AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

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bob cox
January 10, 2003 06:20PM
AFNI uses 32 bit ints as array indexes, which means that no array can have more than 2 G entries. This is not a 2 GB llimit, though, since each "entry" (voxel value) could have more than one byte. The upper limit on memory would be imposed by a couple of things. The first would be the operating system, but I don't think IRIX has a 2 GB upper limit (but that may be configurable?). The second thing is pointer size. Since AFNI uses 32 bit pointers for memory access, it would be limited to using 4 GB of memory at once.

It might be possible to compile AFNI to use 64 bit pointers. I've not tried this, since I don't use a 64 bit computer system much. I suspect there might be a few problems in places, but probably not too hard to overcome.

If you are processing a lot of datasets, but each processing thread is less than 2 GB, then on a 64 bit system such as IRIX, you could simply run multiple processes at once (e.g., several 3dDeconvolve scripts).

I don't have such high end systems, so can't go on much further. -- bob cox
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Subject Author Posted

afni memory allocation

Timothy_Souza January 10, 2003 05:46PM

Re: afni memory allocation

bob cox January 10, 2003 06:20PM