[GitHub] mseth10 opened a new issue #14105: nd.slice errors out when end=-1 and step=-1

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

mseth10 opened a new issue #14105: nd.slice errors out when end=-1 and step=-1
URL: https://github.com/apache/incubator-mxnet/issues/14105
 
 
   ### Description
   For `mxnet.ndarray.slice(data, begin, end)`, if `end=-1` and `step=-1`, it does not return a reversed tensor. Instead, it gives an invalid data error.
   
   ### Minimum reproducible environment
   ```
   >>> import mxnet.ndarray as nd
   >>> a = nd.normal(shape=(4))
   >>> a
   [2.2122064 0.7740038 1.0434405 1.1839255]
   <NDArray 4 @cpu(0)>a = nd.normal(shape=(4))
   >>> a1 = nd.slice(a, begin=2, end=-1, step=-1)
   ```
   Expected output: `[1.0434405 0.7740038 2.2122064]`
   Outputs:
   ```
   Traceback (most recent call last):
     File "test_slice.py", line 4, in <module>
       a1 = nd.slice(a, begin=2, end=-1, step=-1)
     File "<string>", line 86, in slice
     File "/home/ubuntu/workspace/mxnet0/python/mxnet/_ctypes/ndarray.py", line 92, in _imperative_invoke
       ctypes.byref(out_stypes)))
     File "/home/ubuntu/workspace/mxnet0/python/mxnet/base.py", line 252, in check_call
       raise MXNetError(py_str(_LIB.MXGetLastError()))
   mxnet.base.MXNetError: [13:57:39] /home/ubuntu/workspace/mxnet0/src/operator/tensor/./matrix_op-inl.h:716: Check failed: e < b (3 vs. 2) slicing with begin=[0]=2, end[0]=3, and step[0]=-1 is invalid
   ```
   ```

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