def get_deter
    Error.call "Matrix::get_deter : This error comes from get_deter which works only with 2x2 matrix" if @columns != 2 or @lines != 2

    det = get_val(0, 0).to_i * get_val(1, 1).to_i
    det -= get_val(0, 1).to_i * get_val(1, 0).to_i
    return det
  end
def get_deter
    Error.call "Matrix::get_deter : This error comes from get_deter which works only with 2x2 matrix" if @columns != 2 or @lines != 2

    det = get_val(0, 0).to_i * get_val(1, 1).to_i
    det -= get_val(0, 1).to_i * get_val(1, 0).to_i
    return det
  end
== Returns::
   Numerical value which is the determinant of the matrix. It only work on 2x2