Fixed infer_shape.

doc/tutorial/extending_theano.txt

@@ -471,29 +471,16 @@ Op Example
     from theano.compile.ops import as_op
     from theano.compile.ops import FromFunctionOp
 
+    def infer_shape_numpy_dot(node, input_shapes):
+        ashp, bshp = input_shapes
+        return [ashp[:-1] + bshp[-1:]]
+
     @as_op(itypes=[theano.tensor.fmatrix, theano.tensor.fmatrix],
-          otypes=[theano.tensor.fmatrix])
+          otypes=[theano.tensor.fmatrix], infer_shape=infer_shape_numpy_dot)
+
     def numpy_dot(a, b):
        return numpy.dot(a, b)
 
-        def infer_shape(self, node, shapes):
-            xshp, yshp = shapes
-            x, y = node.inputs
-
-            # vector / vector
-            if x.ndim == 1 and y.ndim == 1:
-                return [()]
-            # matrix / vector
-            if x.ndim == 2 and y.ndim == 1:
-                return [xshp[:-1]]
-            # vector / matrix
-            if x.ndim == 1 and y.ndim == 2:
-                return [yshp[-1:]]
-            # matrix / matrix
-            if x.ndim == 2 and y.ndim == 2:
-                return [xshp[:-1] + yshp[-1:]]
-            raise NotImplementedError()
-
 You can try it as follows:
 
 .. code-block:: python