[Eeglablist] variable times running ICA

[Makoto Miyakoshi]

Dear Baker,

I know that runica() speed variess depending on data quality (AMICA does
not do this). Watch the runica log when you start it and if it says
'lowering learning rate' or something like that, it is 'having hard time
figuring out how to proceed'. If your data is 1) full-rank and 2) clean
(i.e. stationary), it goes fast.

For data rank, see below.
http://sccn.ucsd.edu/wiki/Makoto%27s_preprocessing_pipeline

Makoto

On Tue, Dec 16, 2014 at 7:42 AM, Baker, Joshua <joshua.baker at ntu.ac.uk>
wrote:

> Dear EEGlablist recipients.
>
>
> Could somebody please explain to me the large variation in the time it
> takes to do ICA on datasets of roughly the same size? I am using 64 channel
> Biosemi data at 1024 Hz sampling rate filtered from 0.1 to 500Hz. All
> datasets in this particular experiment are processed using the exact same
> parameters and have the exact same epoch length (1 epoch of 600 seconds).
> Some channels have been omitted from some of the datasets. Some datasets
> take around 20 minutes to run ICA, others take 4 hours and above. What
> could be the reason for this?
>
> Many thanks,
>
> Joshua.
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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