Dear Johannes,
Thank you for spotting the error with the BMS.DCM.rfx.BF field.
This field existed in SPM8b but has been replaced by BMS.DCM.rfx.SF.
The visualisation routines for BMS for DCM have been corrected.
Regarding your first question: I was wondering how many models you compared...
I've used more than 20 models and haven't come across any memory problems.
Best regards,
Maria
On Tue, Apr 21, 2009 at 4:54 PM, Johannes Tünnerhoff
<[log in to unmask]> wrote:
> Dear all,
>
> I have two questions concerning BMS in spm8:
>
>
>
> 1. There is an out of memory error when comparing (rfx) too many models in
> spm_dirichlet_conj_exceed.m because the 'r-matrix' becomes too big.
>
> See line 37: r(:,k) = spm_gamrnd(alpha(k),1,Nsamp,1);
>
>
>
> I think I found a workaround:
>
> By saving the gamma distribution for each model alpha in a .mat-file,
> the working memory cost can be lowered.
>
> Afterwards each mat-file is loaded when needed for comparison. This way it
> takes longer, but the results don't seem to differ from the original script
> (due to spm_gamrnd the results (xp) differ for every run slightly, so I
> checked twice: first by using another function and second by comparing the
> variation of the results) when comparing few models.
>
> Further details can be found in spm_dirichlet_conj_exceed_by_jotue.m
> as attached.
>
>
>
> 2. When viewing the results of BMS using the matlabbatch I get an error: the
> field BMS.DCM.rfx.BF does not exist.
>
> This is not the case if the results are displayed after estimation.
>
>
>
> When I replace BMS.DCM.rfx.BF with BMS.DCM.rfx.SF and BMS.DCM.ffx.BF with
> BMS.DCM.ffx.SF in the file spm_run_bms_dcm_vis.m
>
> It seems to work.
>
>
>
> Did anyone else encounter these problems?
>
> Is my way to fix it correct?
>
>
>
> Thank you
>
> Johannes Tuennerhoff
>
>
>
>
>
>
>
>
>
> -----------------------------------------------
> Johannes Tünnerhoff
> Max Planck Institute for Biological Cybernetics
>
> Cognitive Neuroimaging
> Spemannstraße 41
> 72076 Tübingen
> Telephone: +49-7071-601 1785
> Telefax: +49-7071-601 616
>
> Website: <http://www.kyb.mpg.de/~jotue> http://www.kyb.mpg.de/~jotue
>
> -----------------------------------------------
>
>
>
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