[FieldTrip] (no subject)

[Eelke Spaak]

Dear Vita,

On 27 January 2012 12:32, Cardinale, Vita (Stud. FPN / Alumni)
<m.cardinale at student.maastrichtuniversity.nl> wrote:
> I get this warning:
>
> no trialfun was specified, using trialfun_general
>> In ft_definetrial at 123
> evaluating trialfunction 'trialfun_general'

This means that ft_definetrial is using trialfun_general as the
function to determine the trials-of-interest in your data. This is the
default if you do not specify cfg.trialfun yourself, and is the proper
setting for running the tutorial. So, nothing to worry about here.

>
> Warning: adding D:\Vita\fieldtrip-20120124\external\ctf toolbox to your
> Matlab path
>

Also as it should be; FT issues warnings whenever a toolbox is
automatically added to your path.

> readCTFds: Data set error : size of meg4 file(s)
>            0 bytes (from dir command)
>    179071200 bytes (from res4 file)
>
>
> together with this output:
>
>
>
> hdr =
>
>              Fs: 300
>          nChans: 187
>        nSamples: 900
>     nSamplesPre: 300
>         nTrials: -1
>           label: {187x1 cell}
>            grad: [1x1 struct]
>            orig: [1x1 struct]
>        chantype: {187x1 cell}
>        chanunit: {187x1 cell}
>
>
>
> which according to the tutorial should be:
>
>
>
> hdr =
>
>
>
>              Fs: 300           % sampling frequency
>
>          nChans: 187           % number of channels
>
>        nSamples: 900           % number of samples per trial
>
>     nSamplesPre: 300           % number of pre-trigger samples in each trial
>
>         nTrials: 266           % number of trials
>
>           label: {187x1 cell}  % cell-array with labels of each channel
>
>            grad: [1x1 struct]  % gradiometer structure
>
>            orig: [1x1 struct]  % additional header information
>

This actually is indicative of a problem. The extra chantype and
chanunit fields are fine, they are just new fields that were not
present at the time the tutorial was written. The nTrials = -1 issue,
together with the "data set error" message you mentioned, means that
something is going wrong when reading in the data.

The first thing that comes to mind on what causes this is improper
directory settings. Since your e-mail was sent through the Donders
SMTP server, I am guessing you are located at the DCCN, am I right?
You could try specifying the full path to the test dataset:

cfg.dataset = '/home/common/matlab/fieldtrip/data/Subject01.ds';

If that still does not work, let us know.

Best,
Eelke

>
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