docs: def factorize(self, A):
          """
          Factorizes A.
  
          Parameters
          ----------
          A : matrix
             For symmetric systems, should contain only lower diagonal part.
          """
          
          A = csc_matrix(A)
          if self.prop == self.SYMMETRIC:
              A = (A + A.T) - triu(A)
  
          self.lu = self.umfpack.splu(A)