Merge pull request #5163 from nouiz/constant_folding

theano/compile/function_module.py

@@ -794,9 +794,16 @@ class Function(object):
                             function_name += ' with name "' + self.name + '"'
                         if hasattr(arg, 'name') and arg.name:
                             argument_name += ' with name "' + arg.name + '"'
-                        e.args = ("Bad input " + argument_name + " to " +
-                                  function_name + " at index %d (0-based)"
-                                  % i,) + e.args
+                        where = theano.gof.utils.get_variable_trace_string(
+                            self.maker.inputs[i].variable)
+                        if len(e.args) == 1:
+                            e.args = ("Bad input " + argument_name + " to " +
+                                      function_name + " at index %d (0-based). %s"
+                                      % (i, where) + e.args[0],)
+                        else:
+                            e.args = ("Bad input " + argument_name + " to " +
+                                      function_name + " at index %d (0-based). %s"
+                                      % (i, where),) + e.args
                         raise
                 s.provided += 1
                 i += 1

theano/tensor/elemwise.py

@@ -1277,7 +1277,8 @@ second dimension
         Return True if we do not want to compile c code
         when doing constant folding of this node.
         """
-        return node.outputs[0].ndim == 0
+        # The python code don't support 32 inputs or more.
+        return node.outputs[0].ndim == 0 and len(node.inputs) < 32
 
 
 ################

theano/tensor/type.py

@@ -135,9 +135,9 @@ class TensorType(Type):
                             'this loss, you can: '
                             '1) explicitly cast your data to %s, or '
                             '2) set "allow_input_downcast=True" when calling '
-                            '"function".'
-                            % (self, data.dtype, self.dtype))
-                        raise TypeError(err_msg, data)
+                            '"function". Value: "%s"'
+                            % (self, data.dtype, self.dtype, repr(data)))
+                        raise TypeError(err_msg)
                 elif (allow_downcast is None and
                         type(data) is float and
                         self.dtype == theano.config.floatX):