Hi Cherif,
I'm guessing that FEAT can cope with empty EVs but maybe not empty
contrasts or contrasts that refer to empty EVs. Probably the best
thing to do is to exclude the empty EVs and select COPEs for feeding
up to higher-level by hand using the "inputs are lower level COPEs"
option at higher level.
Cheers, Steve.
On 18 Feb 2007, at 23:23, Cherif Sahyoun wrote:
> Hi!
>
> I have 6 runs/subject, each of which shows 2 out of 3 conditions.
> I was planning the analysis like this in Feat:
> have 4 EVs (cond1, cond2, cond3, errors), and put in an empty (0 0 0)
> three-column format file for whenever a condition does not exist in
> a given
> run (or when there are no errors instead of the errors file).
> This would then allow me to do a second-level session to put
> together all my
> runs, so that all EVs and contrasts are identical across lower-
> level feat
> directories, even if some are empty. (This was taken from the
> ...fsl/feat5/detail.html page, under EV's).
> As expected, I got a rank deficiency warning, but on top of that, I
> got:
>>>
> An exception has been thrown
> Runtime error:- detected by Newmat: matrix is singular
>>>
> which was then followed by failure to find a number of files in the
> stats
> subdirectory of Feat, and everything went downhill from there.
>
> Any ideas?
> Thanks!
> cherif
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Stephen M. Smith, Professor of Biomedical Engineering
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