copy over changes made in https://github.com/basnijholt/adaptive-scheduler/blame/master/adaptive_scheduler/sequence_learner.py

Author: basnijholt

adaptive/learner/sequence_learner.py

@@ -1,5 +1,6 @@
-from copy import copy
 import sys
+import warnings
+from copy import copy
 
 from adaptive.learner.base_learner import BaseLearner
 
@@ -11,7 +12,13 @@ def ensure_hashable(x):
         hash(x)
         return x
     except TypeError:
-        return tuple(x)
+        msg = "The items in `sequence` need to be hashable, {}. Make sure you reflect this in your function."
+        if isinstance(x, dict):
+            warnings.warn(msg.format("we converted `dict` to `tuple(dict.items())`"))
+            return tuple(x.items())
+        else:
+            warnings.warn(msg.format("we tried to cast the items to a tuple"))
+            return tuple(x)
 
 
 class SequenceLearner(BaseLearner):
@@ -26,13 +33,11 @@ def __init__(self, function, sequence):
     def ask(self, n, tell_pending=True):
         points = []
         loss_improvements = []
-        i = 0
         for point in self._to_do_seq:
-            if i > n:
+            if len(points) >= n:
                 break
             points.append(point)
             loss_improvements.append(inf / self._npoints)
-            i += 1
 
         if tell_pending:
             for p in points: