[GitHub] ZiyueHuang commented on issue #8259: [WIP] check_format of ndrray, mainly for csr

[gi...@git.apache.org]

ZiyueHuang commented on issue #8259: [WIP] check_format of ndrray, mainly for csr
URL: https://github.com/apache/incubator-mxnet/pull/8259#issuecomment-336613288
 
 
   Seems that scipy will not check the validity for computations like `sqrt` or `transpose`, but will check for methods like `toarray`.  scipy has `scipy.sparse.csr_matrix.check_format`.
   ```python
   >>> import scipy.sparse as spsp
   >>> a = spsp.csr_matrix(([0],[10],[0,1]), shape=(1,2))
   >>> a.sqrt()
   <1x2 sparse matrix of type '<type 'numpy.float64'>'
   	with 1 stored elements in Compressed Sparse Row format>
   >>> a.toarray()
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
     File "/usr/lib/python2.7/dist-packages/scipy/sparse/compressed.py", line 940, in toarray
       return self.tocoo(copy=False).toarray(order=order, out=out)
     File "/usr/lib/python2.7/dist-packages/scipy/sparse/compressed.py", line 936, in tocoo
       return coo_matrix((data,(row,col)), self.shape)
     File "/usr/lib/python2.7/dist-packages/scipy/sparse/coo.py", line 182, in __init__
       self._check()
     File "/usr/lib/python2.7/dist-packages/scipy/sparse/coo.py", line 238, in _check
       raise ValueError('column index exceeds matrix dimensions')
   ValueError: column index exceeds matrix dimensions
   >>> a.check_format()
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
     File "/usr/lib/python2.7/dist-packages/scipy/sparse/compressed.py", line 177, in check_format
       (minor_name,minor_dim))
   ValueError: column index values must be < 2
   >>> a.transpose()
   <2x1 sparse matrix of type '<type 'numpy.int64'>'
   	with 1 stored elements in Compressed Sparse Column format>
   ```
   
 
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