Fix anyoptimization#368: Multi-objective Optimization With Mixed Vari…

…ables (multipl)

Dealing with numpy arrays of fixed length has caused an issue when setting longer strings.

pymoo/core/mixed.py

@@ -1,4 +1,5 @@
 import math
+from copy import deepcopy
 
 import numpy as np
 
@@ -10,7 +11,7 @@
 from pymoo.core.population import Population
 from pymoo.core.problem import Problem
 from pymoo.core.sampling import Sampling
-from pymoo.core.variable import Choice, Real, Integer, Binary
+from pymoo.core.variable import Choice, Real, Integer, Binary, BoundedVariable
 from pymoo.operators.crossover.sbx import SBX
 from pymoo.operators.crossover.ux import UX
 from pymoo.operators.mutation.bitflip import BFM
@@ -96,12 +97,9 @@ def _do(self, problem, pop, n_offsprings, parents=False, **kwargs):
             _parents = [[Individual(X=np.array([parent.X[var] for var in list_of_vars])) for parent in parents] for
                         parents in pop]
 
-            _vars = [vars[e] for e in list_of_vars]
-            _xl, _xu = None, None
-
-            if clazz in [Real, Integer]:
-                _xl, _xu = np.array([v.bounds for v in _vars]).T
-
+            _vars = {e: vars[e] for e in list_of_vars}
+            _xl = np.array([vars[e].lb if hasattr(vars[e], "lb") else None for e in list_of_vars])
+            _xu = np.array([vars[e].ub if hasattr(vars[e], "ub") else None for e in list_of_vars])
             _problem = Problem(vars=_vars, xl=_xl, xu=_xu)
 
             _off = crossover(_problem, _parents, **kwargs)

pymoo/core/problem.py

@@ -130,8 +130,11 @@ def __init__(self,
         if vars is not None:
             self.vars = vars
             self.n_var = len(vars)
-            self.xl = {name: var.lb if hasattr(var, "lb") else None for name, var in vars.items()}
-            self.xu = {name: var.ub if hasattr(var, "ub") else None for name, var in vars.items()}
+
+            if self.xl is None:
+                self.xl = {name: var.lb if hasattr(var, "lb") else None for name, var in vars.items()}
+            if self.xu is None:
+                self.xu = {name: var.ub if hasattr(var, "ub") else None for name, var in vars.items()}
 
         # the variable type (only as a type hint at this point)
         self.vtype = vtype

pymoo/operators/mutation/rm.py

@@ -8,12 +8,16 @@ class ChoiceRandomMutation(Mutation):
     def _do(self, problem, X, **kwargs):
         assert problem.vars is not None
 
+        # ensure the type object (fixed string length <UX can cause issues)
+        X = X.astype(object)
+
         prob_var = self.get_prob_var(problem, size=len(X))
 
-        for k in range(problem.n_var):
-            var = problem.vars[k]
+        for k, (_, var) in enumerate(problem.vars.items()):
             mut = np.where(np.random.random(len(X)) < prob_var)[0]
-            X[mut, k] = var.sample(len(mut))
+
+            v = var.sample(len(mut))
+            X[mut, k] = v
 
         return X