Guten Tag, 

Hi, 


Ich bin vom 05.02.2023 bis 10.02.2023 nicht im Büro und kann die
Emails nur sehr unregelmäßig lesen und beantworten. Die Emails werden
auch nicht weitergeleitet.  


I am out of the office from 05.02.2023 to 10.02.2023 and can only read
and answer emails very sporadically. The emails are also not being
forwarded.  


Viele Grüße / Best regards

Stephan Frisch



Am 07.02.2023 um 00:32 schrieb Ruoyi Cao via fieldtrip
<<fieldtrip@science.ru.nl>:


<excerpt><color><param>0000,0000,0000</param>Hi Jan-Mathijs: 

Thank you so much for your fast response ! This is exactly the
problem. There is one empty event in the bdf file. 


Best wishes,

Ruoyi



On Mon, Feb 6, 2023 at 10:35 PM Schoffelen, J.M. (Jan Mathijs) via
fieldtrip
<<</color><underline><color><param>08B3,4F87,D1D1</param>fieldtrip@science.ru.nl</color></underline><color><param>0000,0000,0000</param>>
wrote:

Hi Ruoyi,


I don’t know about the specific file format you are working with, but
- occasionally in some file formats - some events may have an empty
value. As a consequence, the code that you used in your selfmade
function may not have been absolutely robust. Specifically, the three
lines:


<bold><italic>value2 = {event.value}.';</italic></bold>

<bold><italic>value=cell2mat(value2)</italic></bold>

<bold><italic>sample = [event.sample].’</italic></bold>

<bold><italic>

</italic></bold>lead to two vectors (value and sample) that are
assumed to relate to each other one-by-one, meaning that element -i-
in one of the vectors corresponds to element -i- in the other vector.

I would first check if this is really the case in your data. If not, I
think that this explains the discrepancy you report, and would be
indicative that you may need to change your own code a bit, in order
to obtain the expected behavior. You could quickly check this: a = {1
2 [] 3}; b = cell2mat(a); As you will see, ‘a’ has 4 elements, ‘b’
only 3...


Best wishes,

Jan-Mathijs




</color><color><param>45BA,3BDE,CD06</param>On 6 Feb 2023, at 20:33,
Ruoyi Cao via fieldtrip
<<</color><underline><color><param>08B3,4F87,D1D1</param>fieldtrip@science.ru.nl</color></underline><color><param>45BA,3BDE,CD06</param>>
wrote:


<bold><fontfamily><param>Arial</param>Hello FieldTrip community,

I segmented data by triggers after artifact correction on continuous
data , where all deleted parts were replaced with NaN. Then this data
mat was segmented with ft_trialfun_general and with a self made
function as follows. The NaN value was later deleted after the output
was time locked to the trigger.</fontfamily></bold>


<bold><fontfamily><param>Arial</param>I am very confused as the
outcome from my self-made function was surprisingly not the
same. Could anyone kindly give me some ideas for why this is the case
and how to fix the problem? </fontfamily></bold>

<bold><fontfamily><param>Arial</param>


Thank you so much </fontfamily></bold>

<bold><fontfamily><param>Arial</param>Ruoyi.</fontfamily></bold>

<bold><fontfamily><param>Arial</param>

The two methods are as follows: </fontfamily></bold>

<bold><italic>Standard code: </italic></bold>

<bold><italic>

1: </italic></bold>

<bold><italic>cfg = [];</italic></bold>

<bold><italic>cfg.dataset             = M</italic></bold>

<bold><italic>% cfg.trialdef.pre    =  2.5;</italic></bold>

<bold><italic>%
</italic></bold></color><bold><italic><underline><color><param>08B3,4F87,D1D1</param>cfg.trialdef.post</color></underline><color><param>45BA,3BDE,CD06</param> 
 =  1.5;</color></italic></bold><color><param>45BA,3BDE,CD06</param>

<bold><italic>cfg.trialdef.eventtype      = 'STATUS';</italic></bold>

<bold><italic>cfg.trialdef.prestim        = 2.5; % in seconds</italic></bold>

<bold><italic>cfg.trialdef.poststim       = 1.5; % in seconds</italic></bold>

<bold><italic>cfg.trialdef.eventvalue = 101;</italic></bold>

<bold><italic>cfg_B1 = ft_definetrial(cfg);</italic></bold>

<bold><italic>segbinding1= ft_redefinetrial(cfg_B1,data); </italic></bold>

<bold><italic>Reference: </italic></bold>

</color><bold><italic><underline><color><param>08B3,4F87,D1D1</param>Preprocessing
- Reading continuous EEG and MEG data - FieldTrip toolbox</color></underline></italic></bold><color><param>45BA,3BDE,CD06</param>


<bold><italic>2:  Self made function according to
following instruction : </italic></bold>

<bold><italic>

function [trl, event] =location1(cfg);

hdr   = ft_read_header(cfg.dataset);</italic></bold>

<bold><italic>event = ft_read_event(cfg.dataset);</italic></bold>

<bold><italic>% search for "trigger" events</italic></bold>

<bold><italic>% value  = [event(find(strcmp('trigger',
{event.type}))).value]';</italic></bold>

<bold><italic>value2 = {event.value}.';</italic></bold>

<bold><italic>value=cell2mat(value2)</italic></bold>

<bold><italic>% sample = [event(find(strcmp('trigger',
{event.type}))).sample]';</italic></bold>

<bold><italic>sample = [event.sample].'</italic></bold>

<bold><italic>% determine the number of samples before and after the
trigger</italic></bold>

<bold><italic>pretrig  = -round(cfg.trialdef.pre  * hdr.Fs);</italic></bold>

<bold><italic>posttrig = 
round(</italic></bold></color><bold><italic><underline><color><param>08B3,4F87,D1D1</param>cfg.trialdef.post</color></underline><color><param>45BA,3BDE,CD06</param>
* hdr.Fs);</color></italic></bold><color><param>45BA,3BDE,CD06</param>

<bold><italic>% for each trigger except the last one</italic></bold>

<bold><italic>trl = [];</italic></bold>

<bold><italic>for j = 1:(length(value)-3)</italic></bold>

<bold><italic>           trg1 = value(j); </italic></bold>

<bold><italic>if (trg1==101);</italic></bold>

<bold><italic>trlbegin = sample(j) + pretrig;</italic></bold>

<bold><italic>trlend   = sample(j) + posttrig;</italic></bold>

<bold><italic>offset   = pretrig;</italic></bold>

<bold><italic>newtrl   = [trlbegin trlend  offset ];;</italic></bold>

<bold><italic> trl      = [trl; newtrl]   </italic></bold>

<bold><italic>end</italic></bold>

<bold><italic>end</italic></bold>

<bold><italic>

This function was run with : </italic></bold>

<bold><italic>cfg = [];</italic></bold>

<bold><italic>cfg.dataset             = M</italic></bold>

<bold><italic>cfg.trialdef.pre    =  2.5;</italic></bold>

</color><bold><italic><underline><color><param>08B3,4F87,D1D1</param>cfg.trialdef.post</color></underline><color><param>45BA,3BDE,CD06</param> 
 =  1.5;</color></italic></bold><color><param>45BA,3BDE,CD06</param>

<bold><italic>cfg.trialfun = 'location1';</italic></bold>

<bold><italic>cfg_B1 = ft_definetrial(cfg);</italic></bold>

<bold><italic>segbinding1= ft_redefinetrial(cfg_B1,data);</italic></bold>

<bold><italic>References </italic></bold>

</color><bold><italic><underline><color><param>08B3,4F87,D1D1</param>Making
your own trialfun for conditional trial definition - FieldTrip toolbox</color></underline><color><param>45BA,3BDE,CD06</param>

</color></italic><fontfamily><param>Comic Sans MS</param><color><param>45BA,3BDE,CD06</param>

</color></fontfamily><italic><fontfamily><param>Arial Narrow</param><color><param>45BA,3BDE,CD06</param>The
following excels shows two different trial definitions given by these
two methods. The highlighted value is the differences between the
beginning of each segment for each detected trial between two methods. </color></fontfamily></italic></bold><color><param>45BA,3BDE,CD06</param>

<bold><italic>

<<image.png></italic></bold>

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</color></excerpt>