fix lstm layer with projection save params (#17266)

python/mxnet/gluon/rnn/rnn_layer.py

@@ -124,7 +124,7 @@ def __repr__(self):
     def _collect_params_with_prefix(self, prefix=''):
         if prefix:
             prefix += '.'
-        pattern = re.compile(r'(l|r)(\d)_(i2h|h2h)_(weight|bias)\Z')
+        pattern = re.compile(r'(l|r)(\d)_(i2h|h2h|h2r)_(weight|bias)\Z')
         def convert_key(m, bidirectional): # for compatibility with old parameter format
             d, l, g, t = [m.group(i) for i in range(1, 5)]
             if bidirectional:

tests/python/gpu/test_gluon_gpu.py

@@ -137,6 +137,8 @@ def test_lstmp():
     check_rnn_layer_forward(gluon.rnn.LSTM(10, 2, bidirectional=True, dropout=0.5, projection_size=5),
                             mx.nd.ones((8, 3, 20)),
                             [mx.nd.ones((4, 3, 5)), mx.nd.ones((4, 3, 10))], run_only=True, ctx=ctx)
+    lstm_layer.save_parameters('gpu_tmp.params')
+    lstm_layer.load_parameters('gpu_tmp.params')
 
 
 @with_seed()