Add infer_shape to MinibatchRandomVariable

Author: ricardoV94

pymc/variational/minibatch_rv.py

@@ -40,6 +40,9 @@ def make_node(self, rv, *total_size):
         out = rv.type()
         return Apply(self, [rv, *total_size], [out])
 
+    def infer_shape(self, fgraph, node, shapes):
+        return [shapes[0]]
+
     def perform(self, node, inputs, output_storage):
         output_storage[0][0] = inputs[0]