[FieldTrip] Different results with source reconstruction from July 2018 and onwards

[Frans Nord]

Thank you so much for your quick response Jan-Mathijs!

I agree, the change is not huge when looking at individual level but it is
definitely there and it makes a big difference later on in our analysis
pipeline. Maybe this is a sign that our analysis method is weak but let's
not get there yet.

I get this result when running the analysis on either an OS:X machine or a
machine with Windows 10. The difference in output between the fieldtrip
versions is there in both OS's.

I'll attach a calculated power spectrum on group level for pre and post
commit so it becomes clearer. These are calculated with the same config
file in ft_freqanalysis and then contrasted in the same way with the same
classes that we look at. Sure, it's the same overall shape but there should
not be any difference at all imo. To triple check what I'm doing I
downloaded the two versions again today and ran them through our analysis
and I still get the same difference.

This has been bugging me for close to a month now and I can't seem to
figure it out on my own so your help is much appreciated!

Best regards
Frans


On Mon, Dec 6, 2021 at 6:49 PM Schoffelen, J.M. (Jan Mathijs) via fieldtrip
<fieldtrip at science.ru.nl> wrote:

> Dear Frans,
>
> Why do you say that there’s a ‘huge’ change? I hardly see the difference,
> that is the most prominent features in the time series are pretty
> comparable I’d say.
>
> Just to be clear on this: are you comparing the results across operating
> systems? At this point I don’t see any changes in the code from 11 to 12
> July 2018 that at first sight would affect your analysis. The ‘guilty’
> commit is a merge of a PR by Sarang that pertains to (bookkeeping of data
> needed for) forward computations using openmeeg as a method. I don’t see
> how that would affect your analysis pipeline, if it is sufficiently close
> to the one on OSF that you refer to.
>
> Best wishes,
> Jan-Mathijs
>
>
>
>
>
>
> On 6 Dec 2021, at 16:59, Frans Nord via fieldtrip <fieldtrip at science.ru.nl>
> wrote:
>
> Hello all,
>
> I get different results with the same source reconstruction code when
> using Fieldtrip before 11 July 2018 compared to 12 July 2018. The results I
> get from before the twelfth seems to be more in line with previous found
> intracranial results and measurements on sensor level. I'm using eLORETA
> and the code is basically the same as this:
> https://osf.io/bgfs5/?view_only=ebb85532e1064d128db79bacb6be27f8
> <https://urldefense.com/v3/__https://osf.io/bgfs5/?view_only=ebb85532e1064d128db79bacb6be27f8__;!!HJOPV4FYYWzcc1jazlU!_AyLxWa-VXiG3g1vjZDuQdq7Ze9eST4_qjhy9H4t0vaBg2DIzlz-a283UfUGtsZL3SLJzRwNkeK-Jwyb22bpLfLvJvxdqgnfvxtpvQ$>
>
> The 'pre' attached file is how the first trial for the first participant
> look with the version before july 11 and the 'post' is after july 11.
>
>  - Operating System:  Windows 10 and Mac os:x Mojave
>  - MATLAB version: R2019a
>  - FieldTrip version: fieldtrip-171478a3e1c71f499ad0cf01f661dbb257ff5eb5
> and fieldtrip-d1aa34272c61454dbbd9684f836c68b2dd26f337
>
>
> What was it that justified such a huge change in the model? Can I read
> about it somewhere? Note that this is not the problem described in
> https://github.com/fieldtrip/fieldtrip/issues/1020
> <https://urldefense.com/v3/__https://github.com/fieldtrip/fieldtrip/issues/1020__;!!HJOPV4FYYWzcc1jazlU!_AyLxWa-VXiG3g1vjZDuQdq7Ze9eST4_qjhy9H4t0vaBg2DIzlz-a283UfUGtsZL3SLJzRwNkeK-Jwyb22bpLfLvJvxdqgk-MKNj-g$>
> but appeared in an earlier version.
>
> Best regards
> Frans
> <post.png><pre.png>_______________________________________________
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> https://urldefense.com/v3/__https://doi.org/10.1371/journal.pcbi.1002202__;!!HJOPV4FYYWzcc1jazlU!_AyLxWa-VXiG3g1vjZDuQdq7Ze9eST4_qjhy9H4t0vaBg2DIzlz-a283UfUGtsZL3SLJzRwNkeK-Jwyb22bpLfLvJvxdqgnxcbBYwg$
>
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