mlir::presburger::GBRSimplex Class Reference

Given a simplex for a polytope, construct a new simplex whose variables are identified with a pair of points (x, y) in the original polytope. More...

Public Member Functions
	GBRSimplex (const Simplex &originalSimplex)
void	addEqualityForDirection (ArrayRef< MPInt > dir)
	Add an equality dotProduct(dir, x - y) == 0. More...
Fraction	computeWidth (ArrayRef< MPInt > dir)
	Compute max(dotProduct(dir, x - y)). More...
Fraction	computeWidthAndDuals (ArrayRef< MPInt > dir, SmallVectorImpl< MPInt > &dual, MPInt &dualDenom)
	Compute max(dotProduct(dir, x - y)) and save the dual variables for only the direction equalities to dual. More...
void	removeLastEquality ()
	Remove the last equality that was added through addEqualityForDirection. More...

Detailed Description

Given a simplex for a polytope, construct a new simplex whose variables are identified with a pair of points (x, y) in the original polytope.

Supports some operations needed for generalized basis reduction. In what follows, dotProduct(x, y) = x_1 * y_1 + x_2 * y_2 + ... x_n * y_n where n is the dimension of the original polytope.

This supports adding equality constraints dotProduct(dir, x - y) == 0. It also supports rolling back this addition, by maintaining a snapshot stack that contains a snapshot of the Simplex's state for each equality, just before that equality was added.

Definition at line 1648 of file Simplex.cpp.

Constructor & Destructor Documentation

GBRSimplex()

mlir::presburger::GBRSimplex::GBRSimplex ( const Simplex &  originalSimplex )

inline

Definition at line 1652 of file Simplex.cpp.

Member Function Documentation

addEqualityForDirection()

void mlir::presburger::GBRSimplex::addEqualityForDirection ( ArrayRef< MPInt >  dir )

inline

Add an equality dotProduct(dir, x - y) == 0.

First pushes a snapshot for the current simplex state to the stack so that this can be rolled back later.

Definition at line 1659 of file Simplex.cpp.

computeWidth()

Fraction mlir::presburger::GBRSimplex::computeWidth ( ArrayRef< MPInt >  dir )

inline

Compute max(dotProduct(dir, x - y)).

Definition at line 1666 of file Simplex.cpp.

References mlir::presburger::MaybeOptimum< T >::isBounded().

computeWidthAndDuals()

Fraction mlir::presburger::GBRSimplex::computeWidthAndDuals ( ArrayRef< MPInt >  dir, SmallVectorImpl< MPInt > &  dual, MPInt &  dualDenom  )

inline

Compute max(dotProduct(dir, x - y)) and save the dual variables for only the direction equalities to dual.

Definition at line 1675 of file Simplex.cpp.

References mlir::presburger::MaybeOptimum< T >::isBounded(), and mlir::presburger::Simplex::Up.

removeLastEquality()

void mlir::presburger::GBRSimplex::removeLastEquality ( )

inline

Remove the last equality that was added through addEqualityForDirection.

We do this by rolling back to the snapshot at the top of the stack, which should be a snapshot taken just before the last equality was added.

Definition at line 1734 of file Simplex.cpp.

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

• lib/Analysis/Presburger/Simplex.cpp