ok , i don't think, i can explain this problem in words so , here is the snippet of ipython session , where i import scipy , in order to construct a sparse matrix.
In [1]: import scipy as sp
In [2]: a = sp.sparse.lil_matrix((5,5))
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
/home/liveuser/<ipython-input-2-b5a55fc2d0ac> in <module>()
----> 1 a = sp.sparse.lil_matrix((5,5))
AttributeError: 'module' object has no attribute 'sparse'
In [3]: import scipy.sparse as spar
In [4]: ax = spar.lil_matrix((5,5))
In [5]: a = sp.sparse.lil_matrix((5,5)) # you are kidding me?
In [6]: a
Out[6]:
<5x5 sparse matrix of type '<type 'numpy.float64'>'
with 0 stored elements in LInked List format>
In [7]: ax
Out[7]:
<5x5 sparse matrix of type '<type 'numpy.float64'>'
with 0 stored elements in LInked List format>
what is happening there , why can't construct a sparse matrix using sp , in the first time , when i import sparse sub-module in a particular way (as in snippet) , both sp and spar variables can now be used to construct sparse matrices.(i guess they are just references to same object)
I reproduced this python default shell , (so it is not ipython specific)
what's going on , is it by design?? if so kindly elaborate. or is it a bug??
My system is Fedora 16 KDE-scientific,64 bit.
This is an artifact of Python's importing, not of SciPy. Do
from scipy import sparse [as sp]
or
import scipy.sparse [as sp]
(where [] is meta-notation for optionality).
In short, the import statement needs to know the module's "true" name, not some abbreviation created by an import as statement.