code: def calc_inc(self):
          
          system = self.system
          self.newton_call()
  
          A = sparse([[system.dae.Fx, system.dae.Gx],
                      [system.dae.Fy, system.dae.Gy]])
  
          inc = matrix([system.dae.f, system.dae.g])
  
          if system.dae.factorize:
              self.F = self.solver.symbolic(A)
              system.dae.factorize = False
  
          try:
              N = self.solver.numeric(A, self.F)
              self.solver.solve(A, self.F, N, inc)
          except ValueError:
              logger.warning('Unexpected symbolic factorization.')
              system.dae.factorize = True
          except ArithmeticError:
              logger.warning('Jacobian matrix is singular.')
              system.dae.check_diag(system.dae.Gy, 'unamey')
  
          return -inc
docs: Calculate the Newton incrementals for each step
  
          Returns
          -------
          matrix
              The solution to ``x = -A\\b``