matroid.c File Reference

#include <cmr/matroid.h>
#include "env_internal.h"
#include "seymour_internal.h"
#include "matrix_internal.h"
#include "listmatrix.h"
#include "linear_algebra_internal.h"
#include <assert.h>
#include <string.h>

Functions
static CMR_ERROR	computePivots (CMR *cmr, CMR_CHRMAT *matrix, size_t numPivots, size_t *pivotRows, size_t *pivotColumns, int characteristic, CMR_SUBMAT **pviolator, CMR_CHRMAT **presult)
	Carries out numPivots pivots on matrix and stores the result in *presult.
CMR_ERROR	CMRchrmatBinaryPivot (CMR *cmr, CMR_CHRMAT *matrix, size_t pivotRow, size_t pivotColumn, CMR_CHRMAT **presult)
	Apply a pivot to matrix and returns the resulting matrix in *presult.
CMR_ERROR	CMRchrmatTernaryPivot (CMR *cmr, CMR_CHRMAT *matrix, size_t pivotRow, size_t pivotColumn, CMR_CHRMAT **presult)
	Applies a pivot to matrix and returns the resulting matrix in *presult.
CMR_ERROR	CMRchrmatRegularPivot (CMR *cmr, CMR_CHRMAT *matrix, size_t pivotRow, size_t pivotColumn, CMR_SUBMAT **pviolator, CMR_CHRMAT **presult)
	Applies a pivot to matrix and returns the resulting matrix in *presult.
CMR_ERROR	CMRchrmatBinaryPivots (CMR *cmr, CMR_CHRMAT *matrix, size_t numPivots, size_t *pivotRows, size_t *pivotColumns, CMR_CHRMAT **presult)
	Applies a sequence of pivots to matrix and returns the resulting matrix in *presult.
CMR_ERROR	CMRchrmatTernaryPivots (CMR *cmr, CMR_CHRMAT *matrix, size_t numPivots, size_t *pivotRows, size_t *pivotColumns, CMR_CHRMAT **presult)
	Applies a sequence of pivots to matrix and returns the resulting matrix in *presult.
CMR_ERROR	CMRchrmatRegularPivots (CMR *cmr, CMR_CHRMAT *matrix, size_t numPivots, size_t *pivotRows, size_t *pivotColumns, CMR_SUBMAT **pviolator, CMR_CHRMAT **presult)
	Applies a sequence of pivots to matrix and returns the resulting matrix in *presult.
CMR_ERROR	CMRminorCreate (CMR *cmr, CMR_MINOR **pminor, size_t numPivots, CMR_SUBMAT *submatrix, CMR_MINOR_TYPE type)
	Creates a minor, allocating space for numPivots pivots and a remaining submatrix.
CMR_ERROR	CMRminorFree (CMR *cmr, CMR_MINOR **pminor)
	Frees the minor *pminor (if pminor is not NULL).
CMR_MINOR_TYPE	CMRminorType (CMR_MINOR *minor)
	Returns the type of minor.
size_t	CMRminorNumPivots (CMR_MINOR *minor)
	Returns the number of pivots needed to make a minor visible.
size_t *	CMRminorPivotRows (CMR_MINOR *minor)
	Returns the array with pivot rows to make a minor visible.
size_t *	CMRminorPivotColumns (CMR_MINOR *minor)
	Returns the array with pivot columns to make a minor visible.
CMR_SUBMAT *	CMRminorSubmatrix (CMR_MINOR *minor)
	Returns the submatrix to take (after applying pivots) to make a minor visible.
CMR_ERROR	CMRminorPrint (CMR *cmr, CMR_MINOR *minor, size_t numRows, size_t numColumns, FILE *stream)
	Writes the minor minor to stream by means of lists of row and column indices as well as pivot entries.
CMR_ERROR	CMRminorWriteToFile (CMR *cmr, CMR_MINOR *minor, size_t numRows, size_t numColumns, const char *fileName)
	Writes the minor minor to the file fileName by means of lists of row and column indices as well as pivot entries.

Function Documentation

computePivots()

static CMR_ERROR computePivots ( CMR *  cmr, CMR_CHRMAT *  matrix, size_t  numPivots, size_t *  pivotRows, size_t *  pivotColumns, int  characteristic, CMR_SUBMAT **  pviolator, CMR_CHRMAT **  presult  )

static

Carries out numPivots pivots on matrix and stores the result in *presult.

Calculations are done modulo characteristic. If that value is negative then the pivots must be regular, i.e., over every field. If the result would differ over fields, *presult will be NULL and, if given, *pviolator will refer to the submatrix indexed by an affected entry as well as indices of all previous pivots.

Parameters

cmr	CMR environment .
matrix	Input matrix.
numPivots	Number of pivots.
pivotRows	Row indices of pivots.
pivotColumns	Column indices of pivots.
characteristic	Characteristic of field.
pviolator	Pointer for storing a violating (irregular) submatrix; may be NULL.
presult	Pointer for storing the resulting matrix.