129 lines
2.7 KiB
C
129 lines
2.7 KiB
C
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/*! @file ddiagonal.c
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* \brief Auxiliary routines to work with diagonal elements
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*
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* <pre>
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* -- SuperLU routine (version 4.0) --
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* Lawrence Berkeley National Laboratory
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* June 30, 2009
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* </pre>
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*/
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#include "slu_ddefs.h"
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int dfill_diag(int n, NCformat *Astore)
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/* fill explicit zeros on the diagonal entries, so that the matrix is not
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structurally singular. */
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{
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double *nzval = (double *)Astore->nzval;
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int *rowind = Astore->rowind;
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int *colptr = Astore->colptr;
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int nnz = colptr[n];
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int fill = 0;
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double *nzval_new;
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double zero = 0.0;
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int *rowind_new;
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int i, j, diag;
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for (i = 0; i < n; i++)
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{
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diag = -1;
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for (j = colptr[i]; j < colptr[i + 1]; j++)
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if (rowind[j] == i) diag = j;
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if (diag < 0) fill++;
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}
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if (fill)
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{
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nzval_new = doubleMalloc(nnz + fill);
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rowind_new = intMalloc(nnz + fill);
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fill = 0;
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for (i = 0; i < n; i++)
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{
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diag = -1;
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for (j = colptr[i] - fill; j < colptr[i + 1]; j++)
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{
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if ((rowind_new[j + fill] = rowind[j]) == i) diag = j;
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nzval_new[j + fill] = nzval[j];
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}
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if (diag < 0)
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{
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rowind_new[colptr[i + 1] + fill] = i;
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nzval_new[colptr[i + 1] + fill] = zero;
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fill++;
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}
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colptr[i + 1] += fill;
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}
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Astore->nzval = nzval_new;
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Astore->rowind = rowind_new;
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SUPERLU_FREE(nzval);
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SUPERLU_FREE(rowind);
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}
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Astore->nnz += fill;
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return fill;
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}
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int ddominate(int n, NCformat *Astore)
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/* make the matrix diagonally dominant */
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{
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double *nzval = (double *)Astore->nzval;
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int *rowind = Astore->rowind;
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int *colptr = Astore->colptr;
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int nnz = colptr[n];
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int fill = 0;
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double *nzval_new;
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int *rowind_new;
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int i, j, diag;
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double s;
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for (i = 0; i < n; i++)
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{
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diag = -1;
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for (j = colptr[i]; j < colptr[i + 1]; j++)
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if (rowind[j] == i) diag = j;
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if (diag < 0) fill++;
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}
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if (fill)
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{
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nzval_new = doubleMalloc(nnz + fill);
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rowind_new = intMalloc(nnz+ fill);
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fill = 0;
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for (i = 0; i < n; i++)
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{
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s = 1e-6;
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diag = -1;
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for (j = colptr[i] - fill; j < colptr[i + 1]; j++)
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{
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if ((rowind_new[j + fill] = rowind[j]) == i) diag = j;
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s += fabs(nzval_new[j + fill] = nzval[j]);
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}
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if (diag >= 0) {
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nzval_new[diag+fill] = s * 3.0;
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} else {
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rowind_new[colptr[i + 1] + fill] = i;
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nzval_new[colptr[i + 1] + fill] = s * 3.0;
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fill++;
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}
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colptr[i + 1] += fill;
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}
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Astore->nzval = nzval_new;
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Astore->rowind = rowind_new;
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SUPERLU_FREE(nzval);
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SUPERLU_FREE(rowind);
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}
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else
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{
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for (i = 0; i < n; i++)
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{
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s = 1e-6;
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diag = -1;
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for (j = colptr[i]; j < colptr[i + 1]; j++)
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{
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if (rowind[j] == i) diag = j;
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s += fabs(nzval[j]);
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}
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nzval[diag] = s * 3.0;
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}
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}
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Astore->nnz += fill;
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return fill;
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}
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