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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rick reynolds
March 02, 2009 04:53PM
Hi Arun,

Your constant and scale terms are very large. How big are your
TENT function betas?

While '-sconstr 2' contains 8.6 (standard GAM), '-sconstr 3'
does not contain 0.547. So the standard shape is not possible
to match. Note that some of the curves can peak over 100, so
scaling on the order of 1000 might be too much.

But nrand=500 might be a problem, too. I would suggest more
like 10000.

Consider running '1deval' to test possible outcomes. For
example assuming no time offset and a scalar of 1, this would
plot the curve of the standard "8.6, 0.547" model on a 0.1
second grid for 12 seconds:

1deval -num 120 -expr '(0.1*t)**8.6*exp(-t/5.47)' > ts.1D
1dplot ts.1D

Note that I multiplied the 0.1 factor out of the exponential
term...

- rick

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Subject Author Posted

3dNLfim problem

Arun March 02, 2009 12:28PM

Re: 3dNLfim problem

rick reynolds March 02, 2009 04:53PM

Re: 3dNLfim problem

Bob Cox March 03, 2009 08:40AM