From: John Dood <john.dood.hope.edu>
Date: Mon, 6 Jul 2015 09:18:47 -0400

Hi all,

I am simulating large salt crystals and am exploring the effect that nfft
has on the potential energy (considering the importance of electrostatics
in salt). I initially ran into trouble when I ran a simulation with an nfft
greater than 2048 getting the error message:

 parameter nfft1: (grid size) has value 4000
 This is outside the legal range
 Lower limit: 6 Upper limit: 2048
 The limits may be adjustable; search in the .h files

So I ran a simulation with half the nfft and got the following error

nfft1-3 too large! check on MAXNFFT in ew_bspline.f

and found that maxnfft has a value of 500. After increasing the value of
maxnfft to 2048 as discussed in http://archive.ambermd.org/200811/0285.html
and http://archive.ambermd.org/201006/0195.html I found that I could get
nfft=800 to work but not nfft=2000 (the program ends with a segfault)

I have a couple of questions. Why is there a different limit in
ew_setup.F90 and ew_legal.h? Why does a simulation of 800 work and not a
simulation with 2000? If anyone has experience with this kind of issue I
would love to hear your take on it.

I am running Amber 14 (Amber 14, AmberTools 14) on a CentOS 5.6 host with
Intel Compiler Suite v12


John Dood
AMBER mailing list
Received on Mon Jul 06 2015 - 06:30:03 PDT
Custom Search