Question

double a[] = { 0.11, 0.12, 0.13,
                  0.21, 0.22, 0.23 };

   double b[] = { 1011, 1012,
                  1021, 1022,
                  1031, 1032 };

   double c[] = { 0.00, 0.00,
                  0.00, 0.00 };

   gsl_matrix_view A = gsl_matrix_view_array(a, 2, 3);
   gsl_matrix_view B = gsl_matrix_view_array(b, 3, 2);
   gsl_matrix_view C = gsl_matrix_view_array(c, 2, 2);

   /* Compute C = A B */

   gsl_blas_dgemm (CblasNoTrans, CblasNoTrans,
                   1.0, &A.matrix, &B.matrix,
                   0.0, &C.matrix);

how do I deallocate the memory assigned to the matrices?

Answer 1

The compiler will take care of those matrices. Unless you use malloc()/new[] or any function that uses malloc()/new[] and gives you ownership of the allocated memory there’re no chances to leak memory.

If you asked about gsl_matrix_view_array() – the documentation says that the return value is a pointer to a view in the original matrix which means that no extra matrix is allocated – you only get a pointer into the same matrix. So unless you used malloc()/new to allocate the original matrix you shouldn’t do anything. If you use malloc()/new[] for the original matrix (not your case, but anyway) – call free()/delete[] on the original matrix, not on a view.