[GitHub] feevos opened a new issue #9288: Get HybridBlock layer shape on runtime

[GitBox <gi...@apache.org>]

feevos opened a new issue #9288: Get HybridBlock layer shape on runtime
URL: https://github.com/apache/incubator-mxnet/issues/9288
 
 
   Dear all, 
   
   I am trying to build a custom pooling layer (both for ndarray and Symbol) and I need to know the input shape at runtime. According to the documentation, HybridBlock has the function "infer_shape", but I can't make it work. Any pointers into what I am doing wrong?
   
   ## mxnet version
   1.0.0 , build from conda, python3. 
   
   ## Minimum reproducible example
   For example: 
   
   ```Python
   
   import mxnet as mx
   import mxnet.ndarray as nd
   from mxnet.gluon import HybridBlock
   
   class runtime_shape(HybridBlock):
       
      
       def __init__(self,  **kwards):
           HybridBlock.__init__(self,**kwards)
   
   
       def hybrid_forward(self,F,_input):
   
           print (self.infer_shape(_input))
           
           return _input
   
   xx = nd.random_uniform(shape=[5,5,16,16])
   
   mynet = runtime_shape()
   mynet.hybrid_forward(nd,xx)
   
   ```
   
   ## Error Message:
   ```Python
   
   ---------------------------------------------------------------------------
   AttributeError                            Traceback (most recent call last)
   <ipython-input-41-3f539a940958> in <module>()
   ----> 1 mynet.hybrid_forward(nd,xx)
   
   <ipython-input-38-afc9785b716d> in hybrid_forward(self, F, _input)
        17     def hybrid_forward(self,F,_input):
        18 
   ---> 19         print (self.infer_shape(_input))
        20 
        21         return _input
   
   /home/dia021/anaconda2/lib/python2.7/site-packages/mxnet/gluon/block.pyc in infer_shape(self, *args)
       460     def infer_shape(self, *args):
       461         """Infers shape of Parameters from inputs."""
   --> 462         self._infer_attrs('infer_shape', 'shape', *args)
       463 
       464     def infer_type(self, *args):
   
   /home/dia021/anaconda2/lib/python2.7/site-packages/mxnet/gluon/block.pyc in _infer_attrs(self, infer_fn, attr, *args)
       448     def _infer_attrs(self, infer_fn, attr, *args):
       449         """Generic infer attributes."""
   --> 450         inputs, out = self._get_graph(*args)
       451         args, _ = _flatten(args)
       452         arg_attrs, _, aux_attrs = getattr(out, infer_fn)(
   
   /home/dia021/anaconda2/lib/python2.7/site-packages/mxnet/gluon/block.pyc in _get_graph(self, *args)
       369             params = {i: j.var() for i, j in self._reg_params.items()}
       370             with self.name_scope():
   --> 371                 out = self.hybrid_forward(symbol, *grouped_inputs, **params)  # pylint: disable=no-value-for-parameter
       372             out, self._out_format = _flatten(out)
       373 
   
   /home/dia021/anaconda2/lib/python2.7/site-packages/mxnet/gluon/block.pyc in __exit__(self, ptype, value, trace)
        78         if self._block._empty_prefix:
        79             return
   ---> 80         self._name_scope.__exit__(ptype, value, trace)
        81         self._name_scope = None
        82         _BlockScope._current = self._old_scope
   
   AttributeError: 'NoneType' object has no attribute '__exit__'
   
   ```
   
   

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