always-cautious/ortools-clone
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

improve model_builder python

Browse Source
This commit is contained in:
Laurent Perron
2024-04-02 16:15:48 +02:00
parent 9a1fd0f602
commit 4fb80bbf97
2 changed files with 47 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

60
ortools/linear_solver/python/model_builder.py
View File

@@ -252,7 +252,7 @@ class Variable(LinearExpr):
ub: Optional[NumberT],
is_integral: Optional[bool],
name: Optional[str],
):
) -> None:
"""See Model.new_var below."""
LinearExpr.__init__(self)
self.__helper: mbh.ModelBuilderHelper = helper
@@ -420,6 +420,10 @@ def _add_linear_constraint_to_helper(
It handles boolean values (which might arise in the construction of
BoundedLinearExpressions).
If bounded_expr is a Boolean value, the created constraint is different.
In that case, the constraint will be immutable and marked as under-specified.
It will be always feasible or infeasible whether the value is True or False.
Args:
bounded_expr: The bounded expression used to create the constraint.
helper: The helper to create the constraint.
@@ -432,7 +436,7 @@ def _add_linear_constraint_to_helper(
TypeError: If constraint is an invalid type.
"""
if isinstance(bounded_expr, bool):
c = LinearConstraint(helper, None, True)
c = LinearConstraint(helper, is_under_specified=True)
if name is not None:
helper.set_constraint_name(c.index, name)
if bounded_expr:
@@ -462,6 +466,12 @@ def _add_enforced_linear_constraint_to_helper(
It handles boolean values (which might arise in the construction of
BoundedLinearExpressions).
If bounded_expr is a Boolean value, the linear part of the constraint is
different.
In that case, the constraint will be immutable and marked as under-specified.
Its linear part will be always feasible or infeasible whether the value is
True or False.
Args:
bounded_expr: The bounded expression used to create the constraint.
helper: The helper to create the constraint.
@@ -478,7 +488,7 @@ def _add_enforced_linear_constraint_to_helper(
"""
if isinstance(bounded_expr, bool):
# TODO(user): create indicator variable assignment instead ?
c = EnforcedLinearConstraint(helper, None, True)
c = EnforcedLinearConstraint(helper, is_under_specified=True)
c.indicator_variable = var
c.indicator_value = value
if name is not None:
@@ -559,7 +569,7 @@ class BoundedLinearExpression(_BoundedLinearExpr):
model.Add(x + 2 * y -1 >= z)
"""
def __init__(self, expr: LinearExprT, lb: NumberT, ub: NumberT):
def __init__(self, expr: LinearExprT, lb: NumberT, ub: NumberT) -> None:
self.__expr: LinearExprT = expr
self.__lb: np.double = mbn.assert_is_a_number(lb)
self.__ub: np.double = mbn.assert_is_a_number(ub)
@@ -654,9 +664,18 @@ class LinearConstraint:
def __init__(
self,
helper: mbh.ModelBuilderHelper,
*,
index: Optional[IntegerT] = None,
is_under_specified: bool = False,
):
) -> None:
"""LinearConstraint constructor.
Args:
helper: The pybind11 ModelBuilderHelper.
index: If specified, recreates a wrapper to an existing linear constraint.
is_under_specified: indicates if the constraint was created by
model.add(bool).
"""
if index is None:
self.__index = helper.add_linear_constraint()
else:
@@ -680,6 +699,7 @@ class LinearConstraint:
@lower_bound.setter
def lower_bound(self, bound: NumberT) -> None:
self.assert_constraint_is_well_defined()
self.__helper.set_constraint_lower_bound(self.__index, bound)
@property
@@ -688,6 +708,7 @@ class LinearConstraint:
@upper_bound.setter
def upper_bound(self, bound: NumberT) -> None:
self.assert_constraint_is_well_defined()
self.__helper.set_constraint_upper_bound(self.__index, bound)
@property
@@ -758,9 +779,18 @@ class EnforcedLinearConstraint:
def __init__(
self,
helper: mbh.ModelBuilderHelper,
*,
index: Optional[IntegerT] = None,
is_under_specified: bool = False,
):
) -> None:
"""EnforcedLinearConstraint constructor.
Args:
helper: The pybind11 ModelBuilderHelper.
index: If specified, recreates a wrapper to an existing linear constraint.
is_under_specified: indicates if the constraint was created by
model.add(bool).
"""
if index is None:
self.__index = helper.add_enforced_linear_constraint()
else:
@@ -790,6 +820,7 @@ class EnforcedLinearConstraint:
@lower_bound.setter
def lower_bound(self, bound: NumberT) -> None:
self.assert_constraint_is_well_defined()
self.__helper.set_enforced_constraint_lower_bound(self.__index, bound)
@property
@@ -798,6 +829,7 @@ class EnforcedLinearConstraint:
@upper_bound.setter
def upper_bound(self, bound: NumberT) -> None:
self.assert_constraint_is_well_defined()
self.__helper.set_enforced_constraint_upper_bound(self.__index, bound)
@property
@@ -1338,16 +1370,16 @@ class Model:
Note that a special treatment is done when the argument does not contain any
variable, and thus evaluates to True or False.
model.add(True) will create a constraint 0 <= empty sum <= 0.
`model.add(True)` will create a constraint 0 <= empty sum <= 0.
The constraint will be marked as under specified, and cannot be modified
further.
thereafter.
model.add(False) will create a constraint inf <= empty sum <= -inf. The
`model.add(False)` will create a constraint inf <= empty sum <= -inf. The
constraint will be marked as under specified, and cannot be modified
further.
thereafter.
you can check the if a constraint is under specified by
checking LinearConstraint.is_under_specified.
you can check the if a constraint is under specified by reading the
`LinearConstraint.is_under_specified` property.
"""
if isinstance(ct, _BoundedLinearExpr):
return ct._add_linear_constraint(self.__helper, name)
@@ -1368,7 +1400,7 @@ class Model:
def linear_constraint_from_index(self, index: IntegerT) -> LinearConstraint:
"""Rebuilds a linear constraint object from the model and its index."""
return LinearConstraint(self.__helper, index)
return LinearConstraint(self.__helper, index=index)
# EnforcedLinear constraints.
@@ -1473,7 +1505,7 @@ class Model:
self, index: IntegerT
) -> EnforcedLinearConstraint:
"""Rebuilds an enforced linear constraint object from the model and its index."""
return EnforcedLinearConstraint(self.__helper, index)
return EnforcedLinearConstraint(self.__helper, index=index)
# Objective.
def minimize(self, linear_expr: LinearExprT) -> None:

2
ortools/linear_solver/python/model_builder_test.py
View File

@@ -430,7 +430,7 @@ class InternalHelperTest(absltest.TestCase):
def test_anonymous_constraints(self):
helper = mb.Model().helper
index = helper.add_linear_constraint()
constraint = mb.LinearConstraint(helper, index)
constraint = mb.LinearConstraint(helper, index=index)
self.assertEqual(constraint.name, f"linear_constraint#{index}")