#define M 3
#define N 3
int main() {
/* singular matrix rank(a) == 1 */
array double a[M][N] = {1, 2, 3,
1, 2, 3,
2, 4, 6};
int r = rank(a);
array double orth[M][r];
orthonormalbase(a, orth);
printf("rank(a) = %d\n", r);
printf("orth from orthonormalbase(a, orth) = \n%f\n", orth);
printf("transpose(orth)*orth = \n%f\n", transpose(orth)*orth);
}
rank(a) = 1
orth from orthonormalbase(a, orth) =
-0.408248
-0.408248
-0.816497
transpose(orth)*orth =
1.000000