fixed bug where tensor.grad could try to add DisconnectedType to other

theano/gradient.py

@@ -681,6 +681,10 @@ def _populate_grad_dict(var_to_node_to_idx,
                                 "encountered a NaN. " +\
                                     term.type.why_null)
 
+                        #Don't try to sum up DisconnectedType placeholders
+                        if isinstance(term.type, DisconnectedType):
+                            continue
+
                         terms.append(term)
                 #the next line is like sum(terms) but doesn't add an
                 #extraneous TensorConstant(0)

theano/scalar/basic.py

@@ -332,7 +332,7 @@ class Scalar(Type):
                 return '''
                 template <> %(mytype)s & %(mytype)s::operator=<%(othertype)s>(const %(othertype)s & y)
                 { this->real=y; this->imag=0; return *this; }
-                ''' % dict(mytype = mytype, othertype = othertype)
+                ''' % dict(mytype=mytype, othertype=othertype)
 
             def operator_eq_cplx(mytype, othertype):
                 return '''