[Numpy-discussion] How to apply Numpy ufunc to Scipy sparse matrices?
pav at iki.fi
Sun Sep 11 14:23:45 EDT 2011
Sun, 11 Sep 2011 03:03:26 -0500, Pengkui Luo wrote:
> However, converting a large sparse matrix to dense would easily eat up
> the memory. Is there a way for np.sign (as well as other ufunc) to take
> a sparse matrix as parameter, and return a sparse matrix?
For CSR, CSC, and DIA you can do
x.data = some_ufunc(x.data)
to operate on the nonzero entries. If some_ufunc(0) == 0, that's all you
need. Otherwise, the matrix becomes dense.
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