AMBER Archive (2008)

Subject: RE: AMBER: Using AMBER forces

From: Ross Walker (
Date: Tue Jun 24 2008 - 13:19:13 CDT

Hi Steven,

> Thanks for your reply. I just thought I'd point out that a while ago I
> tried obtaining the forces just by using the debugf options, but they
> don't play nicely with QM/MM:

Ah ha, now I remember. However, I think that was referring to the dumpfrc
option rather than the actual debugf option - that is testing against
numerical derivatives definitely works (although perhaps only in serial)
since I have used it several times to check that the analytical gradients
are coming out correctly so what I suggested about trying do_debugf=1 and
atomn=1,2,3... should work as a way for you to access the force array via
two different methods, with your write statement and with the info the
debugf prints to the output file, so that you can check that they match

If you are having problems here please send me your input files and I can
try it out myself.

All the best

|\oss Walker

| Assistant Research Professor |
| San Diego Supercomputer Center |
| Tel: +1 858 822 0854 | EMail:- |
| | PGP Key available on request |

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