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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Hyuntaek
June 20, 2018 11:06AM
Hey Taylor,

Thank you for your answer.

Could you explain more specifically about "powers of 2 combined with powers of 3 and 5 (no more than 3^3 and 5^5, though)"..? Does this mean that 3dDFT adds 8 zero-paddings consisting of 3 and 5? Does zero-padding affect the magnitudes and phases of the DFT?

After performing DFT, I calculated the phases and amplitudes at specific frequencies (e.g. in my experiment, the stimulus has a periodicity at frequency 8). For example, I calculate the phase using the following command.

3dcalc -prefix $output_dir/pb08.${subj}_${hemi}.${hemi}.r{$r}.DFTPHA -cx2r PHASE -a $output_dir/pb07.${subj}_${hemi}.${hemi}.r{$r}.DFT.niml.dset'[8]' -expr "a"

Thanks!
Taek
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Subject Author Posted

3dDFT question

Hyuntaek June 19, 2018 04:07PM

Re: 3dDFT question

ptaylor June 20, 2018 08:15AM

Re: 3dDFT question

Hyuntaek June 20, 2018 11:06AM

Re: 3dDFT question

ptaylor June 21, 2018 07:29AM

Re: 3dDFT question

Hyuntaek June 21, 2018 05:27PM

Re: 3dDFT question

ptaylor July 04, 2018 02:33PM

Re: 3dDFT question

Hyuntaek July 05, 2018 03:13PM