#include <reduced_costs.h>

Public Member Functions
	PrimalPrices (absl::BitGenRef random, const VariablesInfo &variables_info, PrimalEdgeNorms primal_edge_norms, ReducedCosts reduced_costs)

ColIndex	GetBestEnteringColumn ()

void	UpdateBeforeBasisPivot (ColIndex entering_col, UpdateRow *update_row)

void	RecomputePriceAt (ColIndex col)
	Triggers a recomputation of the price at the given column only.

void	SetAndDebugCheckThatColumnIsDualFeasible (ColIndex col)

void	ForceRecomputation ()

Detailed Description

Maintains the list of dual infeasible positions and their associated prices.

Todo: (user): Not high priority but should probably be moved to its own file.

Definition at line 299 of file reduced_costs.h.

Constructor & Destructor Documentation

◆ PrimalPrices()

operations_research::glop::PrimalPrices::PrimalPrices	(	absl::BitGenRef	random,
		const VariablesInfo &	variables_info,
		PrimalEdgeNorms *	primal_edge_norms,
		ReducedCosts *	reduced_costs )

Takes references to what we need.

Todo: (user): Switch to a model based API like in CP-SAT.

Definition at line 527 of file reduced_costs.cc.

Member Function Documentation

◆ ForceRecomputation()

void operations_research::glop::PrimalPrices::ForceRecomputation ( )

inline

If the incremental updates are not properly called for a while, then it is important to make sure that the prices will be recomputed the next time GetBestEnteringColumn() is called.

Definition at line 326 of file reduced_costs.h.

◆ GetBestEnteringColumn()

ColIndex operations_research::glop::PrimalPrices::GetBestEnteringColumn ( )

Returns the best candidate out of the dual infeasible positions to enter the basis during a primal simplex iterations.

Definition at line 577 of file reduced_costs.cc.

◆ RecomputePriceAt()

void operations_research::glop::PrimalPrices::RecomputePriceAt ( ColIndex col )

Triggers a recomputation of the price at the given column only.

Definition at line 555 of file reduced_costs.cc.

◆ SetAndDebugCheckThatColumnIsDualFeasible()

void operations_research::glop::PrimalPrices::SetAndDebugCheckThatColumnIsDualFeasible ( ColIndex col )

Same than RecomputePriceAt() for the case where we know the position is dual feasible.

If we need a recomputation, we cannot assumes that the reduced costs are valid until we are about to recompute the prices.

Definition at line 568 of file reduced_costs.cc.

◆ UpdateBeforeBasisPivot()

void operations_research::glop::PrimalPrices::UpdateBeforeBasisPivot	(	ColIndex	entering_col,
		UpdateRow *	update_row )

Similar to the other UpdateBeforeBasisPivot() functions.

Important: Both the primal norms and reduced costs must have been updated before this is called.

If we are recomputing everything when requested, no need to update.

Note: the set of positions works because both the reduced costs and the primal edge norms are updated on the same positions which are given by the update_row.

This should be redundant with the call above, except in degenerate cases where the update_row has a zero position on the entering col!

Definition at line 539 of file reduced_costs.cc.

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

ortools/glop/reduced_costs.h
ortools/glop/reduced_costs.cc

Public Member Functions