cholmod_timing.cpp

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#include "cholmod.h"
#include "sba/sba.h"
#include <time.h>
#define CPUTIME ((double) (clock ( )) / CLOCKS_PER_SEC)

int main (void)
{
    cholmod_sparse *A ;
    cholmod_dense *x, *b, *r ;
    cholmod_factor *L ;
    double one [2] = {1,0}, m1 [2] = {-1,0} ;       /* basic scalars */
    cholmod_common c ;
    cholmod_start (&c) ;                            /* start CHOLMOD */
    A = cholmod_read_sparse (stdin, &c) ;           /* read in a matrix */
    cholmod_print_sparse (A, "A", &c) ;             /* print the matrix */
    if (A == NULL || A->stype == 0)                 /* A must be symmetric */
    {
        cholmod_free_sparse (&A, &c) ;
        cholmod_finish (&c) ;
        return (0) ;
    }
    b = cholmod_ones (A->nrow, 1, A->xtype, &c) ;   /* b = ones(n,1) */
    double t0 = CPUTIME;
    L = cholmod_analyze (A, &c) ;                   /* analyze */
    cholmod_factorize (A, L, &c) ;                  /* factorize */
    x = cholmod_solve (CHOLMOD_A, L, b, &c) ;       /* solve Ax=b */
    double t1 = CPUTIME;
    printf("Time: %12.4f \n", t1-t0);
    r = cholmod_copy_dense (b, &c) ;                /* r = b */
    cholmod_sdmult (A, 0, m1, one, x, r, &c) ;      /* r = r-Ax */
    printf ("norm(b-Ax) %8.1e\n",
            cholmod_norm_dense (r, 0, &c)) ;        /* print norm(r) */
    cholmod_free_factor (&L, &c) ;                  /* free matrices */
    cholmod_free_sparse (&A, &c) ;
    cholmod_free_dense (&r, &c) ;
    cholmod_free_dense (&x, &c) ;
    cholmod_free_dense (&b, &c) ;
    cholmod_finish (&c) ;                           /* finish CHOLMOD */
    return (0) ;
}