Re: [Freesurfer] selxavg3 error : NaN in Xtmp.mat file

If you have an event type for which there is no event, then that is definitely the problem. Let me know if it is not that. doug

Sid Kundu wrote:

It is attached. Finn mentioned it may be due to an event number being missing from the particular subject, which could be possible in the analysis I am doing. _________________________________ Sid Kundu Biomedical Engineering Boston University

On Thu, Mar 1, 2012 at 11:15 AM, Douglas N Greve <greve@nmr.mgh.harvard.edu mailto:greve@nmr.mgh.harvard.edu> wrote:

It's probably a problem with your design. Can you send me the
Xtmp.mat file?
doug


Sid Kundu wrote:

    Hi Doug,

    I created a new first level analysis along with new contrasts
    and event numbers for a group of subjects I had previously
    done analyses on. All but one of the subjects finished
    selxavg3 without error, but one subject gave the following error:


    Saving X matrix to
    /home/sidkundu/freesurfer/sessions/Heading-TTP/LMV2010_N19_Heading-TTP/bold/TTP-analysis-3/Xtmp.mat
    Error using svd
    Input to SVD must not contain NaN or Inf.

    Error in cond (line 39)
      s = svd(A);

    Error in fast_selxavg3 (line 248)
     XCond = cond(XtX);
     >> ------------------------------------------
    ERROR: fast_selxavg3() failed\n


    I looked at the generated Xtmp.mat file and it shows the
    design matrix X has all zeros in 2 columns, resulting in NaNs
    in the same columns for Xn, and corresponding NaNs in XtX. I'm
    wondering what would cause this or why it would only occur for
    only one subject.

    _________________________________
    Sid Kundu
    Biomedical Engineering
    Boston University


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Douglas N. Greve, Ph.D.
MGH-NMR Center
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