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RelaxationComponent: max_iterations

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Alinson S. Xavier
2020-12-04 10:30:38 -06:00
parent 0b41c882ff
commit 3823931382
1 changed files with 12 additions and 1 deletions
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13
miplearn/components/relaxation.py
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@@ -42,10 +42,13 @@ class RelaxationComponent(Component):
this threshold equals a small positive number to compensate for numerical issues. this threshold equals a small positive number to compensate for numerical issues.
check_dropped : bool, optional check_dropped : bool, optional
If `check_dropped` is true, then, after the problem is solved, the component verifies that all dropped If `check_dropped` is true, then, after the problem is solved, the component verifies that all dropped
constraints are still satisfied and re-adds the ones that are not. constraints are still satisfied, re-adds the violated ones and resolves the problem. This loop continues until
either no violations are found, or a maximum number of iterations is reached.
violation_tolerance : float, optional violation_tolerance : float, optional
If `check_dropped` is true, a constraint is considered satisfied during the check if its violation is smaller If `check_dropped` is true, a constraint is considered satisfied during the check if its violation is smaller
than this tolerance. than this tolerance.
max_iterations : int
If `check_dropped` is true, set the maximum number of iterations in the lazy constraint loop.
""" """
def __init__(self, def __init__(self,
@@ -54,6 +57,7 @@ class RelaxationComponent(Component):
slack_tolerance=1e-5, slack_tolerance=1e-5,
check_dropped=False, check_dropped=False,
violation_tolerance=1e-5, violation_tolerance=1e-5,
max_iterations=3,
): ):
self.classifiers = {} self.classifiers = {}
self.classifier_prototype = classifier self.classifier_prototype = classifier
@@ -62,8 +66,12 @@ class RelaxationComponent(Component):
self.pool = [] self.pool = []
self.check_dropped = check_dropped self.check_dropped = check_dropped
self.violation_tolerance = violation_tolerance self.violation_tolerance = violation_tolerance
self.max_iterations = max_iterations
self.current_iteration = 0
def before_solve(self, solver, instance, _): def before_solve(self, solver, instance, _):
self.current_iteration = 0
logger.info("Relaxing integrality...") logger.info("Relaxing integrality...")
solver.internal_solver.relax() solver.internal_solver.relax()
@@ -177,6 +185,9 @@ class RelaxationComponent(Component):
def iteration_cb(self, solver, instance, model): def iteration_cb(self, solver, instance, model):
if not self.check_dropped: if not self.check_dropped:
return False return False
if self.current_iteration >= self.max_iterations:
return False
self.current_iteration += 1
logger.debug("Checking that dropped constraints are satisfied...") logger.debug("Checking that dropped constraints are satisfied...")
constraints_to_add = [] constraints_to_add = []
for c in self.pool: for c in self.pool: