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Bug 3073 - correct computation of coh and plv fails with fourier input
| Status | CLOSED FIXED |
| Reported | 2016-02-19 10:45:00 +0100 |
| Modified | 2016-05-05 20:29:41 +0200 |
| Product: | FieldTrip |
| Component: | core |
| Version: | unspecified |
| Hardware: | PC |
| Operating System: | Windows |
| Importance: | P5 normal |
| Assigned to: | Jan-Mathijs Schoffelen |
| URL: | |
| Tags: | |
| Depends on: | |
| Blocks: | |
| See also: |
Daniel Hähnke - 2016-02-19 10:45:08 +0100
Hello, I downloaded the most recent version of fieldtrip for a new computer and wanted to compute PLV. Here is the code that I used: cfg.method = 'plv'; cfg.channelcmb = {'AD01' 'AD02'}; ft_connectivityanalysis(cfg, data) data is a structure with a field 'fourierspctrm'. The error I get is the following: Matrix dimensions must agree. Error in ft_connectivityanalysis (line 860) if all(size(varout) == size(nrpt)) I'm absolutely sure that this is an issue of this version, since an older version that I'm using, 20151019, does not suffer from this bug. Regards, Daniel
Jan-Mathijs Schoffelen - 2016-02-19 11:00:03 +0100
I cannot reproduce it. Please add some data so that we can look into it.
Daniel Hähnke - 2016-02-19 12:27:01 +0100
I can't upload it here, since the file is too big. Here is a link to Google Drive https://drive.google.com/file/d/0B00Xa5d3xaB9SGN4TW42TU1lSkU/view?usp=sharing
Jan-Mathijs Schoffelen - 2016-02-19 13:23:46 +0100
OK, I can reproduce it. It seems to be caught in this error only with TF-data (I initially tried to reproduce on freq-only data). Also, it runs without error if you DON't specify a channelcmb in the cfg. Yet, I stumbled onto something far more serious, and this relates to how the individual trials are handled. There's a major bug at the moment that now the coh/plv is computed per trial and averaged later on. This leads to all-ones when just a single taper per trial is used.
Jan-Mathijs Schoffelen - 2016-02-19 13:34:28 +0100
Hi Daniel, my version of fieldtrip on github.com/schoffelen/fieldtrip should contain a fixed version (as well as the github.com/fieldtrip/fieldtrip.git repository). Could you update your code and see whether it works again? Sorry for the inconvenience
Daniel Hähnke - 2016-02-19 14:39:32 +0100
That resolves it, thanks! By the way, I also tested version 20160205, which has the bug, and 20160101, which doesn't. So the bug must have appeared somewhere in between these versions. You probably have a handy version tracker software that shows you when in appeared ;)