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Change addConsNode to (also) accept ExprCons #418

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Merged
CGraczyk merged 4 commits into from
Mar 18, 2021
Merged

Change addConsNode to (also) accept ExprCons #418

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e049bc0
Prototype for addition of addExprConsNode to add ExprCons to Nodes.
CharJon Aug 24, 2020
9394b49
Extract _createLinCons
CharJon Aug 25, 2020
9684575
Unify createCons and make addConsNode more compact.
CharJon Aug 25, 2020
744b2bb
Fix segfault caused by addConsNode when called with ExprCons
CharJon Aug 25, 2020
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92 changes: 58 additions & 34 deletions src/pyscipopt/scip.pyx
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Original file line number Diff line number Diff line change
Expand Up @@ -1961,32 +1961,48 @@ cdef class Model:
"""
assert isinstance(cons, ExprCons), "given constraint is not ExprCons but %s" % cons.__class__.__name__

kwargs = self._cons_kwargs(check, cons, dynamic, enforce, initial, local, modifiable, name,
propagate, removable, separate,stickingatnode)
cdef Constraint py_cons
py_cons = self._createCons(cons, **kwargs)
cdef SCIP_CONS* scip_cons
scip_cons = <SCIP_CONS*> py_cons.scip_cons
PY_SCIP_CALL(SCIPaddCons(self._scip, scip_cons))
PY_SCIP_CALL(SCIPreleaseCons(self._scip, &scip_cons))
return py_cons

def _cons_kwargs(self, check, cons, dynamic, enforce, initial, local, modifiable, name, propagate, removable, separate,
stickingatnode):
# replace empty name with generic one
if name == '':
name = 'c'+str(SCIPgetNConss(self._scip)+1)

name = 'c' + str(SCIPgetNConss(self._scip) + 1)
kwargs = dict(name=name, initial=initial, separate=separate,
enforce=enforce, check=check,
propagate=propagate, local=local,
modifiable=modifiable, dynamic=dynamic,
removable=removable,
stickingatnode=stickingatnode)
kwargs['lhs'] = -SCIPinfinity(self._scip) if cons._lhs is None else cons._lhs
kwargs['rhs'] = SCIPinfinity(self._scip) if cons._rhs is None else cons._rhs
kwargs['rhs'] = SCIPinfinity(self._scip) if cons._rhs is None else cons._rhs
return kwargs

def _createCons(self, cons, **kwargs):
deg = cons.expr.degree()
cdef Constraint py_cons

if deg <= 1:
return self._addLinCons(cons, **kwargs)
py_cons = self._createLinCons(cons, **kwargs)
elif deg <= 2:
return self._addQuadCons(cons, **kwargs)
py_cons = self._createQuadCons(cons, **kwargs)
elif deg == float('inf'): # general nonlinear
return self._addGenNonlinearCons(cons, **kwargs)
return self._createGenNonlinearCons(cons, **kwargs)
else:
return self._addNonlinearCons(cons, **kwargs)
return self._createNonlinearCons(cons, **kwargs)
return py_cons

def _addLinCons(self, ExprCons lincons, **kwargs):
assert isinstance(lincons, ExprCons), "given constraint is not ExprCons but %s" % lincons.__class__.__name__

def _createLinCons(self, ExprCons lincons, **kwargs):
assert isinstance(lincons, ExprCons), "given constraint is not ExprCons but %s" % lincons.__class__.__name__
assert lincons.expr.degree() <= 1, "given constraint is not linear, degree == %d" % lincons.expr.degree()
terms = lincons.expr.terms

Expand All @@ -2007,17 +2023,12 @@ cdef class Model:
kwargs['separate'], kwargs['enforce'], kwargs['check'],
kwargs['propagate'], kwargs['local'], kwargs['modifiable'],
kwargs['dynamic'], kwargs['removable'], kwargs['stickingatnode']))

PY_SCIP_CALL(SCIPaddCons(self._scip, scip_cons))
PyCons = Constraint.create(scip_cons)
PY_SCIP_CALL(SCIPreleaseCons(self._scip, &scip_cons))

free(vars_array)
free(coeffs_array)

return PyCons
return Constraint.create(scip_cons)

def _addQuadCons(self, ExprCons quadcons, **kwargs):
def _createQuadCons(self, ExprCons quadcons, **kwargs):
terms = quadcons.expr.terms
assert quadcons.expr.degree() <= 2, "given constraint is not quadratic, degree == %d" % quadcons.expr.degree()

Expand All @@ -2040,12 +2051,9 @@ cdef class Model:
var1, var2 = <Variable>v[0], <Variable>v[1]
PY_SCIP_CALL(SCIPaddBilinTermQuadratic(self._scip, scip_cons, var1.scip_var, var2.scip_var, c))

PY_SCIP_CALL(SCIPaddCons(self._scip, scip_cons))
PyCons = Constraint.create(scip_cons)
PY_SCIP_CALL(SCIPreleaseCons(self._scip, &scip_cons))
return PyCons
return Constraint.create(scip_cons)

def _addNonlinearCons(self, ExprCons cons, **kwargs):
def _createNonlinearCons(self, ExprCons cons, **kwargs):
cdef SCIP_EXPR* expr
cdef SCIP_EXPR** varexprs
cdef SCIP_EXPRDATA_MONOMIAL** monomials
Expand Down Expand Up @@ -2098,16 +2106,13 @@ cdef class Model:
kwargs['check'], kwargs['propagate'], kwargs['local'],
kwargs['modifiable'], kwargs['dynamic'], kwargs['removable'],
kwargs['stickingatnode']) )
PY_SCIP_CALL(SCIPaddCons(self._scip, scip_cons))
PyCons = Constraint.create(scip_cons)
PY_SCIP_CALL(SCIPreleaseCons(self._scip, &scip_cons))
PY_SCIP_CALL( SCIPexprtreeFree(&exprtree) )
free(vars)
free(monomials)
free(varexprs)
return PyCons
return Constraint.create(scip_cons)

def _addGenNonlinearCons(self, ExprCons cons, **kwargs):
def _createGenNonlinearCons(self, ExprCons cons, **kwargs):
cdef SCIP_EXPR** childrenexpr
cdef SCIP_EXPR** scipexprs
cdef SCIP_EXPRTREE* exprtree
Expand Down Expand Up @@ -2191,16 +2196,14 @@ cdef class Model:
kwargs['check'], kwargs['propagate'], kwargs['local'],
kwargs['modifiable'], kwargs['dynamic'], kwargs['removable'],
kwargs['stickingatnode']) )
PY_SCIP_CALL(SCIPaddCons(self._scip, scip_cons))
PyCons = Constraint.create(scip_cons)
PY_SCIP_CALL(SCIPreleaseCons(self._scip, &scip_cons))
PY_SCIP_CALL( SCIPexprtreeFree(&exprtree) )

# free more memory
free(scipexprs)
free(vars)

return PyCons
return Constraint.create(scip_cons)

def addConsCoeff(self, Constraint cons, Variable var, coeff):
"""Add coefficient to the linear constraint (if non-zero).
Expand All @@ -2212,19 +2215,40 @@ cdef class Model:
"""
PY_SCIP_CALL(SCIPaddCoefLinear(self._scip, cons.scip_cons, var.scip_var, coeff))

def addConsNode(self, Node node, Constraint cons, Node validnode=None):
def addConsNode(self, Node node, cons, Node validnode=None, name="", initial=True, separate=True,
enforce=False, check=False, propagate=True, local=True,
modifiable=False, dynamic=False, removable=False, stickingatnode=True):
"""Add a constraint to the given node

:param Node node: node to add the constraint to
:param Constraint cons: constraint to add
:param Node validnode: more global node where cons is also valid

Note: Additional parameter for constraint settings get ignored if cons is not an ExprCons!
"""
cdef Constraint py_cons
cdef SCIP_CONS* scip_cons
if isinstance(cons, Constraint):
py_cons = <Constraint>cons
scip_cons = <SCIP_CONS*> py_cons.scip_cons
# TODO: (Why) Is this INCREF necessary?
Py_INCREF(cons)
elif isinstance(cons, ExprCons):
kwargs = self._cons_kwargs(check, cons, dynamic, enforce, initial, local, modifiable, name,
propagate, removable, separate,stickingatnode)
py_cons = self._createCons(cons, **kwargs)
scip_cons = <SCIP_CONS*> py_cons.scip_cons
else:
raise Warning(f"Argument cons is of incorrect type ({type(cons)}).")

if isinstance(validnode, Node):
PY_SCIP_CALL(SCIPaddConsNode(self._scip, node.scip_node, cons.scip_cons, validnode.scip_node))
PY_SCIP_CALL(SCIPaddConsNode(self._scip, node.scip_node, scip_cons, validnode.scip_node))
elif validnode is None:
PY_SCIP_CALL(SCIPaddConsNode(self._scip, node.scip_node, scip_cons, NULL))
else:
PY_SCIP_CALL(SCIPaddConsNode(self._scip, node.scip_node, cons.scip_cons, NULL))
Py_INCREF(cons)
raise Warning(f"Argument validnode is of incorrect type ({type(validnode)}).")
# TODO: This is needed for the ExprCons case. Is it a problem for the Constraint case?
PY_SCIP_CALL(SCIPreleaseCons(self._scip, &scip_cons))


def addConsLocal(self, Constraint cons, Node validnode=None):
"""Add a constraint to the current node
Expand Down