[gmx-users] Tabulated Potentials

2013-06-13 Thread O'Neill, David
Hello Users, Recently I have been trying to implement the use of tabulated potentials in GROMACS to an system of argon atoms. I run a NVE simulation of 1000 argon atoms and then plot the potential energy from the output. ar.itp : [ defaults ] ; nbfunccomb-rule gen-pairs

[gmx-users] tabulated potentials and soft core free energy - this should not work ....

2012-06-27 Thread Michael Brunsteiner
Hi, i meant to perform a free energy calculation to get the chemical potential of water, and made a number of input files based on the excellent tutorial by Justin Lemkul. (Without thinking) I also tried using a tabulated potential for electrostatics with: coulombtype = User but it seems to

Re: [gmx-users] Tabulated potentials for dihedrals - regd

2012-06-07 Thread Mark Abraham
On 7/06/2012 4:33 AM, ramesh cheerla wrote: Dear Mark, Thank you for your reply, According to my understanding functional form of dihedral function type 9 is same as dihedral function type 1 i.e k(1 + cos(n (phi)- phis)) except the difference that function type 9

Re: [gmx-users] Tabulated potentials for dihedrals - regd

2012-06-07 Thread ramesh cheerla
Dear Mark, I am very Thankful to you for your valuable suggestion. On Thu, Jun 7, 2012 at 12:04 PM, Mark Abraham mark.abra...@anu.edu.auwrote: On 7/06/2012 4:33 AM, ramesh cheerla wrote: Dear Mark, Thank you for your reply, According to my understanding

Re: [gmx-users] Tabulated potentials for dihedrals - regd

2012-06-06 Thread ramesh cheerla
Dear Mark, Thank you for your reply, According to my understanding functional form of dihedral function type 9 is same as dihedral function type 1 i.e k(1 + cos(n (phi)- phis)) except the difference that function type 9 is used to handle the multiple potential

Re: [gmx-users] Tabulated potentials for dihedrals - regd

2012-06-04 Thread Mark Abraham
On 4/06/2012 3:46 AM, ramesh cheerla wrote: Dear Gromacs experts, I am planing to use tabulated potentials for dihedral functional form Summn over 'n' 0.5*K [ ( Cos n(phi-phi0)] , Here 1= n = 3 . I have three different K values (i.e K1,K2,K3 ) one for each

[gmx-users] Tabulated potentials for dihedrals - regd

2012-06-03 Thread ramesh cheerla
Dear Gromacs experts, I am planing to use tabulated potentials for dihedral functional form Summn over 'n' 0.5*K [ ( Cos n(phi-phi0)] , Here 1= n = 3 . I have three different K values (i.e K1,K2,K3 ) one for each 'n' value ( Here 'n' is multiplicity). I have

[gmx-users] tabulated potentials for dihedrals - regd

2012-05-18 Thread ramesh cheerla
Dear Gromacs users, I am using tabulated potentials for the dihedrals of my system, the dihedral function I am using is Summn over 'n' 0.5*K [ ( Cos n(phi-phi0)] , Here 1= n = 3 . The C-O-C-C dihedral of my system has three folds those are n= 1 , 2, 3 and three

[gmx-users] Tabulated potentials for the Dihedrals - regd

2012-05-16 Thread ramesh cheerla
Dear Gromacs users, I am using tabulated potentials for dihedrals of my system which is of form dih = (1/2)*K[COS n(phi-phi0)], Here n=3. I have generated table_d0.xvg by uniformly varying phi as 0.1 from -180 to 180 and calculated the numerical

[gmx-users] Tabulated potentials

2012-01-23 Thread Laura Leay
All, I'm simulating a very small system of methane using tabulated potentials. Charges are not modified and I'm using a cubic for values up to 0.19 nm and the normal 6-12 LJ potential after that (the form the cubic is such that the value and gradient at 0.19 nm is the same as for the 6-12 LJ).

[gmx-users] tabulated potentials

2011-05-03 Thread Sikandar Mashayak
Hi I want to try out different potentials using tabulated potential method. I am planning to specify sigma and epsilon such that C6 and C12 values will be 1.0 and in table.xvg file 6th and 7th columns will contain actual potential and force values, whereas columns 2-5 will be zero. As per

[gmx-users] tabulated potentials for non-bonded interactions

2011-05-02 Thread Sikandar Mashayak
Hi Is it possible to use use specified potentials only for vdw type non-bonded interactions while keeping usual PME,bonded, pairs interactions? When I specifiy User for vdwtype force in .mdp file, I am observing that mdrun expects table for bonded interactions also through -tableb option and by

[gmx-users] Tabulated potentials and normal nonbonded interaction at the same time

2010-09-15 Thread Thomas Schlesier
Dear Gromacs-User, i want to try to simulate an atomistic molecule with CG-solvent (uncharged). For the atomistic molecule i want to use the normal non-bonded interactions, but for the CG-solvent interaction with itself and the molecule i need a tabulated potential. So my question is, is that

Re: [gmx-users] Tabulated potentials and normal nonbonded interaction at the same time

2010-09-15 Thread Gareth Tribello
Hello I think what you need to do is use multiple tables. So you have one table for your CG-solvent interaction with itself and then another one for your CG-solvent (uncharged) interactions. (This second table would then just a tabulated version of the Lennard Jones interaction or whatever you

Re: [gmx-users] Tabulated potentials and normal nonbonded interaction at the same time

2010-09-15 Thread Mark Abraham
- Original Message - From: Gareth Tribello gareth.tribe...@gmail.com Date: Thursday, September 16, 2010 4:33 Subject: Re: [gmx-users] Tabulated potentials and normal nonbonded interaction at the same time To: Discussion list for GROMACS users gmx-users@gromacs.org Hello I think

Re: [gmx-users] Tabulated potentials and performance

2010-08-04 Thread João M . Damas
Hi guys, From what I've tested, it seems that performances decreases linearly with the amount of tables used, exactly the opposite of what Lanyuan has said. I've tested this for GROMACS 4.0.4 and from 1 to 190 tables. Near 190 tables, it seems that a threshold in performance starts to form, but

Re: [gmx-users] Tabulated potentials and performance

2010-07-20 Thread ms
On 19/07/10 23:18, Lanyuan Lu wrote: From our group's experience, there is a critical point for dramatic performance drop when one uses two many tables. The possible reason is that the size of tables exceeds the cache size. However, this only happens when the number of tables is beyond

[gmx-users] Tabulated potentials and performance

2010-07-19 Thread ms
Hi, Do you know where can I find some information on how using tabulated potential affects gmx performance, and how? I have to decide how to project a custom model but I don't want to calculate dozens of tables only to find that gmx grinds to a halt. thanks! M. -- gmx-users mailing list

Re: [gmx-users] Tabulated potentials and performance

2010-07-19 Thread Da-Wei Li
It will be very little from my experience. Remember that the dominate part is the non-bonded force calculation. dawei On Mon, Jul 19, 2010 at 12:22 PM, ms deviceran...@gmail.com wrote: Hi, Do you know where can I find some information on how using tabulated potential affects gmx performance,

Re: [gmx-users] Tabulated potentials and performance

2010-07-19 Thread ms
On 19/07/10 17:32, Da-Wei Li wrote: It will be very little from my experience. Remember that the dominate part is the non-bonded force calculation. Well, that's exactly what I tabulate. dawei On Mon, Jul 19, 2010 at 12:22 PM, msdeviceran...@gmail.com wrote: Hi, Do you know where can I

Re: [gmx-users] Tabulated potentials and performance

2010-07-19 Thread Da-Wei Li
I remember the manu states that it won't cost too much compared with standard potential function form. dawei On Mon, Jul 19, 2010 at 1:22 PM, ms deviceran...@gmail.com wrote: On 19/07/10 17:32, Da-Wei Li wrote: It will be very little from my experience. Remember that the dominate part is the

Re: [gmx-users] Tabulated potentials and performance

2010-07-19 Thread ms
On 19/07/10 18:32, Da-Wei Li wrote: I remember the manu states that it won't cost too much compared with standard potential function form. Well, I find in the manual exactly the opposite: Note that table lookup is significantly slower than computation of the most simple Lennard-Jones and

Re: [gmx-users] Tabulated potentials and performance

2010-07-19 Thread Lanyuan Lu
From our group's experience, there is a critical point for dramatic performance drop when one uses two many tables. The possible reason is that the size of tables exceeds the cache size. However, this only happens when the number of tables is beyond something like 50. The total table size for the

[gmx-users] Tabulated potentials

2010-04-20 Thread Martin Vartorelli
Hi Gromacs users, previously I've posted my situation with a simulation and I'm still confused: I have 3 groups of different atoms: A, B and C, and tabulated bonding and non-bonding potentials. The tabulated bonded potentials are specified in the files: table_b1.xvg table_a1.xvg table_a2.xvg

Re: [gmx-users] Tabulated potentials

2010-04-20 Thread Gareth Tribello
Hi I think this is what you need to do: (1) Ensure that the topol.top and index.ndx files are set up in the manner described on the wikki. (2) Put in the mdp file the following: energygrps = A B C energygrp_table = A C B B B C (3) Now create a set of files as follows table.xvg -

RE: [gmx-users] Tabulated potentials make newbies crazy

2009-12-01 Thread Berk Hess
Date: Tue, 1 Dec 2009 07:44:51 +1100 From: mark.abra...@anu.edu.au To: gmx-users@gromacs.org Subject: Re: [gmx-users] Tabulated potentials make newbies crazy ms wrote: Mark Abraham ha scritto: Sorry, I was a bit incomplete last night. Charge groups are the fundamental unit

Re: [gmx-users] Tabulated potentials make newbies crazy

2009-11-30 Thread ms
Mark Abraham ha scritto: Sorry, I was a bit incomplete last night. Charge groups are the fundamental unit for neighbour-searching (3.4.2) to construct lists of charge groups for nonbonded interactions, which determine lists of atom-atom interactions. However, the nonbonded interactions are

Re: [gmx-users] Tabulated potentials make newbies crazy

2009-11-30 Thread Mark Abraham
ms wrote: Mark Abraham ha scritto: Sorry, I was a bit incomplete last night. Charge groups are the fundamental unit for neighbour-searching (3.4.2) to construct lists of charge groups for nonbonded interactions, which determine lists of atom-atom interactions. However, the nonbonded

Re: [gmx-users] Tabulated potentials make newbies crazy

2009-11-29 Thread Justin A. Lemkul
ms wrote: snip Sorry to say I can't help with the larger problem, but I'd like to comment on this: The problem is that since I have a single molecule now, and the single molecule must be neutral, so it must be all a single charge group (Therefore we have to keep groups of atoms with total

[gmx-users] Tabulated potentials make newbies crazy

2009-11-27 Thread ms
Hi, I am really having a hard time figuring out how to use tabulated potentials correctly. In general, the information on how to use tables is sparse and scattered in several points of the manual (ch.5, ch.7, ch.6.7...) -I hope to write a short howto in the wiki once I get this working, but now

RE: [gmx-users] tabulated potentials and pairs

2008-07-29 Thread Berk Hess
: [EMAIL PROTECTED] To: gmx-users@gromacs.org Subject: [gmx-users] tabulated potentials and pairs Dear all, I simulate a protein in water, and use AMBER03 parameters plus a tabulated potential for the Coulomb interactions. Next to the table.xvg file that i provide, mdrun seems to require