Hi Andi - The most common problem that would cause all or almost all pathways to fail is an incorrect gradient table. You can do a sanity check on that by looking at the primary eigenvectors from your tensor fit (dmri/dtifit_V1.nii.gz). See also my answer to Fernando earlier today.
Hope this helps, a.y
On Tue, 30 Oct 2012, Andi Heckel wrote:
Dear Tracula team,
I have noticed in a multisubject tracula analysis, that the posterior density in many if not all paths in the path.pd.nii.gz file is just a bright one-dimensional curve, rather than a true distribution. The path.map.nii.gz is empty. This is true for both flirt and bbreg registered versions in many subjects. Trac-all finished wiithout errors. So did Recon-all.
Could it actually be a memory (RAM) problem ? We are running tracula on a cluster with only 2.5 GB per core.
thx for any help and kind regards, andi