public Vector getRow(final int row) {
    validate(row, height);
    return new Vector.Modified(vector) {
      @Override
      public double get(int column) {
        validate(column, width);
        return super.get(column + row * width);
      }

      @Override
      public int getSize() {
        return width;
      }
    };
  }
public Vector getRow(final int row)