Hi all,
I'm having some problems getting a second level fixed effects analysis started on my subjects. There are three runs (dofsum = 884) in each case I'd like to compare.
OSGM works fine so far, but when I apply a matrix like this:
1 0 0 0 1 0 0 0 1
To a contrast like that:
0.5 0.5 -1
mri_glmfit tells me: ERROR DOF = 0.
I also tried it with an FSGD file, so my approach was the same as for the Fsgdf3G0V example (http://surfer.nmr.mgh.harvard.edu/fswiki/Fsgdf3G0V). That makes no difference.
When I divide the three runs into two classes, everything works fine again. But why the error with three classes?
Any ideas?
Thanks, Georg
$ mri_glmfit --surf 01 lh --y 01/gender.lh.cope1.sm05.mgz --yffxvar 01/gender.lh.varcope1.sm05.mgz --ffxdof 884 --glmdir 01/results/gender.sm05.lh --X xmat.mat --C test.mat --label $SUBJECTS_DIR/01/label/lh.cortex.label Reading source surface /data/freesurfer/01/surf/lh.white Number of vertices 149696 Number of faces 299388 Total area 96879.085938 AvgVtxArea 0.647172 AvgVtxDist 0.880017 StdVtxDist 0.256396
$Id: mri_glmfit.c,v 1.138.2.10 2009/05/18 15:41:44 greve Exp $ cwd /data/freesurfer/higher/highest/fixed cmdline mri_glmfit --surf 01 lh --y 01/gender.lh.cope1.sm05.mgz --yffxvar 01/gender.lh.varcope1.sm05.mgz --ffxdof 884 --glmdir 01/results/gender.sm05.lh --X xmat.mat --C test.mat --label /data/freesurfer/01/label/lh.cortex.label sysname Darwin FixVertexAreaFlag = 1 UseMaskWithSmoothing 1 OneSampleGroupMean 0 y /data/freesurfer/higher/highest/fixed/01/gender.lh.cope1.sm05.mgz logyflag 0 X xmat.mat usedti 0 labelmask /data/freesurfer/01/label/lh.cortex.label maskinv 0 glmdir 01/results/gender.sm05.lh IllCondOK 0 DoFFx 1 FFxDOF 884 yFFxVar /data/freesurfer/higher/highest/fixed/01/gender.lh.varcope1.sm05.mgz Creating output directory 01/results/gender.sm05.lh Loading y from /data/freesurfer/higher/highest/fixed/01/gender.lh.cope1.sm05.mgz Loading yffxvar from /data/freesurfer/higher/highest/fixed/01/gender.lh.varcope1.sm05.mgz Saving design matrix to 01/results/gender.sm05.lh/Xg.dat Matrix condition is 1 /data/freesurfer/01/label/lh.cortex.label /data/freesurfer/01/label/lh.cortex.label Found 141245 points in label. Pruning voxels by thr: 0.000000 Found 141245 voxels in mask Saving mask to 01/results/gender.sm05.lh/mask.mgh search space = 91409.8 DOF = 0 ERROR: DOF = 0