[FieldTrip] Potential bug in trl

[Davide Rivolta]

Dear Jörn,

Thank you for your reply. I guess I have now figured it out.


Thanks,
Davide

On Fri, Aug 5, 2011 at 9:13 AM, "Jörn M. Horschig" <
jm.horschig at donders.ru.nl> wrote:

> Dear Davide,
>
> I never worked with trials of different length, however this should be
> straight forward when writing your own trialfun (just as Michael proposed).
> In most trialfuns, the trl matrix is constructed by concatenating the
> vectors begsample, endsample and offset. These vectors can have any values
> you want them to have. As a simple example, you can write a trialfun that
> just returns trl = [1 2 1; 400 500 100] (for your experiment, you of course
> want these values to be computed from your trigger values).
> Is your problem that such a thing does not work? It would be great if you
> give a concrete use-case, or e.g. attach your trialfun.
>
> Best,
> Jörn
>
>
> On 8/4/2011 4:03 PM, Davide Rivolta wrote:
>
> Thanks Michael,
>
>  I wrote my own trialfun.
>
>  The offset would be negative and would have the same lenght of difference
> between endsample-begsample. This, for each trial, would have a different
> value.
>
> It can be a bug. In fact, I tried to vhange the trialfun by leaving the
> same begsample and endsample, but I put a fixed offset (i.e., -100) and it
> worked. All the trial was in and not, like with the variable offset, until
> time = 0.
>
> Thanks,
>
> Davide
>
> On Thu, Aug 4, 2011 at 3:55 PM, Michael Wibral <michael.wibral at web.de>wrote:
>
>> Hi davide,
>>
>> I guess in such a case you would have to write your own trial function.
>> However, offset values larger than 0 mean, that the stimulus occured before
>> you start your piece of data - is that really what you wanted ?
>>
>> Michael
>>
>>
>>  ------------------------------
>> *Von:* "Davide Rivolta" <drivolta81 at gmail.com>
>> *Gesendet:* Aug 4, 2011 2:44:08 PM
>> *An:* fieldtrip at donders.ru.nl
>> *Betreff:* [FieldTrip] Potential bug in trl
>>
>>
>> Dear all,
>>
>> I have noticed that the trial definition works well when begsample,
>> ensample and offset have fixed values.
>>
>> I have however a specific trialfunction, where each trial has a different
>> lenght.
>>
>> This works well when you specify a fixed offset, however, when even the
>> offset has to change for each trial, Fieldtrip reports values until 0. It
>> ignores time after 0.
>>
>>
>> Might it be a bug?
>>
>> Thanks,
>>
>> Davide
>>
>>
>> _______________________________________________
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>> fieldtrip at donders.ru.nl
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>>
>
>
>
> --
> Davide Rivolta, PhD
>
>
>
> _______________________________________________
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>
>
>
> --
> Jörn M. Horschig
> PhD Student
> Donders Institute for Brain, Cognition and Behaviour
> Centre for Cognitive Neuroimaging
> Radboud University Nijmegen
> Neuronal Oscillations Group
>
> P.O. Box 9101
> NL-6500 HB Nijmegen
> The Netherlands
>
> Contact:
> E-Mail: jm.horschig at donders.ru.nl
> Tel:    +31-(0)24-36-68493
> Web: http://www.ru.nl/donders
>
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>
>
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-- 
Davide Rivolta, PhD
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