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Add BoneMarketModel.AddDivisionMultiplicationEquality

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This method combines two common operations, avoiding the need for
intermediate variables at the call site.
This commit is contained in:
Jeremy Saklad 2021-09-28 17:05:06 -05:00
parent 46edfcb35b
commit 1bf18fe8e1
Signed by: Jeremy Saklad
GPG Key ID: 9CA2149583EDBF84
1 changed files with 18 additions and 0 deletions
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18
bonemarketsolver/objects/bone_market_model.py
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@ -33,6 +33,24 @@ Each parameter is interpreted as a BoundedLinearExpression, and a layer of indir
super().AddDivisionEquality(intermediate_target, intermediate_num, intermediate_denom)
return (target_constraint, num_constraint, denom_constraint)
def AddDivisionMultiplicationEquality(self, target, num, denom, multiple = None):
"""Adds `target == (num // denom) * multiple`.
Each parameter is interpreted as a BoundedLinearExpression, and a layer of indirection is applied such that each Constraint in the returned tuple can accept an enforcement literal.
`multiple` defaults to the same value as `denom` if unspecified."""
quotient = self.NewIntVar(f'{repr(target)} == ({repr(num)} // {repr(denom)}) * {repr(multiple)}: quotient')
intermediate_num, num_constraint = self.NewIntermediateIntVar(num, f'{repr(target)} == ({repr(num)} // {repr(denom)}) * {repr(multiple)}: num', lb = 0)
intermediate_denom, denom_constraint = self.NewIntermediateIntVar(denom, f'{repr(target)} == ({repr(num)} // {repr(denom)}) * {repr(multiple)}: denom', lb = 0)
intermediate_target, target_constraint = self.NewIntermediateIntVar(target, f'{repr(target)} == ({repr(num)} // {repr(denom)}) * {repr(multiple)}: target')
if multiple:
intermediate_multiple, multiple_constraint = self.NewIntermediateIntVar(multiple, f'{repr(target)} == ({repr(num)} // {repr(denom)}) * {repr(multiple)}: multiple')
super().AddDivisionEquality(quotient, intermediate_num, intermediate_denom)
super().AddMultiplicationEquality(intermediate_target, (quotient, intermediate_multiple if multiple else intermediate_denom))
return (num_constraint, denom_constraint, target_constraint, *((multiple_constraint,) if multiple else ()))
def AddIf(self, variable, *constraints):
"""Add constraints to the model, only enforced if the specified variable is true.