def build_Block_with_objects():
"""Build an empty Block"""
obj = Block(concrete=True)
obj.construct()
obj.x = Var()
obj.x._domain = None
obj.c = Constraint()
obj.o = Objective()
return obj
def build_Block_with_objects():
"""Build an empty Block"""
obj = Block(concrete=True)
obj.construct()
obj.x = Var()
obj.x._domain = None
obj.c = Constraint()
obj.o = Objective()
return obj
def get_numeric_incidence_matrix(variables, constraints):
"""
This function gets the numeric incidence matrix (Jacobian) of Pyomo
constraints with respect to variables.
"""
# NOTE: There are several ways to get a numeric incidence matrix
# from a Pyomo model. This function implements a somewhat roundabout
# method, which is to construct a dummy Block with the necessary
# variables and constraints, then construct a PyNumero PyomoNLP
# from the block and have PyNumero evaluate the desired Jacobian
# via ASL.
comps = list(variables) + list(constraints)
_check_unindexed(comps)
M, N = len(constraints), len(variables)
_block = Block()
_block.construct()
_block.obj = Objective(expr=0)
_block.vars = Reference(variables)
_block.cons = Reference(constraints)
var_set = ComponentSet(variables)
other_vars = []
for con in constraints:
for var in identify_variables(con.body, include_fixed=False):
# Fixed vars will be ignored by the nl file write, so
# there is no point to including them here.
# A different method of assembling this matrix, e.g.
# Pyomo's automatic differentiation, could support taking
# derivatives with respect to fixed variables.
if var not in var_set:
other_vars.append(var)
var_set.add(var)
# These variables are necessary due to the nl writer's philosophy
# about what constitutes a model. Note that we take derivatives with
# respect to them even though this is not necessary. We could fix them
# here to avoid doing this extra work, but that would alter the user's
# model, which we would rather not do.
_block.other_vars = Reference(other_vars)
_nlp = PyomoNLP(_block)
return _nlp.extract_submatrix_jacobian(variables, constraints)
def build_Block():
"""Build a Block with a few components."""
obj = Block(concrete=True)
obj.construct()
return obj
def build_Block():
"""Build a Block with a few components."""
obj = Block(concrete=True)
obj.construct()
return obj
