umfpack_col_to_triplet.c
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/* ========================================================================== */
/* === UMFPACK_col_to_triplet =============================================== */
/* ========================================================================== */
/* -------------------------------------------------------------------------- */
/* UMFPACK Copyright (c) Timothy A. Davis, CISE, */
/* Univ. of Florida. All Rights Reserved. See ../Doc/License for License. */
/* web: http://www.cise.ufl.edu/research/sparse/umfpack */
/* -------------------------------------------------------------------------- */
/*
User callable. Converts a column-oriented input matrix to triplet form by
constructing the column indices Tj from the column pointers Ap. The matrix
may be singular. See umfpack_col_to_triplet.h for details.
*/
#include "umf_internal.h"
GLOBAL Int UMFPACK_col_to_triplet
(
Int n_col,
const Int Ap [ ],
Int Tj [ ]
)
{
/* ---------------------------------------------------------------------- */
/* local variables */
/* ---------------------------------------------------------------------- */
Int nz, j, p, p1, p2, length ;
/* ---------------------------------------------------------------------- */
/* construct the column indices */
/* ---------------------------------------------------------------------- */
if (!Ap || !Tj)
{
return (UMFPACK_ERROR_argument_missing) ;
}
if (n_col <= 0)
{
return (UMFPACK_ERROR_n_nonpositive) ;
}
if (Ap [0] != 0)
{
return (UMFPACK_ERROR_invalid_matrix) ;
}
nz = Ap [n_col] ;
if (nz < 0)
{
return (UMFPACK_ERROR_invalid_matrix) ;
}
for (j = 0 ; j < n_col ; j++)
{
p1 = Ap [j] ;
p2 = Ap [j+1] ;
length = p2 - p1 ;
if (length < 0 || p2 > nz)
{
return (UMFPACK_ERROR_invalid_matrix) ;
}
for (p = p1 ; p < p2 ; p++)
{
Tj [p] = j ;
}
}
return (UMFPACK_OK) ;
}