feats: polish rnnbase

python/jittor/nn.py

@@ -11,6 +11,7 @@
 # This file is subject to the terms and conditions defined in
 # file 'LICENSE.txt', which is part of this source code package.
 # ***************************************************************
+from abc import abstractmethod
 import jittor as jt
 from jittor import init, Module
 import numpy as np
@@ -1537,6 +1538,10 @@ class RNNBase(Module):
                 build_unit(f'bias_ih_l{layer}', gate_size)
                 build_unit(f'bias_hh_l{layer}', gate_size)
 
+    @abstractmethod
+    def call_rnn_cell(self, input, hidden, suffix):
+        pass
+
     def call_rnn_sequence(self, input, hidden, suffix):
         if 'reverse' in suffix:
             input = input[::-1]