def add_edge(self, *args, **kwargs):
'''Adds an edge between `source` and `dest`. `shared_variables` represents a
list of variables, how `source` depends on `dest`. Returns edge object.
:param shared_variables: A list of variables.
:return: An :class:`Edge` instance.
'''
edge = None
if len(args) == 1:
edge = args[0]
if not isinstance(edge, Edge):
raise TypeError()
else:
edge = Edge(*args, **kwargs)
nx.DiGraph.add_edge(self, edge.get_source().get_name(),
edge.get_dest().get_name(),
edge)
logging.debug("Add edge between %s and %s with %d shared variable(s)",
edge.get_source().get_name(), edge.get_dest().get_name(),
edge.get_num_shared_variables())
for node in (self.node[edge.get_source().get_name()],
self.node[edge.get_dest().get_name()]):
node['shared_variables'] |= edge.get_shared_variables()
node['local_variables'] = (
set(node['model'].get_columns_names())
- set(node['shared_variables']))
return edge
def check_params(self, params):
if not isinstance(params, dict):
raise TypeError()
if params['num_blocks'] and max(params['num_constraints']) < max(params['num_blocks']):
logging.debug('Number of constraints cannot be less that number of blocks: %d < %d' \
% (max(params['num_constraints']), max(params['num_blocks'])))
return False
return True
def _process_decomposition_tree(self, tree):
# TODO(d2rk): merge nodes if necessary.
for node in tree.get_nodes():
if node.get_num_shared_variables() > self._driver_params.max_num_shared_variables:
logging.debug('Node %s has too many shared variables: %d > %d',
node.get_name(), node.get_num_shared_variables(),
self._driver_params.max_num_shared_variables)
return False
return True
def execute(self, sql, *args):
'''Replaces :func:`execute` with a logging variant.'''
if args:
parameters = []
for arg in args:
if isinstance(arg, buffer):
parameters.append('<blob>')
else:
parameters.append(repr(arg))
logging.debug('SQL Execute: %s - \n %s', sql,
'\n '.join(str(param) for param in parameters))
else:
logging.debug(sql)
return super(SQLiteCursorWrapper, self).execute(sql, *args)
def build_from_scratch(cls, objective_coefficients, constraints_coefficients,
constraints_senses, constraints_rhs,
constraints_names=[], variables_lower_bounds=[],
variables_upper_bounds=[], variables_names=[]):
"""Builds model from a scratch.
The following code snippet shows how to define two models from scratch,
where the first model needs to be maximized and the second one --
minimized::
MPModelBuilder.build_from_scratch([1, 1, 2], [[1, 2, 3], ['L', 'L'], [1, 1]])
MPModelBuilder.build_from_scratch(([1, 1, 2], False), [[1, 2, 3], ['L', 'L'], [1, 1]])
:param objective_coefficients: This parameter can be represented
either a list of objective function variable coefficients, or a tuple,
where the first element is a list of coefficients and the second one is
``True`` or ``False``, that defines objective function maximization or
minimization. By default does maximization (see :func:`set_objective`).
:param constraints_coefficients: Left-hand side or constraint matrix.
:param constraints_senses: A list of senses of the constraints.
:param constraints_rhs: A list of rhs bounds.
:param constraints_names: A list of constraints names.
:param variables_lower_bounds: A list of variables lower bounds.
:param variables_upper_bounds: A list of variables upper bounds.
:param variables_names: A list of variables names, where each name
represented by a string.
:returns: A :class:`MPModel` instance.
:raises: :exc:`TypeError`
"""
logging.debug('Build new model from scratch')
if not bool(len(variables_names)):
variables_names = []
for i in range(1, len(objective_coefficients) + 1):
variables_names.append(cls.VARIABLE_NAME_FORMAT.format(index=i))
if not bool(len(variables_lower_bounds)):
variables_lower_bounds = [0.0] * len(objective_coefficients)
if not bool(len(variables_upper_bounds)):
variables_upper_bounds = [1.0] * len(objective_coefficients)
if not bool(len(constraints_names)):
constraints_names = []
for i in range(1, len(constraints_senses) + 1):
constraints_names.append(cls.CONSTRAINT_NAME_FORMAT.format(index=i))
return (mp_model.MPModel()
.set_columns(variables_lower_bounds, variables_upper_bounds,
variables_names)
.set_objective(objective_coefficients)
.set_rows(constraints_coefficients, constraints_senses,
constraints_rhs, constraints_names))
def decompose(self):
self._decomposition_tree = decomposition_tree.DecompositionTree(self._model)
igraph = interaction_graph.InteractionGraph(self.get_model())
cliques = list(map(set, networkx.find_cliques(igraph)))
logging.debug("%d clique(s) were found." % len(cliques))
submodels_cache = []
for i, clique in enumerate(cliques):
submodel = self._build_submodel(clique)
self._decomposition_tree.add_node(submodel)
submodels_cache.append(submodel)
for j, other_clique in enumerate(cliques[:i]):
other_submodel = submodels_cache[j]
shared_cols_scope = clique & other_clique
if shared_cols_scope:
self._decomposition_tree.add_edge(submodel, other_submodel,
shared_cols_scope)
self._decomposition_tree.set_root(submodels_cache[-1])
def execute(self, request):
model = request.get_model()
logging.debug('Solve model %s that has %d row(s) and %d column(s)'
' with solver %s',
model.get_name(), model.get_num_rows(),
model.get_num_columns(), request.get_solver_id())
solver = backend_solvers.get_instance_of(request.get_solver_id())
if not solver:
raise Error("Cannot instantiate backend solver by id: %d" %
request.get_solver_id())
try:
solver.load_model(model)
solver.solve()
except Error, e:
# TODO: send back a report.
logging.exception("Cannot execute given request: cannot solve the model.")
return None
def set_root(self, root):
logging.debug("Set %s as root node." % root.get_name())
self._root = root
def _remove_node(self, node):
logging.debug('Remove node %s', node.get_name())
nodes = self._dtree_traversal.mark_node_as_visited(node)
for node in nodes:
self._add_node(node)
def _add_node(self, node):
logging.debug('Add node %s', node.get_name())
enumerator = shared_variables_enumerator.SharedVariablesEnumerator(
node.get_model(), node.get_shared_variables(), node.get_local_variables())
self._enumerators[node] = enumerator
self._unsolved_models_counter[node] = 0
def process_response(self, response):
cxt = self._frozen_contexts.pop(response.get_id())
solution = response.get_solution()
logging.debug("Process %s solution produced by %d with status %d",
response.get_id(), cxt.solver_id_stack[0], solution.get_status())
cxt.solver_id_stack.pop(0)
# Check F3: whether optimal solution has been found.
if (not solution.get_status() is mp_solution.MPSolution.NOT_SOLVED
and not solution.get_variables_values() is None):
if ((sum(solution.get_variables_values().tolist()) % 1.0) == 0 and
solution.is_optimal()):
objective_value = solution.get_objective_value()
# Check F2: do we need to continue?
# NOTE: the best objective value will be checked inside of
# set_best_objective_value().
if cxt.set_best_objective_value(objective_value):
logging.debug('Model %s has a new best objective value: %f',
response.get_id(), objective_value)
cxt.partial_solution.update_variables_values(solution)
cxt.partial_solution.set_objective_value(objective_value)
logging.debug('Write %s solution to the table.', response.get_id())
self._solution_table.write_solution(cxt.submodel, cxt.partial_solution)
else:
logging.debug("Solution is rejected: not the best objective value"
": %f <= %f", objective_value, cxt.best_objective_value)
else:
logging.debug("Solution is rejected: "
"not optimal or fractional solution.")
else:
logging.debug("Solution is rejected: model wasn't solved.")
if len(cxt.solver_id_stack) == 0:
self._search_tree.mark_model_as_solved(cxt.candidate_model)
else:
self._active_contexts[cxt.candidate_model.get_name()] = cxt
def executescript(self, sql):
'''Replaces :func:`executescript` with a logging variant.'''
logging.debug('SQL ExecuteScript: %s', sql)
return super(SQLiteCursorWrapper, self).executescript(sql)
def executemany(self, sql, seq_parameters):
'''Replaces executemany() with a logging variant.'''
seq_params_list = list(seq_parameters)
logging.debug('SQL ExecuteMany: %s - \n %s', sql,
'\n '.join(str(param) for param in seq_params_list))
return super(SQLiteCursorWrapper, self).executemany(sql, seq_params_list)