Re: [Icatb-discuss] Error message from Group ICA on large dataset

[Srinivas R. <sra...@mr...>]

Hi Bruce,

Probably the data might be filtered or less number of degrees of freedom in
the data than the number of components selected. Try reducing the number of
components.

Thanks,
Srinivas

On Wed, Nov 5, 2014 at 10:08 AM, J Bruce Morton <jbr...@gm...>
wrote:

> Dear Gift users,
>
>
> Am attempting to run a group ICA on a large data set (250 participants/3
> runs per participant).
>
>
> I have a few questions:
>
>
> (1) In in the interest of keeping RAM demands to within 40GB, I have
> selected Expectation Maximization for the PCA type (w single precision, and
> 1000 max iterations).
>
> I get the following error. I am wondering whether this is a problem data
> set or something to do with the way I parametrized the PCA? If the latter,
> what is the recommended parameterization of the PCA?
>
>
> ......................................
>
> Group ICA Error Information:
>
>
> Error using ==> icatb_dataReduction>checkEig at 1110
>
> One of the eigen values is less than or equal to machine precision
>
>
> Error in ==> <a
>
> href="matlab:opentoline('/home/mortonjb/GroupICATv3.0a/icatb/icatb_analysis_functions/icatb_dataReduction.m',
> 1110)">checkEig at 1110</a>
>
> Error in ==> <a
>
> href="matlab:opentoline('/home/mortonjb/GroupICATv3.0a/icatb/icatb_analysis_functions/icatb_dataReduction.m',
> 818)">icatb_dataReduction at 818</a>
>
> Error in ==> <a
>
> href="matlab:opentoline('/home/mortonjb/GroupICATv3.0a/icatb/icatb_analysis_functions/icatb_runAnalysis.m',
> 366)">icatb_runAnalysis at 366</a>
>
> Error in ==> <a
>
> href="matlab:opentoline('/home/mortonjb/dynamic_networks/Scripts/DN_run_ica.m',
> 13)">DN_run_ica at 13</a>
>
> ......................................
>
>
> --
> Dr J Bruce Morton, PhD
> Associate Professor
> Cognitive Development and Neuroimaging Laboratory
> Department of Psychology
> Brain and Mind Institute
> Westminster Hall, 324
> University of Western Ontario
> London, Ontario
> CANADA
> N6A 3K7
>
> TEL: 519-661-2111 x84795
> FAX: 519-850-2554
>
> http://www.uwo.ca/neuroscience/
> http://www.uwo.ca/its/brain/
> http://www.cdnlwestern.ca
>
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