Minor modifications

AtalsKim · Mar 4, 2019 · 7412348 · 7412348
1 parent be6987a
commit 7412348
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Showing 3 changed files with 17 additions and 7 deletions.
diff --git a/pymoo/algorithms/so_de.py b/pymoo/algorithms/so_de.py
@@ -13,9 +13,10 @@
 
 class DifferentialEvolution(GeneticAlgorithm):
     def __init__(self,
-                 variant="DE/rand+best/1/exp",
+                 variant="DE/rand+best/1/bin",
                  CR=0.5,
                  F=0.75,
+                 n_replace=None,
                  **kwargs):
 
         _, self.var_selection, self.var_n, self.var_mutation, = variant.split("/")
@@ -28,6 +29,7 @@ def __init__(self,
         set_if_none(kwargs, 'survival', None)
         super().__init__(**kwargs)
 
+        self.n_replace = n_replace
         self.func_display_attrs = disp_single_objective
 
     def _next(self, pop):
@@ -75,8 +77,14 @@ def _next(self, pop):
         _F, _CV, _feasible = self.off.get("F", "CV", "feasible")
         _F = parameter_less(_F, _CV)
 
-        # replace if better
-        is_better = (_F <= F)[:, 0]
+        # find the individuals which are indeed better
+        is_better = np.where((_F <= F)[:, 0])[0]
+
+        # truncate the replacements if desired
+        if self.n_replace is not None and self.n_replace < len(is_better):
+            is_better = is_better[random.perm(len(is_better))[:self.n_replace]]
+
+        # replace the individuals in the population
         pop[is_better] = self.off[is_better]
 
         return pop
diff --git a/pymoo/indicators/igd.py b/pymoo/indicators/igd.py
@@ -21,10 +21,8 @@ def dist(A, B):
                 return np.sqrt(np.sum(np.square((A - B) / self.N), axis=1))
 
             D = vectorized_cdist(self.pareto_front, F, dist)
-            #_D = cdist(self.pareto_front, F, metric=lambda u, v: np.sqrt((((u - v)/self.N) ** 2).sum()))
+
         else:
             D = cdist(self.pareto_front, F)
 
-        #np.all(np.abs(cdist(self.pareto_front, F) - D) < 1e-4)
-
         return np.mean(np.min(D, axis=1))
diff --git a/pymoo/usage/de.py b/pymoo/usage/de.py
@@ -6,7 +6,11 @@
 res = minimize(problem,
                method='de',
                method_args={
-                   'pop_size': 100
+                   'variant': "DE/best/1/bin",
+                   'CR': 2,
+                   'F': 0.75,
+                   'n_replace': 5,
+                   'pop_size': 200
                },
                termination=('n_gen', 1000),
                disp=True)