[math] Matrix get value at row, column index

src/matrix.c

@@ -1,6 +1,5 @@
 #include "matrix.h"
 
-
 matrix_t *matrix_new(size_t m, size_t n) {
     matrix_t *matrix = malloc(sizeof(matrix_t));
 
@@ -50,6 +49,11 @@ inline void matrix_set_scalar(matrix_t *self, size_t row_index, size_t col_index
     values[offset] = value;
 }
 
+inline double matrix_get(matrix_t *self, size_t row_index, size_t col_index) {
+    size_t index = row_index * self->n + col_index;
+    return self->values->a[index];
+}
+
 inline matrix_t *matrix_new_value(size_t m, size_t n, double value) {
     matrix_t *matrix = matrix_new(m, n);
     matrix_set(matrix, value);