operations_research::sat::CompiledReservoirConstraint Class Reference

Detailed Description

This can be used to encode reservoir or a cumulative constraints for LS. We have a set of event time, and we use for overall violation the sum of overload over time.

This version support an incremental computation when just a few events changes, which is roughly O(n) instead of O(n log n) which makes it significantly faster than recomputing and sorting the profile on each ViolationDelta().

Definition at line 698 of file constraint_violation.h.

#include <constraint_violation.h>

Inheritance diagram for operations_research::sat::CompiledReservoirConstraint:

Public Member Functions
	CompiledReservoirConstraint (LinearExpressionProto capacity, std::vector< std::optional< int > > is_active, std::vector< LinearExpressionProto > times, std::vector< LinearExpressionProto > demands)
int64_t	ComputeViolation (absl::Span< const int64_t > solution) final
void	PerformMove (int, int64_t, absl::Span< const int64_t > solution_with_new_value) final
	Updates the violation with the new value.
int64_t	ViolationDelta (int var, int64_t, absl::Span< const int64_t > solution_with_new_value) final
	Returns the delta if var changes from old_value to solution[var].
std::vector< int >	UsedVariables (const CpModelProto &model_proto) const final
Public Member Functions inherited from operations_research::sat::CompiledConstraint
	CompiledConstraint ()=default
virtual	~CompiledConstraint ()=default
void	InitializeViolation (absl::Span< const int64_t > solution)
	Recomputes the violation of the constraint from scratch.
int64_t	violation () const
	The cached violation of this constraint.

Additional Inherited Members
Protected Attributes inherited from operations_research::sat::CompiledConstraint
int64_t	violation_

Constructor & Destructor Documentation

CompiledReservoirConstraint()

operations_research::sat::CompiledReservoirConstraint::CompiledReservoirConstraint ( LinearExpressionProto capacity, std::vector< std::optional< int > > is_active, std::vector< LinearExpressionProto > times, std::vector< LinearExpressionProto > demands )

inline

Definition at line 700 of file constraint_violation.h.

Member Function Documentation

ComputeViolation()

int64_t operations_research::sat::CompiledReservoirConstraint::ComputeViolation ( absl::Span< const int64_t > solution )

inlinefinalvirtual

Note

since we have our own ViolationDelta() implementation this is only used for initialization and our PerformMove(). It is why we set violations_ here.

Implements operations_research::sat::CompiledConstraint.

Definition at line 717 of file constraint_violation.h.

PerformMove()

void operations_research::sat::CompiledReservoirConstraint::PerformMove ( int var, int64_t old_value, absl::Span< const int64_t > solution_with_new_value )

inlinefinalvirtual

Updates the violation with the new value.

Todo

(user): we could probably be more incremental here, but it is a bit tricky to get right and not too important since the time is dominated by evaluating moves, not taking them.

Reimplemented from operations_research::sat::CompiledConstraint.

Definition at line 722 of file constraint_violation.h.

UsedVariables()

std::vector< int > operations_research::sat::CompiledReservoirConstraint::UsedVariables ( const CpModelProto & model_proto ) const

finalvirtual

Returns the sorted vector of variables used by this constraint. This is used to known when a violation might change, and is only called once during initialization, so speed is not to much of a concern here.

The global proto is needed to resolve interval variables reference.

Implements operations_research::sat::CompiledConstraint.

Definition at line 2264 of file constraint_violation.cc.

ViolationDelta()

int64_t operations_research::sat::CompiledReservoirConstraint::ViolationDelta ( int var, int64_t old_value, absl::Span< const int64_t > solution_with_new_value )

inlinefinalvirtual

Returns the delta if var changes from old_value to solution[var].

Reimplemented from operations_research::sat::CompiledConstraint.

Definition at line 730 of file constraint_violation.h.

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The documentation for this class was generated from the following files:

• ortools/sat/constraint_violation.h
• ortools/sat/constraint_violation.cc