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

History of AFNI updates  

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June 18, 2004 01:33PM
When you use waver to create tent functions with a dt != 1,
it appears that the full tent function is computed and then
it is sampled every dt points starting at 0.

If dt is non-integer, then a linear interpolation of the
two points surrounding each sample location is performed.

Unless, dt goes evenly into the tent half-width (denominator of
tent function), then the output isn't a tent.

Here is an example with a dt of 1:
waver -dt 1.0 -EXPR 'tent((t-5)/5)' -peak 0 -tstim 0
0 + *
0.2
0.4 +
0.6 *
0.8 +
1
0.8 + *
0.6
0.4 +
0.2 *
0 +

the '+' shows the tent you would get with a dt of 2 (0, .4, .8, .8, .4, 0) and
the '*' show the tent you would get with a dt of 3 (0, .6, .8, .2)

John

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Posted to Phorum via PhorumMail
Subject Author Posted

waver question (another one)

John Ostuni June 18, 2004 01:33PM

Re: waver question (another one)

Gang Chen June 18, 2004 02:03PM

Re: waver question (another one)

John Ostuni June 18, 2004 02:50PM

Re: waver question (another one)

Ziad S. Saad June 18, 2004 03:28PM