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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August 27, 2014 01:01PM
> When it tells me to save my path matrices at the end, it gives me 3 options (with a lag of 1, 2, and 3).

Did you specify a model with 3 lags? With FMRI data, a log of 1 is probably good enough.

> Lapack routine dgesv: system is exactly singular: U[1,1] = 0

With 3 regions, the upper bound for the number of paths is 3. In your case, the degrees of freedom would be 0, and it seems the system is singular, which means insoluble. When you see the following choice:

Numerical scheme (0: Iterative; 1: Direct)?

Choose 1 (Direct), and see if that helps.

Gang
Subject Author Posted

Effective connectivity using 1dSEM

O.M. August 25, 2014 02:19PM

Re: Effective connectivity using 1dSEM

gang August 25, 2014 03:42PM

Re: Effective connectivity using 1dSEM

O.M. August 25, 2014 05:45PM

Re: Effective connectivity using 1dSEM

O.M. August 26, 2014 10:52AM

Re: Effective connectivity using 1dSEM

gang August 27, 2014 09:46AM

Re: Effective connectivity using 1dSEM

O.M. August 27, 2014 11:20AM

Re: Effective connectivity using 1dSEM

gang August 27, 2014 01:01PM

Re: Effective connectivity using 1dSEM

O.M. August 27, 2014 01:15PM

Re: Effective connectivity using 1dSEM

O.M. August 27, 2014 12:22PM