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#include <stdio.h>
#include <stdlib.h>
#include <gsl/gsl_spmatrix.h>
int
main()
{
gsl_spmatrix *A = gsl_spmatrix_alloc(5, 4); /* triplet format */
gsl_spmatrix *B, *C;
size_t i, j;
/* build the sparse matrix */
gsl_spmatrix_set(A, 0, 2, 3.1);
gsl_spmatrix_set(A, 0, 3, 4.6);
gsl_spmatrix_set(A, 1, 0, 1.0);
gsl_spmatrix_set(A, 1, 2, 7.2);
gsl_spmatrix_set(A, 3, 0, 2.1);
gsl_spmatrix_set(A, 3, 1, 2.9);
gsl_spmatrix_set(A, 3, 3, 8.5);
gsl_spmatrix_set(A, 4, 0, 4.1);
printf("printing all matrix elements:\n");
for (i = 0; i < 5; ++i)
for (j = 0; j < 4; ++j)
printf("A(%zu,%zu) = %g\n", i, j,
gsl_spmatrix_get(A, i, j));
/* print out elements in triplet format */
printf("matrix in triplet format (i,j,Aij):\n");
gsl_spmatrix_fprintf(stdout, A, "%.1f");
/* convert to compressed column format */
B = gsl_spmatrix_ccs(A);
printf("matrix in compressed column format:\n");
printf("i = [ ");
for (i = 0; i < B->nz; ++i)
printf("%zu, ", B->i[i]);
printf("]\n");
printf("p = [ ");
for (i = 0; i < B->size2 + 1; ++i)
printf("%zu, ", B->p[i]);
printf("]\n");
printf("d = [ ");
for (i = 0; i < B->nz; ++i)
printf("%g, ", B->data[i]);
printf("]\n");
/* convert to compressed row format */
C = gsl_spmatrix_crs(A);
printf("matrix in compressed row format:\n");
printf("i = [ ");
for (i = 0; i < C->nz; ++i)
printf("%zu, ", C->i[i]);
printf("]\n");
printf("p = [ ");
for (i = 0; i < C->size1 + 1; ++i)
printf("%zu, ", C->p[i]);
printf("]\n");
printf("d = [ ");
for (i = 0; i < C->nz; ++i)
printf("%g, ", C->data[i]);
printf("]\n");
gsl_spmatrix_free(A);
gsl_spmatrix_free(B);
gsl_spmatrix_free(C);
return 0;
}
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