current["nadir"] and current["ideal"] are NoneType

Hello,

When I use the default termination, I got below error:

 File "/home/dev/miniconda3/envs/dev/lib/python3.10/site-packages/pymoo/core/algorithm.py", line 309, in _post_advance 
                                      self.termination.update(self)                                                                                                                           
File "/home/dev/miniconda3/envs/dev/lib/python3.10/site-packages/pymoo/core/termination.py", line 28, in update
                                             progress = self._update(algorithm)                                                                                                                      
File "/home/dev/miniconda3/envs/dev/lib/python3.10/site-packages/pymoo/termination/default.py", line 24, in _update 
                                        p = [criterion.update(algorithm) for criterion in self.criteria]                                                                                        
File "/home/dev/miniconda3/envs/dev/lib/python3.10/site-packages/pymoo/termination/default.py", line 24, in <listcomp>
                                      p = [criterion.update(algorithm) for criterion in self.criteria]                                                                                        
File "/home/dev/miniconda3/envs/dev/lib/python3.10/site-packages/pymoo/core/termination.py", line 28, in update 
                                            progress = self._update(algorithm)                                                                                                                      
File "/home/dev/miniconda3/envs/dev/lib/python3.10/site-packages/pymoo/termination/robust.py", line 32, in _update
                                          perc = self.termination.update(algorithm)                                                                                                               
File "/home/dev/miniconda3/envs/dev/lib/python3.10/site-packages/pymoo/core/termination.py", line 28, in update 
                                            progress = self._update(algorithm)                                                                                                                      
File "/home/dev/miniconda3/envs/dev/lib/python3.10/site-packages/pymoo/termination/delta.py", line 42, in _update 
                                          delta = self._delta(prev, current)                                                                                                                      
File "/home/dev/miniconda3/envs/dev/lib/python3.10/site-packages/pymoo/termination/ftol.py", line 71, in _delta 
                                            norm = current["nadir"] - current["ideal"]                                                                                                            
TypeError: unsupported operand type(s) for -: 'NoneType' and 'NoneType'

How to fix the None issue and why did it come out? Thanks!

[humana]

Yeah, I have the same problem. Don’t think this code is tested very well. What I basically did was add some checks to make sure those values exist. I don’t know if this is entirely correct, as I’ve seen many times that ftol is reached, but it just doesn’t converge. I’m guessing it’s because of these conditions.

def _delta(self, prev, current):

        if not (prev["feas"] and current["feas"]):
            return np.inf

        if prev["nadir"] is None or prev["ideal"] is None:
            return np.inf

        if current["nadir"] is None or current["ideal"] is None:
            return np.inf

[blankjul]

Sorry for the delay. That was indeed a bug which should be fixed now!