xbt_matrix_t xbt_matrix_double_new_zeros(int lines, int rows) {
xbt_matrix_t res = xbt_matrix_new(lines, rows,sizeof(double),NULL);
xbt_matrix_t xbt_matrix_double_new_zeros(int lines, int rows) {
xbt_matrix_t res = xbt_matrix_new(lines, rows,sizeof(double),NULL);