hi all
estimating a single subject in a mixed block/event-related design under
SPM2, I get the following error:
Error in ==> spdiags at 114
a((len(k)+1):len(k+1),:) = [i i+d(k) B(i+(m>=n)*d(k),k)];
Error in ==> spm_spm at 420
s = spdiags(1./sqrt(diag(s)),0,nScan,nScan);
??? Error while evaluating uicontrol Callback.
this error is preceded by warnings about the matrix being singular to
working precision (and all the values in SPM.xVi.V are NaN).
this has come up on the list a few times, but typically in analysis at the
group level (not the subject level as here). It seems to be related to the
estimate of error covariance, for example
http://www.jiscmail.ac.uk/cgi-bin/wa.exe?A2=ind04&L=spm&P=R60065&I=-1
In our design, we have (3) blocks of one type of trials (not of interest)
interleaved with (3) types of events of interest (12 regressors total).
Any suggestions would be most welcome.
thanks,
Chris
Christopher Summerfield
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