Re: [AMBER-Developers] constants and constants.f

From: B. Lachele Foley <>
Date: Mon, 11 Oct 2010 18:41:27 +0000

I'm not claiming to be elite, but I am a big fan of being exceedingly picky about these things. So, I vote to make them all the same and clean up the tests. In fact, go to NIST and make sure they are the official, most recent, umpteen-decimal versions. I also vote to make all the functions use the same constants from one central location unless there is some very good reason a certain function needs it to be different.

On that note, and showing my ignorance, is there a document somewhere that lists all the units and values used in Amber, including, for example, the amusing choice of unit for charge? If not, that's my next manual suggestion.

From: Jason Swails []
Sent: Monday, October 11, 2010 2:09 PM
To: AMBER Developers Mailing List
Subject: [AMBER-Developers] constants and constants.f


In the course of my work I've been rummaging through runmd.f, force.f, and
ew_force.f, and figured that while I was there I'd attempt some cleanups,
like adding intent to variables and consolidating the use of constants.
Particularly, Boltzmann's constant was defined separately in many different
subroutines, so I changed it to KB from the constants module (as I think it
should be). However, the values used in the various subroutines differed
slightly from the value in constants.f, so now a very large number of tests
are failing due to inconsistencies in the last reported decimal place for
temperatures and kinetic energies in several places.

My question is should I purge those changes or keep them and update the
tests? Obviously, I'd have to pick through the tests and make sure that the
changes are benign and caused by my changes to the value of boltz2, but I
think it's worth consolidating the use of KB so the same value is used
throughout the source code that originates from the same declaration.
However, I thought I'd poll the Amber elite rather than run away with my
ideas and assumptions.


Jason M. Swails
Quantum Theory Project,
University of Florida
Ph.D. Graduate Student
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Received on Mon Oct 11 2010 - 12:00:03 PDT
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