dreadtriple.c

SuperLU is a general purpose library for the direct solution of large, sparse, nonsymmetric systems

#include <stdio.h>
#include "slu_ddefs.h"
#include "slu_util.h"


void
dreadtriple(int *m, int *n, int *nonz,
	    double **nzval, int **rowind, int **colptr)
{
/*
 * Output parameters
 * =================
 *   (a,asub,xa): asub[*] contains the row subscripts of nonzeros
 *	in columns of matrix A; a[*] the numerical values;
 *	row i of A is given by a[k],k=xa[i],...,xa[i+1]-1.
 *
 */
    int    i, j, k, jsize, lasta, nnz, nz;
    double *a, *val;
    int    *asub, *xa, *row, *col;
    
    /* 	Matrix format:
     *    First line:  #rows, #cols, #non-zero
     *    Triplet in the rest of lines:
     *                 row, col, value
     */

    scanf("%d%d", n, nonz);
    *m = *n;
    printf("m %d, n %d, nonz %d\n", *m, *n, *nonz);
    dallocateA(*n, *nonz, nzval, rowind, colptr); /* Allocate storage */
    a    = *nzval;
    asub = *rowind;
    xa   = *colptr;

    val = (double *) SUPERLU_MALLOC(*nonz * sizeof(double));
    row = (int *) SUPERLU_MALLOC(*nonz * sizeof(int));
    col = (int *) SUPERLU_MALLOC(*nonz * sizeof(int));

    for (j = 0; j < *n; ++j) xa[j] = 0;

    /* Read into the triplet array from a file */
    for (nnz = 0, nz = 0; nnz < *nonz; ++nnz) {
	scanf("%d%d%lf\n", &row[nz], &col[nz], &val[nz]);
	/* Change to 0-based indexing. */
#if 0
	--row[nz];
	--col[nz];
#endif
	if (row[nz] < 0 || row[nz] >= *m || col[nz] < 0 || col[nz] >= *n
	    /*|| val[nz] == 0.*/) {
	    fprintf(stderr, "nz %d, (%d, %d) = %e out of bound, removed\n", 
		    nz, row[nz], col[nz], val[nz]);
	    exit(-1);
	} else {
	    ++xa[col[nz]];
	    ++nz;
	}
    }

    *nonz = nz;

    /* Initialize the array of column pointers */
    k = 0;
    jsize = xa[0];
    xa[0] = 0;
    for (j = 1; j < *n; ++j) {
	k += jsize;
	jsize = xa[j];
	xa[j] = k;
    }
    
    /* Copy the triplets into the column oriented storage */
    for (nz = 0; nz < *nonz; ++nz) {
	j = col[nz];
	k = xa[j];
	asub[k] = row[nz];
	a[k] = val[nz];
	++xa[j];
    }

    /* Reset the column pointers to the beginning of each column */
    for (j = *n; j > 0; --j)
	xa[j] = xa[j-1];
    xa[0] = 0;

    SUPERLU_FREE(val);
    SUPERLU_FREE(row);
    SUPERLU_FREE(col);

#ifdef CHK_INPUT
    for (i = 0; i < *n; i++) {
	printf("Col %d, xa %d\n", i, xa[i]);
	for (k = xa[i]; k < xa[i+1]; k++)
	    printf("%d\t%16.10f\n", asub[k], a[k]);
    }
#endif

}


void dreadrhs(int m, double *b)
{
    FILE *fp, *fopen();
    int i, j;

    if ( !(fp = fopen("b.dat", "r")) ) {
        fprintf(stderr, "dreadrhs: file does not exist\n");
	exit(-1);
    }
    for (i = 0; i < m; ++i)
      fscanf(fp, "%lf\n", &b[i]);
      /*fscanf(fp, "%d%lf\n", &j, &b[i]);*/
    /*        readpair_(j, &b[i]);*/
    fclose(fp);
}