[FieldTrip] Issues with ft_combineplanar(cfg, data)

Eelke Spaak eelke.spaak at donders.ru.nl
Tue Apr 9 16:58:54 CEST 2013


Hi Nic,

Good to hear the problem has been solved.

If you append multiple data sets, ft_appenddata discards gradiometer
information because this might be different in the different data
sets. If you are certain one particular gradiometer definition is
correct for the appended data, you can simply 'artificially attach it
again'.

Best,
Eelke

On 9 April 2013 16:45, Niccolò Pescetelli <niccol000 at yahoo.it> wrote:
> Thank you Eelke.
>
> I found out that the problem was before calling the combine planar function.
> The original script read in 5 files of raw data (which I could not upload in
> dropbox, due to dimensions issues). These have the .grad field, but when I
> appenddata() the data structure looses its grad field.
>
> I managed to artificially attach it again, but I don't understand why the
> function ft_appenddata() does this
> Any idea?
>
> I will try to send you the files in a way or the other
>
> Best
>
> Nic
>
>
>
> ________________________________
> Da: Eelke Spaak <eelke.spaak at donders.ru.nl>
> A: FieldTrip discussion list <fieldtrip at science.ru.nl>
> Inviato: Martedì 9 Aprile 2013 11:50
> Oggetto: Re: [FieldTrip] Issues with ft_combineplanar(cfg, data)
>
> Dear Nic,
>
> That is very weird. The fact that a grad seems to be created out of
> thin air by ft_combineplanar suggests to me that there might be an
> error in your script. (However, of course it could also be a bug in
> fieldtrip.) Could you perhaps send a functional (small) piece of data,
> along with a script, that reproduces the error? Your e-mail currently
> does not have enough information to judge what's truly going on. If
> your data is >1MB, please use one of the file sharing services listed
> here:
> http://fieldtrip.fcdonders.nl/faq/how_should_i_send_example_data_to_the_developers
>
> Best,
> Eelke
>
> On 9 April 2013 10:33, Niccolò Pescetelli <niccol000 at yahoo.it> wrote:
>> Dear all,
>>
>> I am new to fieldtrip and I would like to have your opinion about a
>> bizarre
>> error that I find trying to execute the function ft_combineplanar(). What
>> am
>> I trying to do is to  obtain the planar gradient from raw data. I use a
>> neuromag306 Elekta MEG system.
>> I tried to dig deeper into the scripts and I notice some quirks the error
>> could derive from:
>>
>> 1. as soon as I call ft_combineplanar(cfg, data) , data.trials switches
>> from
>> 840 trials to 192 trials, without any command being provided that is
>> BEFORE
>> the first line of ft_combineplanar(cfg, data) being executed! At the same
>> time all data.trials becomes empty arrays
>>
>> 2. my data structure does not contain the fields 'grad' before
>> ft_combineplanar(cfg, data) has been called but it does afterwards . Again
>> this happen without any command having been given
>>
>> 3. The error finally occurs in line 210 of the ft_combineplanar function
>> (indexing error) and it's due to the data.trial array being empty
>>
>> What do you think?
>>
>> Best
>>
>> Nic
>>
>> _______________________________________________
>> fieldtrip mailing list
>> fieldtrip at donders.ru.nl
>> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
>
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