Hello all,

I see unexpected behavior when I use 'fslcc'.  I get no output when I use the '--noabs' switch.

I want to see if two eigenvariate time courses I extracted via 'fslmeants' are flipped with respect to one another.  I extract the time courses:

  fslmeants -i filtered_func \
     -m hippoLeft -o tc_eig_hippoLeft.txt --eig

  fslmeants -i filtered_func \
     -m hippoRight -o tc_eig_hippoRight.txt --eig

I convert these ascii files to .nii:

  nn=`fslnvols filtered_func `
  fslascii2img tc_eig_hippoLeft.txt  \
     $nn 1 1 1 1 1 1 1 vol_eig_tc_eig_hippoLeft
  fslascii2img tc_eig_hippoRight.txt \
     $nn 1 1 1 1 1 1 1 vol_mean_tc_eig_hippoRight

Then compute the cross correlation without and with the --noabs switch:

  # without --abs switch
  fslcc -t 0 -p 6 vol_eig_tc_eig_hippoLeft vol_mean_tc_eig_hippoRight
    1   1 0.838791

  # with --abs switch
  fslcc --noabs -t 0 -p 6 vol_eig_tc_eig_hippoLeft vol_mean_tc_eig_hippoRight

When I plot these two eigenvariates, I can see they are anti-correlated.  In the above example, when using the --noabs switch I expected a negative value, -0.838791.  Instead, I get no output.

Just in case, I also tried --noabs=1 and --noabs=0 and got no output.  I also moved the position of the --noabs switch within the command -- still no output.  Any suggestions?

I am trying to avoid popping into matlab.

Thanks,
* ba