[Eeglablist] Error resample tmpMMO

[Arnaud Delorme]

Dear Angelica,

You can also use File-IO extension to import as memory mapped data (data stays on disk). Did you try that? I have just tried and it worked fine (imported a file as memory mapped and resampled it).

The memory mapped functions are marked as beta, and there are potential issues when using them. The best is to do what you did, import the data as memory mapped and resample it so it fits in memory. This is the default by the way if you just check the box “import as memory mapped data” in File-IO or BIOSIG. The files are imported as memory mapped. However, as soon as you modify them (resample them or select a portion of the data) they are stored in regular memory (so no longer processed on disk). If you want to continue processing the data as memory mapped data, you can go in the preferences, and check the memory mapped checkbox. However, again, this is not something we recommend (almost no one use this functionality so, although we have test cases, it might not be robust). In case you do not have enough RAM, the best option when using EEGLAB is to get more RAM (although importing as memory mapped and resampling before processing is fine as well).

Best wishes,

Arno

> On Mar 15, 2024, at 2:29 AM, Angelika Wolman via eeglablist <eeglablist at sccn.ucsd.edu> wrote:
> 
> Hi,
> 
> I imported .bdf files (one containing the data, the other events) to EEGLAB via this function:
> EEG = pop_importNeuracle({dataNames,event_bdf_names},subfold,'memorymapped','on');
> I used the memorymapped option because otherwise it didn't work.
> 
> Now I want to preprocess my data and find an error when using the function:
> EEG = pop_resample(EEG, 500);
> The error is:
> 1 Error using indexing
> A subscripting operation on the Data field
> attempted to create a comma-separated list.
> The memmapfile class does not support the
> use of comma-separated lists when
> subscripting.
> 
> Error in indexing (line 81)
>    res = tmpMMO.data.x(subs{:});
> 
> Error in pop_resample (line 155)
>    sigtmp = reshape(EEG.data(index1,:, :),
>    oldpnts, EEG.trials);
> 
> Error in preproc (line 29)
>    EEG = pop_resample(EEG, 500);
> 
> Any ideas what I can do? I don't think this question has been asked already.
> 
> Thank you very much!
> Angelika
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