Re: [AMBER] cpptraj density routine

From: Daniel Roe <>
Date: Wed, 22 Jan 2014 14:17:23 -0700

Hi, sorry for the delay in replying.

Unfortunately the 'density' action currently does not use the internal data
set/data file framework, so options like changing the precision or writing
in a different format are not yet supported. There is planned support for
this in the next release.

I think in the meantime the only way to get higher precision will be to
modify the source code yourself to increase the precision and re-compile
(of course if you do this keep a non-modified copy of the file just in
case). You will have to edit Action_Density.cpp; look for 'output_.Printf('
statements. Let me know if you have any more questions.

Hope this helps,


On Wed, Jan 15, 2014 at 8:01 AM, Dickson, Callum J <> wrote:

> Hi,
> I have been using the cpptraj density routine to calculate the charge
> density of my system along the z-axis. I was wondering whether I could
> obtain the output with a higher number of decimal places. I've tried the
> 'precision' keyword for cpptraj but so far without success.
> My cpptraj input file is:
> trajin
> density out charge.tmp charge delta 0.25 z "*"
> I'd ideally like 8 decimal places (the same number of decimal places used
> for charges in the prmtop). I've tried:
> trajin
> density out charge.tmp charge delta 0.25 z "*"
> precision charge.tmp 12 8
> However I'm not sure if cpptraj recognises the precision keyword in this
> instance. Any help would be appreciated.
> Kind regards,
> Callum
> _______________________________________________
> AMBER mailing list

Daniel R. Roe, PhD
Department of Medicinal Chemistry
University of Utah
30 South 2000 East, Room 201
Salt Lake City, UT 84112-5820
(801) 587-9652
(801) 585-6208 (Fax)
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Received on Wed Jan 22 2014 - 13:30:02 PST
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