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Re: Adding sparse matrices [message #63875]

Fri, 21 November 2008 11:24

Jeremy Bailin
Messages: 618
Registered: April 2008

Senior Member

On Nov 21, 2:03 pm, Paolo <pgri...@gmail.com> wrote:
> Luis wrote:
>> On Nov 21, 4:10 pm, Vince Hradil <vincehra...@gmail.com> wrote:
>> :-) My mail wasn't very detail...
>
>> Unfortunately I can not use c = sprsin(fulstr(a) + fulstr(b)) (Out of
>> memory problems)
>
> Well, it seems that the algorithm is obvious enough:
> if an element is in a and not in b, copy it to c
> if an element is in b and not in a, copy it to c
> if an element is in a and in b, put the sum in c
>
> Ciao,
> Paolo
>
>
>
>>> On Nov 21, 9:59 am, Vince Hradil <vincehra...@gmail.com> wrote:
>
>>>> On Nov 21, 9:27 am, Luis <lgmen...@gmail.com> wrote:
>
>>>> > Hi,
>
>>>> > Does anyone know how to add two sparse matrices?
>
>>>> > Tks,
>>>> > Luis
>
>>>> c = a + b ?
>
>>> Sorry (removing foot from mouth and humbly retreating...)
>
>

The algorithm may be obvious, but reverse-engineering how the indices
are stored in the structure so you can figure out what's what isn't so
obvious (even with a copy of NR). :-)=

-Jeremy.

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[Message index]

		Re: Adding sparse matrices By: Jeremy Bailin on Fri, 21 November 2008 11:24
		Re: Adding sparse matrices By: Jean H. on Fri, 21 November 2008 10:52
		Re: Adding sparse matrices By: pgrigis on Fri, 21 November 2008 11:03
		Re: Adding sparse matrices By: Jeremy Bailin on Fri, 21 November 2008 10:52
		Re: Adding sparse matrices By: colerbe on Fri, 21 November 2008 09:15
		Re: Adding sparse matrices By: David Fanning on Fri, 21 November 2008 08:22
		Re: Adding sparse matrices By: Vince Hradil on Fri, 21 November 2008 08:10
		Re: Adding sparse matrices By: Jeremy Bailin on Fri, 21 November 2008 08:01
		Re: Adding sparse matrices By: Vince Hradil on Fri, 21 November 2008 07:59

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