added another sort in create_subbasis also for deterministic purposes

Author: juangmendoza19

pygsti/baseobjs/errorgenbasis.py

@@ -232,6 +232,7 @@ def overlaps(sslbls):
             sub_labels, sub_indices = zip(*[(lbl, i) for i, lbl in enumerate(self._labels)
                                             if overlaps(lbl[0])])
             sub_state_space = self.state_space.create_subspace(sub_sslbls)
+            sub_sslbls = sorted(sub_sslbls)
         else:
             sub_labels = []
             for lbl in self.labels: