small edits to SympyCCode and test

theano/scalar/basic_sympy.py

@@ -88,7 +88,7 @@ class SymPyCCode(ScalarOp):
     def grad(self, inputs, output_grads):
         return [SymPyCCode(self.inputs,
                            self.expr.diff(inp),
-                           name=self.name+"_prime_%d"%i)(*inputs)
+                           name=self.name+"_grad_%d"%i)(*inputs)
                 for i, inp in enumerate(self.inputs)]
 
     def _info(self):

theano/scalar/tests/test_basic_sympy.py

@@ -26,8 +26,8 @@ def test_grad():
     assert ztprime.owner.op.expr == 2*xs
 
 def test_multivar_grad():
-    op = SymPyCCode([xs, ys], xs**2 + ys**2)
+    op = SymPyCCode([xs, ys], xs**2 + ys**3)
     zt = op(xt, yt)
     dzdx, dzdy = theano.grad(zt, [xt, yt])
     assert dzdx.owner.op.expr == 2*xs
-    assert dzdy.owner.op.expr == 2*ys
+    assert dzdy.owner.op.expr == 3*ys**2