Comparison (cpmpy.transformations.comparison)

Transforms non-equality comparisons into equality comparisons as needed.

Let <op> be one of == or !=, <, <=, >, >=. Numeric expressions in Flat Normal Form are of the kind:

  • NumExpr <op> IV

  • BoolVar == NumExpr <op> IV

  • BoolVar -> NumExpr <op> IV

  • NumExpr <op> IV -> BoolVar

The NumExpr can be a sum, wsum or global function with a non-bool return type.

This file implements:

  • only_numexpr_equality(): transforms NumExpr <op> IV (also reified) to (NumExpr == A) & (A <op> IV) if not supported

cpmpy.transformations.comparison.only_numexpr_equality(constraints, supported=frozenset({}), csemap=None)[source]

Transforms NumExpr <op> IV to (NumExpr == A) & (A <op> IV) if not supported. Also for the reified uses of NumExpr

Parameters:

supported – a (frozen)set of expression names that supports all comparisons in the solver