Re: [AMBER-Developers] 1-4 Duplicate NB flagging when k atom index is one

From: Mark Williamson <>
Date: Thu, 28 May 2009 00:17:15 +0100

Dear All,

Thank you all for the comments and advice on this. I had initially
looked (for a while) into using IEEE 754 to place a sign on the integer
zero, but there seemed to be a inconsistent approach to formatted
negative zero printing in current compilers.

In the end, I just reversed the four integers that make up the torsion
index so that chamber would never write a negative zero on k:

Hence a problematic torsion:

9 6 -0 18 1

would be reversed and written to the prmtop as be:

18 0 -6 9 1

Thanks to Dave Case, Gustavo, Wei and Ross for discussions on this; this
modification has been added to chamber in the amber11 tree.



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Received on Thu May 28 2009 - 01:13:29 PDT
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