sos_constraints = True
self._active_cplex_instance.linear_constraints.add(
lin_expr=expressions,
senses=senses,
rhs=rhss,
range_values=range_values,
names=names)
for index in xrange(len(qexpressions)):
self._active_cplex_instance.quadratic_constraints.add(
lin_expr=qlinears[index],
quad_expr=qexpressions[index],
sense=qsenses[index],
rhs=qrhss[index],
name=qnames[index])
#############################################
# populate the objective in the cplex model #
#############################################
self.compile_objective(pyomo_instance)
################################################
# populate the problem type in the cplex model #
################################################
# This gets rid of the annoying "Freeing MIP data." message.
def _filter_freeing_mip_data(val):
if val.strip() == 'Freeing MIP data.':
return ""
return val
self._active_cplex_instance.set_warning_stream(sys.stderr,
fn=_filter_freeing_mip_data)
if (self._has_quadratic_objective is True) or \
(self._has_quadratic_constraints is True):
if (num_integer_variables > 0) or \
(num_binary_variables > 0) or \
(used_sos_constraints):
if self._has_quadratic_constraints is True:
self._active_cplex_instance.set_problem_type(
self._active_cplex_instance.problem_type.MIQCP)
else:
self._active_cplex_instance.set_problem_type(
self._active_cplex_instance.problem_type.MIQP)
else:
if self._has_quadratic_constraints is True:
self._active_cplex_instance.set_problem_type(
self._active_cplex_instance.problem_type.QCP)
else:
self._active_cplex_instance.set_problem_type(
self._active_cplex_instance.problem_type.QP)
elif (num_integer_variables > 0) or \
(num_binary_variables > 0) or \
(used_sos_constraints):
self._active_cplex_instance.set_problem_type(
self._active_cplex_instance.problem_type.MILP)
else:
self._active_cplex_instance.set_problem_type(
self._active_cplex_instance.problem_type.LP)
# restore the warning stream without our filter function
self._active_cplex_instance.set_warning_stream(sys.stderr)
def compile_instance(self,
pyomo_instance,
symbolic_solver_labels=False,
output_fixed_variable_bounds=False,
skip_trivial_constraints=False):
from pyomo.core.base import Var, Constraint, SOSConstraint
from pyomo.repn import canonical_is_constant, LinearCanonicalRepn, canonical_degree
self._symbolic_solver_labels = symbolic_solver_labels
self._output_fixed_variable_bounds = output_fixed_variable_bounds
self._skip_trivial_constraints = skip_trivial_constraints
self._has_quadratic_constraints = False
self._has_quadratic_objective = False
self._active_cplex_instance = CPLEXDirect._cplex_module.Cplex()
if self._symbolic_solver_labels:
labeler = self._labeler = TextLabeler()
else:
labeler = self._labeler = NumericLabeler('x')
self._symbol_map = SymbolMap()
self._instance = pyomo_instance
if isinstance(pyomo_instance, IBlockStorage):
# BIG HACK
if not hasattr(pyomo_instance, "._symbol_maps"):
setattr(pyomo_instance, "._symbol_maps", {})
getattr(pyomo_instance, "._symbol_maps")[id(self._symbol_map)] = \
self._symbol_map
else:
pyomo_instance.solutions.add_symbol_map(self._symbol_map)
self._smap_id = id(self._symbol_map)
# we use this when iterating over the constraints because it
# will have a much smaller hash table, we also use this for
# the warm start code after it is cleaned to only contain
# variables referenced in the constraints
self._variable_symbol_map = SymbolMap()
# cplex wants the caller to set the problem type, which is (for
# current purposes) strictly based on variable type counts.
self._num_binary_variables = 0
self._num_integer_variables = 0
self._num_continuous_variables = 0
self._used_sos_constraints = False
#############################################
# populate the variables in the cplex model #
#############################################
var_names = []
var_lbs = []
var_ubs = []
var_types = []
self._referenced_variable_ids.clear()
# maps pyomo var data labels to the corresponding CPLEX variable id.
self._cplex_variable_ids.clear()
# cached in the loop below - used to update the symbol map
# immediately following loop termination.
var_label_pairs = []
for var_data in pyomo_instance.component_data_objects(Var, active=True):
if var_data.fixed and not self._output_fixed_variable_bounds:
# if a variable is fixed, and we're preprocessing
# fixed variables (as in not outputting them), there
# is no need to add them to the compiled model.
continue
var_name = self._symbol_map.getSymbol(var_data, labeler)
var_names.append(var_name)
var_label_pairs.append((var_data, var_name))
self._cplex_variable_ids[var_name] = len(self._cplex_variable_ids)
if not var_data.has_lb():
var_lbs.append(-CPLEXDirect._cplex_module.infinity)
else:
var_lbs.append(value(var_data.lb))
if not var_data.has_ub():
var_ubs.append(CPLEXDirect._cplex_module.infinity)
else:
var_ubs.append(value(var_data.ub))
if var_data.is_integer():
var_types.append(self._active_cplex_instance.variables.type.integer)
self._num_integer_variables += 1
elif var_data.is_binary():
var_types.append(self._active_cplex_instance.variables.type.binary)
self._num_binary_variables += 1
elif var_data.is_continuous():
var_types.append(self._active_cplex_instance.variables.type.continuous)
self._num_continuous_variables += 1
else:
raise TypeError("Invalid domain type for variable with name '%s'. "
"Variable is not continuous, integer, or binary.")
self._active_cplex_instance.variables.add(names=var_names,
lb=var_lbs,
ub=var_ubs,
types=var_types)
self._active_cplex_instance.variables.add(lb=[1],
ub=[1],
names=["ONE_VAR_CONSTANT"])
self._cplex_variable_ids["ONE_VAR_CONSTANT"] = len(self._cplex_variable_ids)
self._variable_symbol_map.addSymbols(var_label_pairs)
self._cplex_variable_names = self._active_cplex_instance.variables.get_names()
########################################################
# populate the standard constraints in the cplex model #
########################################################
expressions = []
senses = []
rhss = []
range_values = []
names = []
qexpressions = []
qlinears = []
qsenses = []
qrhss = []
qnames = []
for block in pyomo_instance.block_data_objects(active=True):
gen_con_canonical_repn = \
getattr(block, "_gen_con_canonical_repn", True)
# Get/Create the ComponentMap for the repn
if not hasattr(block,'_canonical_repn'):
block._canonical_repn = ComponentMap()
block_canonical_repn = block._canonical_repn
for con in block.component_data_objects(Constraint,
active=True,
descend_into=False):
if (not con.has_lb()) and \
(not con.has_ub()):
assert not con.equality
continue # not binding at all, don't bother
con_repn = None
if con._linear_canonical_form:
con_repn = con.canonical_form()
elif isinstance(con, LinearCanonicalRepn):
con_repn = con
else:
if gen_con_canonical_repn:
con_repn = generate_canonical_repn(con.body)
block_canonical_repn[con] = con_repn
else:
con_repn = block_canonical_repn[con]
# There are conditions, e.g., when fixing variables, under which
# a constraint block might be empty. Ignore these, for both
# practical reasons and the fact that the CPLEX LP format
# requires a variable in the constraint body. It is also
# possible that the body of the constraint consists of only a
# constant, in which case the "variable" of
if isinstance(con_repn, LinearCanonicalRepn):
if self._skip_trivial_constraints and \
((con_repn.linear is None) or \
(len(con_repn.linear) == 0)):
continue
else:
# we shouldn't come across a constant canonical repn
# that is not LinearCanonicalRepn
assert not canonical_is_constant(con_repn)
name = self._symbol_map.getSymbol(con, labeler)
expr = None
qexpr = None
quadratic = False
if isinstance(con_repn, LinearCanonicalRepn):
expr, offset = \
self._encode_constraint_body_linear_specialized(con_repn,
labeler,
use_variable_names=False,
cplex_variable_name_index_map=self._cplex_variable_ids)
else:
degree = canonical_degree(con_repn)
if degree == 2:
quadratic = True
elif (degree != 0) or (degree != 1):
raise ValueError(
"CPLEXPersistent plugin does not support general nonlinear "
"constraint expression (only linear or quadratic).\n"
"Constraint: %s" % (con.name))
expr, offset = self._encode_constraint_body_linear(con_repn,
labeler)
if quadratic:
if expr is None:
expr = CPLEXDirect._cplex_module.SparsePair(ind=[0],val=[0.0])
self._has_quadratic_constraints = True
qexpr = self._encode_constraint_body_quadratic(con_repn,labeler)
qnames.append(name)
if con.equality:
# equality constraint.
qsenses.append('E')
qrhss.append(self._get_bound(con.lower) - offset)
elif con.has_lb() and con.has_ub():
raise RuntimeError(
"The CPLEXDirect plugin can not translate range "
"constraints containing quadratic expressions.")
elif con.has_lb():
assert not con.has_ub()
qsenses.append('G')
qrhss.append(self._get_bound(con.lower) - offset)
else:
assert con.has_ub()
qsenses.append('L')
qrhss.append(self._get_bound(con.upper) - offset)
qlinears.append(expr)
qexpressions.append(qexpr)
else:
names.append(name)
expressions.append(expr)
if con.equality:
# equality constraint.
senses.append('E')
rhss.append(self._get_bound(con.lower) - offset)
range_values.append(0.0)
elif con.has_lb() and con.has_ub():
# ranged constraint.
senses.append('R')
lower_bound = self._get_bound(con.lower) - offset
upper_bound = self._get_bound(con.upper) - offset
rhss.append(lower_bound)
range_values.append(upper_bound - lower_bound)
elif con.has_lb():
senses.append('G')
rhss.append(self._get_bound(con.lower) - offset)
range_values.append(0.0)
else:
assert con.has_ub()
senses.append('L')
rhss.append(self._get_bound(con.upper) - offset)
range_values.append(0.0)
###################################################
# populate the SOS constraints in the cplex model #
###################################################
# SOS constraints - largely taken from cpxlp.py so updates there,
# should be applied here
# TODO: Allow users to specify the variables coefficients for custom
# branching/set orders - refer to cpxlp.py
sosn = self._capabilities.sosn
sos1 = self._capabilities.sos1
sos2 = self._capabilities.sos2
modelSOS = ModelSOS()
for soscondata in pyomo_instance.component_data_objects(SOSConstraint,
active=True):
level = soscondata.level
if (level == 1 and not sos1) or \
(level == 2 and not sos2) or \
(level > 2 and not sosn):
raise Exception("Solver does not support SOS level %s constraints"
% (level,))
modelSOS.count_constraint(self._symbol_map,
labeler,
self._variable_symbol_map,
soscondata)
if modelSOS.sosType:
for key in modelSOS.sosType:
self._active_cplex_instance.SOS.add(type = modelSOS.sosType[key],
name = modelSOS.sosName[key],
SOS = [modelSOS.varnames[key],
modelSOS.weights[key]])
self._referenced_variable_ids.update(modelSOS.varids[key])
self._used_sos_constraints = True
self._active_cplex_instance.linear_constraints.add(
lin_expr=expressions,
senses=senses,
rhs=rhss,
range_values=range_values,
names=names)
for index in xrange(len(qexpressions)):
self._active_cplex_instance.quadratic_constraints.add(
lin_expr=qlinears[index],
quad_expr=qexpressions[index],
sense=qsenses[index],
rhs=qrhss[index],
name=qnames[index])
#############################################
# populate the objective in the cplex model #
#############################################
self.compile_objective(pyomo_instance)
def to_standard_form(self):
"""
Produces a standard-form representation of the model. Returns
the coefficient matrix (A), the cost vector (c), and the
constraint vector (b), where the 'standard form' problem is
min/max c'x
s.t. Ax = b
x >= 0
All three returned values are instances of the array.array
class, and store Python floats (C doubles).
"""
from pyomo.repn import generate_canonical_repn
# We first need to create an map of all variables to their column
# number
colID = {}
ID2name = {}
id = 0
tmp = self.variables().keys()
tmp.sort()
for v in tmp:
colID[v] = id
ID2name[id] = v
id += 1
# First we go through the constraints and introduce slack and excess
# variables to eliminate inequality constraints
#
# N.B. Structure heirarchy:
#
# active_components: {class: {attr_name: object}}
# object -> Constraint: ._data: {ndx: _ConstraintData}
# _ConstraintData: .lower, .body, .upper
#
# So, altogether, we access a lower bound via
#
# model.component_map(active=True)[Constraint]['con_name']['index'].lower
#
# {le,ge,eq}Constraints are
# {constraint_name: {index: {variable_or_none: coefficient}} objects
# that represent each constraint. None in the innermost dictionary
# represents the constant term.
#
# i.e.
#
# min x1 + 2*x2 + x4
# s.t. x1 = 1
# x2 + 3*x3 <= -1
# x1 + x4 >= 3
# x1 + 2*x2 + + 3*x4 >= 0
#
#
# would be represented as (modulo the names of the variables,
# constraints, and indices)
#
# eqConstraints = {'c1': {None: {'x1':1, None:-1}}}
# leConstraints = {'c2': {None: {'x2':1, 'x3':3, None:1}}}
# geConstraints = {'c3': {None: {'x1':1, 'x4':1, None:-3}},
# 'c4': {None: {'x1':1, 'x2':2, 'x4':1, None:0}}}
#
# Note the we have the luxury of dealing only with linear terms.
var_id_map = {}
leConstraints = {}
geConstraints = {}
eqConstraints = {}
objectives = {}
# For each registered component
for c in self.component_map(active=True):
# Get all subclasses of Constraint
if issubclass(c, Constraint):
cons = self.component_map(c, active=True)
# Get the name of the constraint, and the constraint set itself
for con_set_name in cons:
con_set = cons[con_set_name]
# For each indexed constraint in the constraint set
for ndx in con_set._data:
con = con_set._data[ndx]
# Process the body
terms = self._process_canonical_repn(
generate_canonical_repn(con.body, var_id_map))
# Process the bounds of the constraint
if con.equality:
# Equality constraint, only check lower bound
lb = self._process_canonical_repn(
generate_canonical_repn(con.lower, var_id_map))
# Update terms
for k in lb:
v = lb[k]
if k in terms:
terms[k] -= v
else:
terms[k] = -v
# Add constraint to equality constraints
eqConstraints[(con_set_name, ndx)] = terms
else:
# Process upper bounds (<= constraints)
if con.upper is not None:
# Less than or equal to constraint
tmp = dict(terms)
ub = self._process_canonical_repn(
generate_canonical_repn(con.upper, var_id_map))
# Update terms
for k in ub:
if k in terms:
tmp[k] -= ub[k]
else:
tmp[k] = -ub[k]
# Add constraint to less than or equal to
# constraints
leConstraints[(con_set_name, ndx)] = tmp
# Process lower bounds (>= constraints)
if con.lower is not None:
# Less than or equal to constraint
tmp = dict(terms)
lb = self._process_canonical_repn(
generate_canonical_repn(con.lower, var_id_map))
# Update terms
for k in lb:
if k in terms:
tmp[k] -= lb[k]
else:
tmp[k] = -lb[k]
# Add constraint to less than or equal to
# constraints
geConstraints[(con_set_name, ndx)] = tmp
elif issubclass(c, Objective):
# Process objectives
objs = self.component_map(c, active=True)
# Get the name of the objective, and the objective set itself
for obj_set_name in objs:
obj_set = objs[obj_set_name]
# For each indexed objective in the objective set
for ndx in obj_set._data:
obj = obj_set._data[ndx]
# Process the objective
terms = self._process_canonical_repn(
generate_canonical_repn(obj.expr, var_id_map))
objectives[(obj_set_name, ndx)] = terms
# We now have all the constraints. Add a slack variable for every
# <= constraint and an excess variable for every >= constraint.
nSlack = len(leConstraints)
nExcess = len(geConstraints)
nConstraints = len(leConstraints) + len(geConstraints) + \
len(eqConstraints)
nVariables = len(colID) + nSlack + nExcess
nRegVariables = len(colID)
# Make the arrays
coefficients = array.array("d", [0]*nConstraints*nVariables)
constraints = array.array("d", [0]*nConstraints)
costs = array.array("d", [0]*nVariables)
# Populate the coefficient matrix
constraintID = 0
# Add less than or equal to constraints
for ndx in leConstraints:
con = leConstraints[ndx]
for termKey in con:
coef = con[termKey]
if termKey is None:
# Constraint coefficient
constraints[constraintID] = -coef
else:
# Variable coefficient
col = colID[termKey]
coefficients[constraintID*nVariables + col] = coef
# Add the slack
coefficients[constraintID*nVariables + nRegVariables + \
constraintID] = 1
constraintID += 1
# Add greater than or equal to constraints
for ndx in geConstraints:
con = geConstraints[ndx]
for termKey in con:
coef = con[termKey]
if termKey is None:
# Constraint coefficient
constraints[constraintID] = -coef
else:
# Variable coefficient
col = colID[termKey]
coefficients[constraintID*nVariables + col] = coef
# Add the slack
coefficients[constraintID*nVariables + nRegVariables + \
constraintID] = -1
constraintID += 1
# Add equality constraints
for ndx in eqConstraints:
con = eqConstraints[ndx]
for termKey in con:
coef = con[termKey]
if termKey is None:
# Constraint coefficient
constraints[constraintID] = -coef
else:
# Variable coefficient
col = colID[termKey]
coefficients[constraintID*nVariables + col] = coef
constraintID += 1
# Determine cost coefficients
for obj_name in objectives:
obj = objectives[obj_name]()
for var in obj:
costs[colID[var]] = obj[var]
# Print the model
#
# The goal is to print
#
# var1 var2 var3 ...
# +-- --+
# | cost1 cost2 cost3 ...|
# +-- --+
# +-- --+ +-- --+
# con1 | coef11 coef12 coef13 ...| | eq1 |
# con2 | coef21 coef22 coef23 ...| | eq2 |
# con2 | coef31 coef32 coef33 ...| | eq3 |
# . | . . . . | | . |
# . | . . . . | | . |
# . | . . . . | | . |
constraintPadding = 2
numFmt = "% 1.4f"
altFmt = "% 1.1g"
maxColWidth = max(len(numFmt % 0.0), len(altFmt % 0.0))
maxConstraintColWidth = max(len(numFmt % 0.0), len(altFmt % 0.0))
# Generate constraint names
maxConNameLen = 0
conNames = []
for name in leConstraints:
strName = str(name)
if len(strName) > maxConNameLen:
maxConNameLen = len(strName)
conNames.append(strName)
for name in geConstraints:
strName = str(name)
if len(strName) > maxConNameLen:
maxConNameLen = len(strName)
conNames.append(strName)
for name in eqConstraints:
strName = str(name)
if len(strName) > maxConNameLen:
maxConNameLen = len(strName)
conNames.append(strName)
# Generate the variable names
varNames = [None]*len(colID)
for name in colID:
tmp_name = " " + name
if len(tmp_name) > maxColWidth:
maxColWidth = len(tmp_name)
varNames[colID[name]] = tmp_name
for i in xrange(0, nSlack):
tmp_name = " _slack_%i" % i
if len(tmp_name) > maxColWidth:
maxColWidth = len(tmp_name)
varNames.append(tmp_name)
for i in xrange(0, nExcess):
tmp_name = " _excess_%i" % i
if len(tmp_name) > maxColWidth:
maxColWidth = len(tmp_name)
varNames.append(tmp_name)
# Variable names
line = " "*maxConNameLen + (" "*constraintPadding) + " "
for col in xrange(0, nVariables):
# Format entry
token = varNames[col]
# Pad with trailing whitespace
token += " "*(maxColWidth - len(token))
# Add to line
line += " " + token + " "
print(line+'\n')
# Cost vector
print(" "*maxConNameLen + (" "*constraintPadding) + "+--" + \
" "*((maxColWidth+2)*nVariables - 4) + "--+" + '\n')
line = " "*maxConNameLen + (" "*constraintPadding) + "|"
for col in xrange(0, nVariables):
# Format entry
token = numFmt % costs[col]
if len(token) > maxColWidth:
token = altFmt % costs[col]
# Pad with trailing whitespace
token += " "*(maxColWidth - len(token))
# Add to line
line += " " + token + " "
line += "|"
print(line+'\n')
print(" "*maxConNameLen + (" "*constraintPadding) + "+--" + \
" "*((maxColWidth+2)*nVariables - 4) + "--+"+'\n')
# Constraints
print(" "*maxConNameLen + (" "*constraintPadding) + "+--" + \
" "*((maxColWidth+2)*nVariables - 4) + "--+" + \
(" "*constraintPadding) + "+--" + \
(" "*(maxConstraintColWidth-1)) + "--+"+'\n')
for row in xrange(0, nConstraints):
# Print constraint name
line = conNames[row] + (" "*constraintPadding) + (" "*(maxConNameLen - len(conNames[row]))) + "|"
# Print each coefficient
for col in xrange(0, nVariables):
# Format entry
token = numFmt % coefficients[nVariables*row + col]
if len(token) > maxColWidth:
token = altFmt % coefficients[nVariables*row + col]
# Pad with trailing whitespace
token += " "*(maxColWidth - len(token))
# Add to line
line += " " + token + " "
line += "|" + (" "*constraintPadding) + "|"
# Add constraint vector
token = numFmt % constraints[row]
if len(token) > maxConstraintColWidth:
token = altFmt % constraints[row]
# Pad with trailing whitespace
token += " "*(maxConstraintColWidth - len(token))
line += " " + token + " |"
print(line+'\n')
print(" "*maxConNameLen + (" "*constraintPadding) + "+--" + \
" "*((maxColWidth+2)*nVariables - 4) + "--+" + \
(" "*constraintPadding) + "+--" + (" "*(maxConstraintColWidth-1))\
+ "--+"+'\n')
return (coefficients, costs, constraints)
def collect_linear_terms(block, unfixed):
#
# Variables are constraints of block
# Constraints are unfixed variables of block and the parent model.
#
vnames = set()
for (name, data) in block.component_map(Constraint, active=True).items():
vnames.add((name, data.is_indexed()))
cnames = set(unfixed)
for (name, data) in block.component_map(Var, active=True).items():
cnames.add((name, data.is_indexed()))
#
A = {}
b_coef = {}
c_rhs = {}
c_sense = {}
d_sense = None
v_domain = {}
#
# Collect objective
#
for (oname, odata) in block.component_map(Objective, active=True).items():
for ndx in odata:
if odata[ndx].sense == maximize:
o_terms = generate_canonical_repn(-1 * odata[ndx].expr,
compute_values=False)
d_sense = minimize
else:
o_terms = generate_canonical_repn(odata[ndx].expr,
compute_values=False)
d_sense = maximize
for i in range(len(o_terms.variables)):
c_rhs[o_terms.variables[i].parent_component().name,
o_terms.variables[i].index()] = o_terms.linear[i]
# Stop after the first objective
break
#
# Collect constraints
#
for (name, data) in block.component_map(Constraint, active=True).items():
for ndx in data:
con = data[ndx]
body_terms = generate_canonical_repn(con.body,
compute_values=False)
lower_terms = generate_canonical_repn(
con.lower,
compute_values=False) if not con.lower is None else None
upper_terms = generate_canonical_repn(
con.upper,
compute_values=False) if not con.upper is None else None
#
if body_terms.constant is None:
body_terms.constant = 0
if not lower_terms is None and not lower_terms.variables is None:
raise (
RuntimeError,
"Error during dualization: Constraint '%s' has a lower bound that is non-constant"
)
if not upper_terms is None and not upper_terms.variables is None:
raise (
RuntimeError,
"Error during dualization: Constraint '%s' has an upper bound that is non-constant"
)
#
for i in range(len(body_terms.variables)):
varname = body_terms.variables[i].parent_component().name
varndx = body_terms.variables[i].index()
A.setdefault(body_terms.variables[i].parent_component().name,
{}).setdefault(varndx, []).append(
Bunch(coef=body_terms.linear[i],
var=name,
ndx=ndx))
#
if not con.equality:
#
# Inequality constraint
#
if lower_terms is None or lower_terms.constant is None:
#
# body <= upper
#
v_domain[name, ndx] = -1
b_coef[name,
ndx] = upper_terms.constant - body_terms.constant
elif upper_terms is None or upper_terms.constant is None:
#
# lower <= body
#
v_domain[name, ndx] = 1
b_coef[name,
ndx] = lower_terms.constant - body_terms.constant
else:
#
# lower <= body <= upper
#
# Dual for lower bound
#
ndx_ = tuple(list(ndx).append('lb'))
v_domain[name, ndx_] = 1
b_coef[name,
ndx] = lower_terms.constant - body_terms.constant
#
# Dual for upper bound
#
ndx_ = tuple(list(ndx).append('ub'))
v_domain[name, ndx_] = -1
b_coef[name,
ndx] = upper_terms.constant - body_terms.constant
else:
#
# Equality constraint
#
v_domain[name, ndx] = 0
b_coef[name, ndx] = lower_terms.constant - body_terms.constant
#
# Collect bound constraints
#
def all_vars(block):
"""
This conditionally chains together the active variables in the current block with
the active variables in all of the parent blocks (if any exist).
"""
while not block is None:
for (name, data) in block.component_map(Var, active=True).items():
yield (name, data)
block = block.parent_block()
for (name, data) in all_vars(block):
#
# Skip fixed variables (in the parent)
#
if not (name, data.is_indexed()) in cnames:
continue
#
# Iterate over all variable indices
#
for ndx in data:
var = data[ndx]
bounds = var.bounds
if bounds[0] is None and bounds[1] is None:
c_sense[name, ndx] = 'e'
elif bounds[0] is None:
if bounds[1] == 0.0:
c_sense[name, ndx] = 'g'
else:
c_sense[name, ndx] = 'e'
#
# Add constraint that defines the upper bound
#
name_ = name + "_upper_"
varname = data.parent_component().name
varndx = data[ndx].index()
A.setdefault(varname, {}).setdefault(varndx, []).append(
Bunch(coef=1.0, var=name_, ndx=ndx))
#
v_domain[name_, ndx] = -1
b_coef[name_, ndx] = bounds[1]
elif bounds[1] is None:
if bounds[0] == 0.0:
c_sense[name, ndx] = 'l'
else:
c_sense[name, ndx] = 'e'
#
# Add constraint that defines the lower bound
#
name_ = name + "_lower_"
varname = data.parent_component().name
varndx = data[ndx].index()
A.setdefault(varname, {}).setdefault(varndx, []).append(
Bunch(coef=1.0, var=name_, ndx=ndx))
#
v_domain[name_, ndx] = 1
b_coef[name_, ndx] = bounds[0]
else:
# Bounded above and below
c_sense[name, ndx] = 'e'
#
# Add constraint that defines the upper bound
#
name_ = name + "_upper_"
varname = data.parent_component().name
varndx = data[ndx].index()
A.setdefault(varname, {}).setdefault(varndx, []).append(
Bunch(coef=1.0, var=name_, ndx=ndx))
#
v_domain[name_, ndx] = -1
b_coef[name_, ndx] = bounds[1]
#
# Add constraint that defines the lower bound
#
name_ = name + "_lower_"
varname = data.parent_component().name
varndx = data[ndx].index()
A.setdefault(varname, {}).setdefault(varndx, []).append(
Bunch(coef=1.0, var=name_, ndx=ndx))
#
v_domain[name_, ndx] = 1
b_coef[name_, ndx] = bounds[0]
#
return (A, b_coef, c_rhs, c_sense, d_sense, vnames, cnames, v_domain)
def collect_linear_terms(block, unfixed):
#
# Variables are constraints of block
# Constraints are unfixed variables of block and the parent model.
#
vnames = set()
for (name, data) in block.component_map(Constraint, active=True).items():
vnames.add((name, data.is_indexed()))
cnames = set(unfixed)
for (name, data) in block.component_map(Var, active=True).items():
cnames.add((name, data.is_indexed()))
#
A = {}
b_coef = {}
c_rhs = {}
c_sense = {}
d_sense = None
v_domain = {}
#
# Collect objective
#
for (oname, odata) in block.component_map(Objective, active=True).items():
for ndx in odata:
if odata[ndx].sense == maximize:
o_terms = generate_canonical_repn(-1*odata[ndx].expr, compute_values=False)
d_sense = minimize
else:
o_terms = generate_canonical_repn(odata[ndx].expr, compute_values=False)
d_sense = maximize
for i in range(len(o_terms.variables)):
c_rhs[ o_terms.variables[i].parent_component().name, o_terms.variables[i].index() ] = o_terms.linear[i]
# Stop after the first objective
break
#
# Collect constraints
#
for (name, data) in block.component_map(Constraint, active=True).items():
for ndx in data:
con = data[ndx]
body_terms = generate_canonical_repn(con.body, compute_values=False)
lower_terms = generate_canonical_repn(con.lower, compute_values=False) if not con.lower is None else None
upper_terms = generate_canonical_repn(con.upper, compute_values=False) if not con.upper is None else None
#
if body_terms.constant is None:
body_terms.constant = 0
if not lower_terms is None and not lower_terms.variables is None:
raise(RuntimeError, "Error during dualization: Constraint '%s' has a lower bound that is non-constant")
if not upper_terms is None and not upper_terms.variables is None:
raise(RuntimeError, "Error during dualization: Constraint '%s' has an upper bound that is non-constant")
#
for i in range(len(body_terms.variables)):
varname = body_terms.variables[i].parent_component().name
varndx = body_terms.variables[i].index()
A.setdefault(body_terms.variables[i].parent_component().name, {}).setdefault(varndx,[]).append( Bunch(coef=body_terms.linear[i], var=name, ndx=ndx) )
#
if not con.equality:
#
# Inequality constraint
#
if lower_terms is None or lower_terms.constant is None:
#
# body <= upper
#
v_domain[name, ndx] = -1
b_coef[name,ndx] = upper_terms.constant - body_terms.constant
elif upper_terms is None or upper_terms.constant is None:
#
# lower <= body
#
v_domain[name, ndx] = 1
b_coef[name,ndx] = lower_terms.constant - body_terms.constant
else:
#
# lower <= body <= upper
#
# Dual for lower bound
#
ndx_ = tuple(list(ndx).append('lb'))
v_domain[name, ndx_] = 1
b_coef[name,ndx] = lower_terms.constant - body_terms.constant
#
# Dual for upper bound
#
ndx_ = tuple(list(ndx).append('ub'))
v_domain[name, ndx_] = -1
b_coef[name,ndx] = upper_terms.constant - body_terms.constant
else:
#
# Equality constraint
#
v_domain[name, ndx] = 0
b_coef[name,ndx] = lower_terms.constant - body_terms.constant
#
# Collect bound constraints
#
def all_vars(block):
"""
This conditionally chains together the active variables in the current block with
the active variables in all of the parent blocks (if any exist).
"""
while not block is None:
for (name, data) in block.component_map(Var, active=True).items():
yield (name, data)
block = block.parent_block()
for (name, data) in all_vars(block):
#
# Skip fixed variables (in the parent)
#
if not (name, data.is_indexed()) in cnames:
continue
#
# Iterate over all variable indices
#
for ndx in data:
var = data[ndx]
bounds = var.bounds
if bounds[0] is None and bounds[1] is None:
c_sense[name,ndx] = 'e'
elif bounds[0] is None:
if bounds[1] == 0.0:
c_sense[name,ndx] = 'g'
else:
c_sense[name,ndx] = 'e'
#
# Add constraint that defines the upper bound
#
name_ = name + "_upper_"
varname = data.parent_component().name
varndx = data[ndx].index()
A.setdefault(varname, {}).setdefault(varndx,[]).append( Bunch(coef=1.0, var=name_, ndx=ndx) )
#
v_domain[name_,ndx] = -1
b_coef[name_,ndx] = bounds[1]
elif bounds[1] is None:
if bounds[0] == 0.0:
c_sense[name,ndx] = 'l'
else:
c_sense[name,ndx] = 'e'
#
# Add constraint that defines the lower bound
#
name_ = name + "_lower_"
varname = data.parent_component().name
varndx = data[ndx].index()
A.setdefault(varname, {}).setdefault(varndx,[]).append( Bunch(coef=1.0, var=name_, ndx=ndx) )
#
v_domain[name_,ndx] = 1
b_coef[name_,ndx] = bounds[0]
else:
# Bounded above and below
c_sense[name,ndx] = 'e'
#
# Add constraint that defines the upper bound
#
name_ = name + "_upper_"
varname = data.parent_component().name
varndx = data[ndx].index()
A.setdefault(varname, {}).setdefault(varndx,[]).append( Bunch(coef=1.0, var=name_, ndx=ndx) )
#
v_domain[name_,ndx] = -1
b_coef[name_,ndx] = bounds[1]
#
# Add constraint that defines the lower bound
#
name_ = name + "_lower_"
varname = data.parent_component().name
varndx = data[ndx].index()
A.setdefault(varname, {}).setdefault(varndx,[]).append( Bunch(coef=1.0, var=name_, ndx=ndx) )
#
v_domain[name_,ndx] = 1
b_coef[name_,ndx] = bounds[0]
#
return (A, b_coef, c_rhs, c_sense, d_sense, vnames, cnames, v_domain)
