def add_col_mult(self, vec, mult, target=None):
    """
    Add a multiple of vector vec to every column of the matrix. If a target
    is provided, it is used to store the result instead of self.
    """

    if not target:
      target = self

    err_code = _eigenmat.add_col_mult(self.p_mat, vec.p_mat, target.p_mat, ct.c_float(mult))
    if err_code:
      raise generate_exception(err_code)

    return target

    Add a multiple of vector vec to every column of the matrix. If a target
    is provided, it is used to store the result instead of self.
    
eigenmat/eigenmat.py