Re: compound operators - what next?

[dbateman]

Jaroslav Hajek-2 wrote:
> 
> Other possibility is to flag even dense matrix with MatrixType
> "diagonal" and make diag and eye return such a matrix; in such case,
> diag(v)*A would be time-efficient but not memory-efficient (because
> the matrix would still get constructed).
> 

Ok for the flag coming from diag but not that diagonal matrices are probed



>>
>> This would pretty much implement the third option with little work and
>> only
>> require the user to use sparse diagonal matrices instead for the scaling.
>> Its also not using tricks in the parser to get the wanted behavior and so
>> can't be fooled by d=diag(v);d*A as your other technique will be.
>>
> 
> exactly, exactly ...
> I hope I did not misunderstood you; it seems to me that you are OK
> with diag and eye
> returning sparse matrices, right?
> 

I said diags and not diag, but I meant spdiags. I don't thinks its a great
idea to have eye and diag return sparse matrices. Rather that the the
acceleration you are after might already be there or easy to achieve if the
user replaced diag with spdiags.

D.


-- 
View this message in context: 
http://www.nabble.com/compound-operators---what-next--tp17311996p17328261.html
Sent from the Octave - Maintainers mailing list archive at Nabble.com.