code: public static Basic1DMatrix random(int rows, int columns, Random random) {
          double[] array = new double[rows * columns];
  
          for (int i = 0; i < rows * columns; i++) {
              array[i] = random.nextDouble();
          }
  
          return new Basic1DMatrix(rows, columns, array);
      }
docs: Creates a random {@link Basic1DMatrix} of the given shape:
  {@code rows} x {@code columns}.