AMBER Archive (2002)

Subject: SHAKE troubles

From: Arvid Soederhaell (arvid_at_fmp-berlin.de)
Date: Wed May 29 2002 - 05:07:17 CDT

Dear all,
I have some problems with SHAKE that I do not understand. I get the error
message

     COORDINATE RESETTING CANNOT BE ACCOMPLISHED,
     DEVIATION IS TOO LARGE
     NITER, NIT, LL, I AND J ARE : 0 0 1963 3195 3196

no matter what i do???!!! The error message comes from the shake.f
subprogram. The message implyes that i take a too long timestep, but even
a timestep of 0.5 fs is too long! (Normally one should be able to use a 2
fs timestep.) The simulation is stable if i turn off SHAKE and use a
0.2 fs timestep. The temperature in the simulation never exceeds 350 K.

Any suggestions to what could be the problem?

(The system is a DPPC lipid membrane with TIP3 water, and I use amber6)

Arvid