Re: deprecated functions

[Jaroslav Hajek]

On Wed, Mar 4, 2009 at 8:59 PM, John W. Eaton <address@hidden> wrote:
> On  4-Mar-2009, Jaroslav Hajek wrote:
>
> | I agree it would be more useful, as they really are special kind of
> | sparse matrices.
> | But it would break backward and Matlab compatibility in a fairly
> | invasive way (infinitely more than the recently discussed NaN issues),
> | so I think a wide agreement is really necessary here.
>
> OK, if we don't make diag x sparse matrices retain the sparsity, then
> what method do we have that allows row or column scaling of a sparse
> matrix (for example) which preserves sparsity?  The modified version
> of dmult did that, correct?  I think that's what Jason was complaining
> about (correct me if I'm wrong).
>

diag(sparse(vector)) * sparse matrix,
obviously. It will be less efficient than with dense matrices, but will work.
I believe the sparse scaling of dmult was an unintended side effect,
because constructing a temporary dense matrix of the same size is
certainly a *very* inefficient way to do the scaling.

If dmult is to be brought back, then I will reimplement it to wrap
either diag(A)*B or diag(sparse(A))*B.
It just seems to me these expressions are more transparent, and also
matlab compatible.
Maybe we can update the deprecation comment for dmult.

cheers

-- 
RNDr. Jaroslav Hajek
computing expert & GNU Octave developer
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz