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Re: adding sparse arrays [message #54301 is a reply to message #54300]

Thu, 07 June 2007 07:32

nivedita.raghunath
Messages: 15
Registered: July 2006

Junior Member

Hi all,

Thanks for the suggestions.

The arrays that I'm working with are really huge so there's no option
of A+B. I cannot convert to full matrix form using fulstr and have to
work only with the sparse arrays A and B to get another sparse array (A
+B). The non-zero elements of the two arrays are in different index
positions (ija), so the sa vectors cannot be added directly.

Under these constraints, whats the best (and the fastest) way to add
them?

-Nivedita

On Jun 7, 4:36 am, Paolo Grigis <pgri...@astro.phys.ethz.ch> wrote:
> nivedita.raghun...@gmail.com wrote:
>> Hello all,
>
>> How do I add two sparse arrays? The fact that a sparse function to add
>> doesn't exist makes me think its pretty simple, but I just can't get
>> it. I do not want to use any loops.
>
> Well, it depends where the non-zero, non-diagonal elements of the two
> arrays are. If they are located in the same positions, you just need
> to add the sa vectors while keeping the ija vectors fixed.
>
> Ciao,
> Paolo
>
>
>
>
>
>> Thanks in advance.
>
>> -Nivedita- Hide quoted text -
>
> - Show quoted text -

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[Message index]

		Re: adding sparse arrays By: nivedita.raghunath on Thu, 07 June 2007 11:13
		Re: adding sparse arrays By: nivedita.raghunath on Thu, 07 June 2007 10:50
		Re: adding sparse arrays By: Vince Hradil on Thu, 07 June 2007 08:23
		Re: adding sparse arrays By: nivedita.raghunath on Thu, 07 June 2007 07:32
		Re: adding sparse arrays By: Paolo Grigis on Thu, 07 June 2007 01:36
		Re: adding sparse arrays By: Gaurav on Thu, 07 June 2007 00:30
		Re: adding sparse arrays By: zhang.yuji on Wed, 06 June 2007 21:29
		Re: adding sparse arrays By: Paolo Grigis on Fri, 08 June 2007 00:42

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