code: private void mmuli(int n, double[] A, double[] B, double[] C) {
          for (int i = 0; i < n * n; i++) {
              C[i] = 0;
          }
  
          for (int j = 0; j < n; j++) {
              int jn = j * n;
              for (int k = 0; k < n; k++) {
                  int kn = k * n;
                  double bkjn = B[k + jn];
                  for (int i = 0; i < n; i++) {
                      C[i + jn] += A[i + kn] * bkjn;
                  }
              }
          }
      }
docs: Compute C = A * B