Re: [igraph] Feedback on network animation code?

[Gábor Csárdi]

On Thu, Nov 29, 2012 at 10:52 AM, Jeff Hemsley <address@hidden> wrote:

[...]

The area of code that I'm actually interested in making more efficient
is where I am fading out the colors of links/vertex because it is a
loop in a loop and I was hoping there was a way to vectorize it.

You can replace the inner loop with something like this:

alpha.vec.idx <- match(E(g)$date, possible.dates) - date.fade.index[1] + 1

alpha.vec.idx <- ifelse(alpha.vec.idx < 1 | alpha.vec.idx > length(alpha.vec),

                        1, alpha.vec.idx)

E(g)$alpha <- alpha.vec[alpha.vec.idx]

V(g)$alpha <- sapply(V(g), function(v) { max(E(g)$alpha[incident(g, v)]) })

It requires that the first element in alpha.vec is zero.

This is still a loop, though, because of the sapply, but I believe that it is faster. Actually I would think that the bottleneck is exporting the PNG files, but I might be wrong....

Gabor

 

The reason I ask is because these networks are small, but I have far
larger ones I'd like to automate.

Thoughts on that?

On Thu, Nov 29, 2012 at 7:05 AM, Gábor Csárdi <address@hidden> wrote:
> Hi Jeff, I think it looks great!
>
> What exactly do you want to improve on the code? It all looks very
> reasonable for me, so unless you desire another feature or the code is slow,
> why change it? Do not change code that does everything you want. :)
>
> Btw. the igraph wiki turned out to be not very efficient to share igraph
> related code snipplets, so maybe we will start a blog that aggregates them,
> or move to gists at github. I want to put code like yours on the igraph
> homepage somehow.
>
> Best
> Gabor
>
>
> On Wed, Nov 28, 2012 at 3:53 PM, Jeff Hemsley <address@hidden>
> wrote:
>>
>> I'm somewhat new to iGraph, and pretty good at R, but I am still
>> learning. I found a way to animate an evolving network with iGraph in
>> R and would love to get any feedback on how to improve the code.
>>
>> The code, well commented, is here:
>>
>>
>> http://somelab.net/2012/11/how-to-create-a-network-animation-with-r-and-the-igraph-package/
>>
>> Any feedback, suggestions, comments are welcome.
>> Thanks!
>>
>> --
>> Jeff Hemsley
>> Doctoral Student
>> The iSchool
>> University of Washington
>> http://ischool.uw.edu/
>> address@hidden
>>
>> _______________________________________________
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>> address@hidden
>> https://lists.nongnu.org/mailman/listinfo/igraph-help
>
>
>
>
> --
> Gabor Csardi <address@hidden>     MTA KFKI RMKI
>
>
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--

Jeff Hemsley
Doctoral Candidate
The Information School

University of Washington
http://ischool.uw.edu/
address@hidden

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Gabor Csardi <address@hidden>     MTA KFKI RMKI