矩陣宣告

#include <gsl/gsl_matrix.h>

gsl_matrix *m = gsl_matrix_alloc(6,5);  //橫列數,直行數

double a[] = {1,2,3,4,5,
              2,4,6,8,10,
              3,6,9,12,15,
              4,8,12,16,20,
              5,10,15,20,25,
              6,12,18,24,30};

SetMat(m,a)  //賦值
PrintMat(m);  // 輸出

/*

typedef struct
{
  size_t size1;     // # of rows
  size_t size2;     // # of columns
  size_t tda;
  double * data;    // the location of the first element of the matrix in memory
  gsl_block * block;
  int owner;
} gsl_matrix;

*/

void SetMat(gsl_matrix *m, double n[]){
    //if( m->size1*m->size2 != (int)(sizeof(n)/sizeof(n[0]))){
    //    printf("Error: Set Matrix Mismatchd! gsl_len is %d and input array is %d.\\n",
    //        m->size1*m->size2,
    //        (int)(sizeof(n)/sizeof(n[0])));
    //    exit(0);
    //}
    for(int i=0;i<m->size1;i++){
        for(int j=0;j<m->size2;j++){
            gsl_matrix_set (m, i, j, *n++);
        }
    }
}

或是

// more easy way!

double a[] = {1,2,3,4,5,
              2,4,6,8,10,
              3,6,9,12,15,
              4,8,12,16,20,
              5,10,15,20,25,
              6,12,18,24,30};

gsl_matrix_view m = gsl_matrix_view_array(a, 6, 5);  // 橫列數,直行數
PrintMat(&m.matrix);  // 輸出

矩陣輸出

void PrintMat(gsl_matrix *m){
    printf("Print Matrix: \\n");
    for(int i=0; i<m->size1;i++){
        for(int j=0;j<m->size2;j++){
            //printf(j==m->size2-1 ? "%6.3f\\n" : "%6.3f ", gsl_matrix_get(m,i,j));
            printf(j==m->size2-1?"%6.2f\\n":"%6.2f\\t", gsl_matrix_get(m,i,j));
        }
    }
}