[Eeglablist] Huge speedup in runica

[Makoto Miyakoshi]

> During the conference on Tuesday someone wrote:

The name of this amazing hacker is Tjerk Gutteling.

Makoto


On Thu, Jun 17, 2021 at 5:33 PM Curtis Bingham <cnbingham at gmail.com> wrote:

> During the conference on Tuesday someone wrote:
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> “Just something that I found in the runica() script: if you comment out
> "drawnow" on line 1047, there is a dramatic speed-up of the script. This
> has something to do with the GUI and nothing with ICA itself, so I think it
> could easily be optimized.”
>
> Arnaud created an issue in github for runica.m.
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> Replacing ‘drawnow’ with ‘drawnow limitrate’ cuts the processing time in
> my trials from ~400 seconds to 55-64 seconds. I’m processing 19 channel
> data, 10 minutes in length, no ERPs. I’m sure the gains will be even more
> significant with additional channels and especially with multiple data sets
> within a STUDY.
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> The drawnow function is called in 6 different places in repeating loops.
> It is designed to allow gui refresh and callbacks to be executed when
> running within the gui.  Commenting it out removes all interactivity with
> Matlab or EEGLab while running an extended ICA decomposition.
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> If you append ‘limitrate’ to the command, it only refreshes the gui every
> 20fps instead of every time the function is called. If less than 50ms have
> elapsed since the last call it tosses graphics updates but executes
> callbacks. Very good interactivity is retained, as is the ability to
> interrupt the ICA decomposition.
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> Merely commenting out the drawnow doesn’t materially change the execution
> time on my data. However, as a matter of good coding practice this should
> be turned off altogether if not running inside a GUI.
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> I recommend that, at the very least, runica.m be modified to replace
> ‘drawnow’ with ‘drawnow limitrate’.
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> Curtis
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