amber-developers: leap and frcmod

From: Guanglei Cui <>
Date: Fri, 23 Sep 2005 07:47:00 -0700


I found out something peculiar about leap reading IMPR from frcmod. It
seems this hasn't been reported in bugfixes of amber8. If an improper
torsion is defined with a PK like XXX.0 (XXX is an integer), then leap
will dump a warning message:

WARNING: expected Improper Torsoin PK>0 (0.00000)
Here is the Improper Torsion line in question:
na na c2 na 10.0 180.0 2.

If the fraction part is changed to any nonzero number, leap is happy.
This problem is present in amber9 too. And I noticed in parm99.dat,
there are quite a few torsions defined with a PK of 1.0. I haven't
tested if those could be potential problems.

Received on Wed Apr 05 2006 - 23:49:52 PDT
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