Dear Kambiz,
1) Haiteng makes a good point. You should make sure that you are using
the latest version of SPM8 because there have been some improvements
to enable handling of large files.
2) 1200 Hz is indeed quite high sampling rate for 275 channels. It'd
be a good idea to downsample your data in CTF software. Otherwise
everything will be very slow and unless you are interested in 600Hz
oscillations there is no reason to suffer.
3) The crash in your case happens already after the conversion when
SPM tries to display the data. You should perhaps try epoching or
downsampling the converted dataset that will be saved on the disk.
Epoching and downsampling functions read the data in small blocks so
it might work.
4) I don't know whether you used the 'just read' option but just in
case you did, there are also other options in spm_eeg_convert where
you can specify more precisely which part of the data should be read
and thereby reduce the size of your dataset. Read the manual.
5) Finally if nothing else helps perhaps you should work on a 64-bit
system and/or add some RAM to your computer.
Best,
Vladimir
On Wed, Aug 12, 2009 at 9:20 PM, Kambiz Tavabi<[log in to unmask]> wrote:
> When using spm_eeg_convert_ui (v3059) I run into a MATLAB out of MEMORY
> message. Matlab output attached as .txt.
>
> I am trying to convert 275 channel CTF data 1200 Hz sampling frequency,
> .meg4 file approx 1.3 Gb. I can't seem to figure out a work around (i.e.
> trying to define conversion parameters e.g. trials, MEG channels). Will I
> have to down sample the data? Or is some other work around possible?
>
> Any tip/advice appreciated.
>
>
>
> thanks
> Kambiz
>
> MATLAB OUTPUT FOR
> SPM8: spm_eeg_convert_ui (v3059) 16:02:58 - 12/08/2009
> ========================================================================
>
> SPM8: spm_eeg_channelselection (v2866) 16:03:35 - 12/08/2009
> ========================================================================
> converting units from 'cm' to 'mm'
> Warning: Could not obtain electrode locations automatically.
>> In spm_eeg_convert at 403
> In spm_eeg_convert_ui at 89
> converting units from 'cm' to 'mm'
> checkmeeg: no channel type, assigning default
> checkmeeg: no units, assigning default
> checkmeeg: transform type missing, assigning default
> checkmeeg: data scale missing, assigning default
> checkmeeg: data type is missing or incorrect, assigning default
> creating layout from cfg.grad
> creating layout for ctf275 system
> undoing the G3BR balancing
> ??? Error using ==> file2mat
> Memory Map (MapViewOfFile): Not enough storage is available to process this command.
>
> Error in ==> file_array.subsref>multifile2mat at 156
> val(cc(i)+1:cc(i+1)) = file2mat(obj,int32(1),int32(x(y==i)));
>
> Error in ==> file_array.subsref>subfun at 87
> t = multifile2mat(sobj,varargin{:});
>
> Error in ==> file_array.subsref at 60
> t = subfun(sobj,args{:});
>
> Error in ==> spm_eeg_review_callbacks at 52
> data = D.data.y(visuSensors,1:decim:D.Nsamples,:);
>
> Error in ==> spm_eeg_review>PSD_initUD at 203
> [out] = spm_eeg_review_callbacks('get','VIZU',D.PSD.MEG.I);
>
> Error in ==> spm_eeg_review at 33
> [D] = PSD_initUD(D);
>
> Error in ==> spm_eeg_convert_ui at 95
> spm_eeg_review(D);
>
> ??? Error while evaluating uicontrol Callback
>
>
>
>
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