code: public static Matrix3D random(int M, int N, int K) {
          Matrix3D A = new Matrix3D(M, N, K);
          for (int i = 0; i < M; i++)
              for (int j = 0; j < N; j++)
              	for (int l = 0; l < K; l++)
              		A.data[i][j][l] = Math.random();
          return A;
      }
docs: create and return a random M-by-N matrix with values between 0 and 1