GSL(Gnu Scientific Library)을 이용중 bug 해결을 위한 질문입니다.

2.5     2.4
0.5     0.7
2.2     2.9
1.9     2.2
3.1     3.0
2.3     2.7
2       1.6
1       1.1
1.5     1.6
1.1     0.9

#include <stdio.h >
#include <string.h>
#include <gsl/gsl_matrix.h>
 
#define MAX_LINE_LENGTH 80
 
int get_num_column(FILE* file_ptr) {
    char line[MAX_LINE_LENGTH];
    char delimiters[] = " \f\n\r\t\v"; // standard whitespace characters
    char* ch_ptr;
    int i=0;  //counter
 
    fgets(line, sizeof(line), file_ptr);
    //printf("%s\n",line);
    ch_ptr = strtok(line, delimiters);
    while(ch_ptr != NULL) {
        //printf("%s\n",pch);
        ch_ptr = strtok(NULL, delimiters);
        i++;
    }
    //printf("%d\n",i);
    rewind(file_ptr); /* reset the file pointer's position */
    return i;
}
 
int get_num_row(FILE* file_ptr) {
    char line[MAX_LINE_LENGTH];
    int i=0;
    while (fgets(line, sizeof(line), file_ptr) != NULL) {
        //printf("%s\n",line);
        i++;
    }
    rewind(file_ptr); /* reset the file pointer's position */
    return i;
}
 
int main(void) {
    FILE* file_ptr;
    file_ptr=fopen("./sample.dat","r");
 
    if(file_ptr==NULL) {
        printf("Error: cannot open a file.\n");
        /* fclose(file); DON'T PASS A NULL POINTER TO fclose !! */
        return 1;
    }
 
    //***** get the size of data
    const int num_column = get_num_column(file_ptr);
    const int num_row    = get_num_row(file_ptr);  
 
    printf("Num of Columns = %d\n",get_num_column(file_ptr));
    printf("Num of Rows    = %d\n",get_num_row(file_ptr));   
 
    gsl_matrix* m = gsl_matrix_calloc(num_row, num_column);
    gsl_matrix_fscanf(file_ptr, m);
 
    // check out loaded data
    int i,j;
    for (j = 0; j < num_column; j++) {
        printf("%i th column:\n", j);
        for (i = 0; i < num_row; i++) {
            printf("%g\n", gsl_matrix_get(m, i, j));
        }
        printf("\n");
    }
 
    //***** read data   
    //get_data(file_ptr,m);
 
 
    //**** mean
    gsl_vector* column = gsl_vector_calloc(num_row);
    gsl_matrix_get_col(column, m, 0);
    // check out loaded data
    for (i = 0; i < num_row; i++) {
        printf("%g\n", gsl_vector_get(column, i));
    }
    printf("\n");
    for (i = 0; i < num_row; i++) {
        printf("%g\n", column->data[i]);
    }
    //double gsl_stats_mean (const double data[], size_t stride, size_t n)
    double mean = gsl_stats_mean(column->data, 1, num_row);
    printf("mean = %g\n", mean);
 
    gsl_vector_free(column);
    gsl_matrix_free(m);
    return 0;
}
 
뭔가 함수 인자의 data type에서 문제가 생기지 않았나 싶은데, GSL manual을 대조해 보아도 특별히 잘못된 점을 찾지 못하였습니다.
뭔가 조언이라도 주시면 감사하겠습니다.