CPU cores/threads used

[NunoMac]

Hi, I m running ANTs on a server. My question is: will it run using the maximum number of threads available? Or is it a good idea to define that manually?

Right now, i am applying the following to do the registration:
-d 3
--float 0
-v 1
-o [${output},${output}.nii.gz]
--interpolation WelchWindowedSinc
--use-histogram-matching ${histomatching}
--winsorize-image-intensities [0.005,0.995]
--initial-moving-transform [${fixed},${moving},0]
-t rigid[${lstep}]
-m MI[${fixed},${moving},1,32,Regular,0.25]
-c [200x200x200x0,${convlin},10]
--shrink-factors 8x4x2x1
--smoothing-sigmas 3x2x1x0vox
-t Affine[${lstep}]
-m MI[${fixed},${moving},1,32,Regular,0.25]
-c [200x200x200x0,${convlin},10]
--shrink-factors 8x4x2x1
--smoothing-sigmas 3x2x1x0vox
-t SyN[${synstep},${synpenalty1},${synpenalty2}]
-m CC[${fixed},${moving},1,${ccradius}]
-c [200x200x100x50,${convsyn},10]
--shrink-factors 8x4x2x2
--smoothing-sigmas 4x3x2x1vox \

should I add
'-n 8' at the begining to force the use of 8 threads?

I haven't found this being used in other scripts...

Thanks!

Nuno

[cookpa]

Multi-threading in ITK filters is controlled by the environment variable ITK_GLOBAL_DEFAULT_NUMBER_OF_THREADS. Some of the ANTs scripts allow this to be set dynamically with -n, but if you are running the antsRegistration binary directly, you'll want to set the variable.

[NunoMac]

Thank you for the tips! I set it to run on the server environment as environment = "ITK_GLOBAL_DEFAULT_NUMBER_OF_THREADS=8" (I read that the gains above 8 are probabyl not worth it) and will check if it worked and improved processing time.