Added optional broadcastable argument to shared variable constructor for

theano/compile/sandbox/sharedvalue.py

@@ -138,13 +138,14 @@ def generic_constructor(value, name=None, strict=False):
 class TensorSharedVariable(SharedVariable, theano.tensor.basic._tensor_py_operators):
     pass
 @shared_constructor
-def tensor_constructor(value, name=None, strict=False):
+def tensor_constructor(value, name=None, strict=False, broadcastable=None):
     """SharedVariable Constructor for TensorType"""
     if not isinstance(value, numpy.ndarray):
         raise TypeError()
 
-    bcast = [b==1 for b in value.shape]
-    type = TensorType(value.dtype, broadcastable=bcast)
+    if broadcastable is None:
+        broadcastable = [b==1 for b in value.shape]
+    type = TensorType(value.dtype, broadcastable=broadcastable)
     return TensorSharedVariable(type=type, value=value, name=name, strict=strict)
 
 @shared_constructor