[Eeglablist] AMICA error on 256 channels EEG

[liao ke]

Hi Jason,

Thank you for your reply!

Here are the minimum eigenvalues in the out.txt file of a 256-channel EEG
dataset with AMICA running error:

 minimum eigenvalues =   0.516290976112914       0.635721497064936
  0.721411922551856
 maximum eigenvalues =    8727729.20865751        1896971.09878320
   425608.476260537
 num eigs kept =          256

I am not sure if the condition number is high. Or how to set mineig
keyword. When set PCA as 180 from GUI, AMICA can run on this dataset. I
also used the code from Makoto EEGlab webpage to test the data rank :
dataRank = sum(eig(cov(double(EEG.data'))) > 1E-7)
dataRank = rank(double(EEG.data'))
>From both code the data rank are 256.

Best,
Ke

On Fri, Mar 11, 2022 at 12:31 PM Jason Palmer <japalmer29 at gmail.com> wrote:

> Hi Ke,
>
> Could you check the output directory for and out.txt file for the 256
> channel runs?
>
> It may be that the data rank is much lower than the number of channels.
> You can check the lowest eigenvalues of the data with
> eig(cov(EEG.data(:,:)')). The mineig keyword option can be used to set the
> level of the minimum eigenvalue size to keep dimensions in PCA. Or you can
> set the number of dimensions to keep with the pcakeep keyword option.
>
> Best,
> Jason
>
> On Fri, Mar 11, 2022, 9:01 AM liao ke via eeglablist <
> eeglablist at sccn.ucsd.edu> wrote:
>
>> Dear all,
>>
>> I have a problem in running the AMICA and need your help.
>>
>> I have used AMICA to process some 128 channel EEG datasets recorded from
>> EGI system (reduced to 64 channels for calculation)  without any problem.
>> When I run AMICA on some 256 channel EEG data from the same system, it
>> always gives me the error message like:
>> 'No gm present, setting num_models to 1
>> No W present, exiting
>> Reference to non-existent field 'W'.
>>
>> Error in runamica15 (line 895)
>>     weights = mods.W(:,:,1);
>>
>> Error in pop_runamica (line 338)
>>     [W,S,mods] = runamica15(g.datfile,arglist{:});
>>
>> Error while evaluating Menu Callback.'
>>
>> This happens even I reduce the data into 183 channels. But when I further
>> reduce the data into 90 channels, the AMICA can run well. I am using AMICA
>> v1.6.1 with all default parameters from GUI.
>>
>> Is there any setting wrong with  my AMICA? Is there a channel limitation
>> with AMICA?
>>
>> Thanks very much for your help!
>> Ke
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