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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ptaylor
December 03, 2022 08:16AM
Hi-

You can check the voxelsize and matrix dimensions of one or more datasets with: 
3dinfo -ad3 -n4 -prefix DSET_OR_LIST_OF_DSETS
You can also ask if two datasets have the same grid (a more detailed constraint) with: 
3dinfo -same_all_grid LIST_OF_DSETS

Calculations across datasets often require having the same grid. There are multiple ways to put a dataset onto another grid, but it is correct to know what your expectations are for it and how it got to its current place---you want to use a grid transformation that is appropriate for the data. I guess the first question is, why don't the datasets in your 3dttest++ command sit on the same grid? How were they processed? Are they actually in the same "space" (e.g., they were all aligned to a single template, and if you view them in the AFNI GUI, they overlap correctly), but have a different grid?

--pt
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ttest problem Attachments

BogengSong December 03, 2022 04:07AM

Re: ttest problem

ptaylor December 03, 2022 08:16AM