Make broadcast fixup in filter_variable() depend on an argument and stop doing…

theano/compile/pfunc.py

@@ -101,7 +101,8 @@ def rebuild_collect_shared(outputs,
                     # Do not use default_update if a "real" update was
                     # provided
                     if v not in update_d:
-                        v_update = v.type.filter_variable(v.default_update)
+                        v_update = v.type.filter_variable(v.default_update,
+                                                          allow_convert=False)
                         if v_update.type != v.type:
                             raise TypeError(
                                 'an update must have the same type as '
@@ -197,7 +198,8 @@ def rebuild_collect_shared(outputs,
 
         # filter_variable ensure smooth conversion of cpu/gpu Types
         try:
-            update_val = store_into.type.filter_variable(update_val)
+            update_val = store_into.type.filter_variable(update_val,
+                                                         allow_convert=False)
         except TypeError:
             err_msg = ('An update must have the same type as the'
                        ' original shared variable (shared_var=%s,'

theano/gof/null_type.py

@@ -21,7 +21,7 @@ class NullType(Type):
     def filter(self, data, strict=False, allow_downcast=None):
         raise ValueError("No values may be assigned to a NullType")
 
-    def filter_variable(self, other):
+    def filter_variable(self, other, allow_convert=True):
         raise ValueError("No values may be assigned to a NullType")
 
     def may_share_memory(a, b):

theano/gof/type.py

@@ -263,7 +263,7 @@ class PureType(object):
 
     # def filter_inplace(value, storage, strict=False, allow_downcast=None)
 
-    def filter_variable(self, other):
+    def filter_variable(self, other, allow_convert=True):
         """Convert a symbolic variable into this Type, if compatible.
 
         For the moment, the only Types compatible with one another are
@@ -277,7 +277,7 @@ class PureType(object):
             # a Constant of the appropriate Type.
             other = self.Constant(type=self, data=other)
 
-        if other.type != self:
+        if other.type != self and allow_convert:
             other2 = self.convert_variable(other)
             if other2 is not None:
                 return other2
@@ -290,6 +290,24 @@ class PureType(object):
                 % dict(othertype=other.type, other=other, self=self))
         return other
 
+    def convert_variable(self, var):
+        """Patch variable so that its type will match self, if possible.
+
+        If the variable can't be converted, this should return None.
+
+        The conversion can only happen if the following implication is
+        true for all possible `val`.
+
+          self.is_valid_value(val) => var.type.is_valid_value(val)
+
+        For the majority of types this means that you can only have
+        non-broadcastable dimensions become broadcastable and not the
+        inverse.
+
+        The default is to not convert anything which is always safe.
+        """
+        return None
+
     def is_valid_value(self, a):
         """Required: Return True for any python object `a` that would be a
 legal value for a Variable of this Type"""
@@ -409,23 +427,6 @@ class Type(object2, PureType, CLinkerType):
     do type-checking in pattern-based optimizations.
 
     """
-    def convert_variable(self, var):
-        """Patch variable so that its type will match self, if possible.
-
-        If the variable can't be converted, this should return None.
-
-        The conversion can only happen if the following implication is
-        true for all possible `val`.
-
-          self.is_valid_value(val) => var.type.is_valid_value(val)
-
-        For the majority of types this means that you can only have
-        non-broadcastable dimensions become broadcastable and not the
-        inverse.
-
-        The default is to not convert anything which is always safe.
-        """
-        return None
 
 
 class SingletonType(Type):

theano/sandbox/cuda/type.py

@@ -119,7 +119,7 @@ class CudaNdarrayType(Type):
                         % (self, self.dtype, data, converted_data, self.dtype),
                         data)
 
-    def filter_variable(self, other):
+    def filter_variable(self, other, allow_convert=True):
         """Convert a Variable into a CudaNdarrayType, if compatible.
 
         This Variable should either already be a CudaNdarrayType, or be
@@ -146,8 +146,11 @@ class CudaNdarrayType(Type):
             raise TypeError('Incompatible number of dimensions.'
                             ' Expected %d, got %d.' % (self.ndim, other.ndim))
         if other.type.broadcastable != self.broadcastable:
-            type2 = other.type.clone(broadcastable=self.broadcastable)
-            other2 = type2.convert_variable(other)
+            if allow_convert:
+                type2 = other.type.clone(broadcastable=self.broadcastable)
+                other2 = type2.convert_variable(other)
+            else:
+                other2 = None
             if other2 is None:
                 raise TypeError('Incompatible broadcastable dimensions.'
                                 ' Expected %s, got %s.' %

theano/sandbox/gpuarray/type.py

@@ -89,7 +89,7 @@ class GpuArrayType(Type):
                                 " dimension.", shp, self.broadcastable)
         return data
 
-    def filter_variable(self, other):
+    def filter_variable(self, other, allow_convert=True):
         if hasattr(other, '_as_GpuArrayVariable'):
             other = other._as_GpuArrayVariable()
 
@@ -108,8 +108,11 @@ class GpuArrayType(Type):
             raise TypeError('Incompatible number of dimensions.'
                             ' Expected %d, got %d.' % (self.ndim, other.ndim))
         if other.type.broadcastable != self.broadcastable:
-            type2 = other.type.clone(broadcastable=self.broadcastable)
-            other2 = type2.convert_variable(other)
+            if allow_convert:
+                type2 = other.type.clone(broadcastable=self.broadcastable)
+                other2 = type2.convert_variable(other)
+            else:
+                other2 = None
             if other2 is None:
                 raise TypeError('Incompatible broadcastable dimensions.'
                                 ' Expected %s, got %s.' %

theano/tensor/type.py

@@ -190,7 +190,7 @@ class TensorType(Type):
             raise ValueError("non-finite elements not allowed")
         return data
 
-    def filter_variable(self, other):
+    def filter_variable(self, other, allow_convert=True):
         """Convert a symbolic Variable into a TensorType, if compatible.
 
         For the moment, only a TensorType or CudaNdarrayType will be
@@ -208,10 +208,11 @@ class TensorType(Type):
         if other.type == self:
             return other
 
-        # Attempt safe broadcast conversion.
-        other2 = self.convert_variable(other)
-        if other2 is not None and other2.type == self:
-            return other2
+        if allow_convert:
+            # Attempt safe broadcast conversion.
+            other2 = self.convert_variable(other)
+            if other2 is not None and other2.type == self:
+                return other2
 
         raise TypeError(
             'Cannot convert Type %(othertype)s '