I was trying to compile Freesurfer (in a Centos 6.5 VM) with a later gcc to see if the performance improved and noticed that the output gcc 4.4 vs. 4.8 was slightly different. I later compiled with gcc 4.4 *without* openmp support and this version produced the same output as the gcc 4.8 version, as expected. I have attached the recon-all log files, they first differ at line 1664, at iteration 451 of mri_ca_register; after that the differences accumulate. I feel that this shouldn’t happen and the outputs should be equivalent.

 

As a side note, I am unable to compile GEMS and dmri_poistats or any of the GUI programs due to vtk undefined symbols errors. Similar to this http://www.vtk.org/pipermail/vtkusers/2010-September/062426.html. This is apparently a known issue with vtk 5.6. How is this resolved?

 

PS. The gcc 4.8 binaries were slower than the 4.4 binaries.

 

Thanks in advance,

 

Chris.

 

Dr Chris Adamson  
Research Officer, Developmental Imaging, Murdoch Childrens Research Institute 
Murdoch Childrens Research Institute 
Royal Children’s Hospital
Flemington Road, Parkville, Victoria  3052, Australia
www.mcri.edu.au

E   chris.adamson@mcri.edu.au
T   03 9936 6780