[SciPy-dev] sparsetools - new and (hopefully) improved!
cimrman3 at ntc.zcu.cz
Fri Jan 5 04:44:10 CST 2007
Nathan Bell wrote:
> On 1/4/07, Robert Cimrman <cimrman3 at ntc.zcu.cz> wrote:
>> Hi Nathan, I have not had time to look at your code yet (just returned
>> from holidays) but the description looks great!
>> One umfpack-related note - the solver requires the CSC/CSR column/row
>> indices sorted in ascending order. Does your implementation contain a
>> function to ensure_sorted_indices()?
> Not currently, but it would be trivial to add. Converting from
> CSR<->CSC (a linear time operation) has the side effect of sorting the
> column/row indices. Two conversions (CSR->CSC->CSR) would produce the
> desired result in the original format.
> I will add ensure_sorted_indices() to csr_matrix and csc_matrix.
Good! Going CSR->CSC->CSR would be too inefficient, IMHO. Maybe we could
add a flag to the CSR/CSC matrix class saying that it has sorted indices
to make the check trivial. It should be added as keyword argument to the
matrix constructor, too.
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