[Help-gsl] basic question about using gsl matrix types

[Alan Mead]

I'm new to GSL and fairly new to C and I have a beginner's question. I'm 
using GSL 1.10 on Fedora 9 with gcc 4.3.0.

How do I change line 14 and/or 19 (marked below) to avoid these warnings 
about "conflicting types for ‘my_print_matrix’"? The GSL docs (section 
8.4.5) say " pointer ... const gsl_matrix * can be obtained by taking 
the address of the matrix component with the & operator." So, shouldn't 
I write "&a.matrix" on line 14?

Please let me know if this is not an appropriate question for this list.

-Alan

address@hidden examples]$ gcc -Wall -Wextra -lgsl -lgslcblas simple.c -o simple
simple.c: In function ‘main’:
simple.c:14: warning: implicit declaration of function ‘my_print_matrix’
simple.c: At top level:
simple.c:19: warning: conflicting types for ‘my_print_matrix’
simple.c:14: warning: previous implicit declaration of ‘my_print_matrix’ 
was here
address@hidden examples]$ ./simple
Matrix A (6 x 3):
0.180 0.600 0.570
0.410 0.240 0.990
0.110 0.140 0.190
0.210 0.240 0.290
0.140 0.300 0.970
0.510 0.130 0.190
address@hidden examples]$ cat simple.c
#include <stdio.h>
#include <gsl/gsl_linalg.h>

int
main (void)
{
double a_data[] = { 0.18, 0.60, 0.57,
0.41, 0.24, 0.99,
0.11, 0.14, 0.19,
0.21, 0.24, 0.29,
0.14, 0.30, 0.97,
0.51, 0.13, 0.19 };
gsl_matrix_view a = gsl_matrix_view_array (a_data, 6, 3);
my_print_matrix ( &a.matrix, "A", 6, 3); // line 14
return 0;
}

void
my_print_matrix( const gsl_matrix * m, char * name, int rows, int cols ) 
{ // line 19
int r,c;

printf ("Matrix %s (%d x %d):\n", name, rows, cols );
for( r = 0; r < rows; r++ ) {
for( c = 0; c < cols; c++ ) {
printf ("%8.3f", gsl_matrix_get (m, r, c));
}
printf ("\n");
}
}

--
Alan D. Mead, Ph.D. 
Assistant Professor, Institute of Psychology
Scientific Adviser, Center for Research and Service
Illinois Institute of Technology
3101 South Dearborn, 2nd floor
Chicago IL 60616