Merge pull request #961 from rizar/better_error_for_duplicate_names

Better error message and test for duplicate names

blocks/monitoring/evaluators.py

@@ -114,7 +114,12 @@ def __init__(self, variables, use_take_last=False):
 
         self.variable_names = [v.name for v in self.variables]
         if len(set(self.variable_names)) < len(self.variables):
-            raise ValueError("variables should have different names")
+            duplicates = []
+            for vname in set(self.variable_names):
+                if self.variable_names.count(vname) > 1:
+                    duplicates.append(vname)
+            raise ValueError("variables should have different names!"
+                             " Duplicates: {}".format(', '.join(duplicates)))
         self._computation_graph = ComputationGraph(self.variables)
         self.inputs = self._computation_graph.inputs
 

tests/monitoring/test_aggregation.py

@@ -1,6 +1,6 @@
 import numpy
 import theano
-from numpy.testing import assert_allclose
+from numpy.testing import assert_allclose, assert_raises
 from theano import tensor
 
 from blocks import bricks
@@ -14,7 +14,7 @@
 from fuel.streams import DataStream
 from fuel.schemes import SequentialScheme
 
-from blocks.monitoring.evaluators import DatasetEvaluator
+from blocks.monitoring.evaluators import DatasetEvaluator, AggregationBuffer
 
 
 class TestBrick(bricks.Brick):
@@ -89,3 +89,9 @@ def test_mean_aggregator():
                     numpy.array([8.25, 26.75], dtype=theano.config.floatX))
     assert_allclose(DatasetEvaluator([z]).evaluate(data_stream)['z'],
                     numpy.array([35], dtype=theano.config.floatX))
+
+
+def test_aggregation_buffer():
+    x1 = tensor.matrix('x')
+    x2 = tensor.matrix('x')
+    assert_raises(ValueError, AggregationBuffer, [x1, x2])