code: public static Basic2DMatrix random(int rows, int columns, Random random) {
          double[][] array = new double[rows][columns];
  
          for (int i = 0; i < rows; i++) {
              for (int j = 0; j < columns; j++) {
                  array[i][j] = random.nextDouble();
              }
          }
  
          return new Basic2DMatrix(array);
      }
docs: Creates a random {@link Basic2DMatrix} of the given shape:
  {@code rows} x {@code columns}.