# Topology include file "...forcefield.itp" not found **URL:** \ **Category:** User discussions\ **Created:** [May 21, 2020, 9:05am UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164 "2020-05-21T09:05:18Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![csangang](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/32.png) [@csangang](https://gromacs.bioexcel.eu/u/csangang)\ **Post date:** [May 21, 2020, 9:05am UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164/1 "2020-05-21T09:05:18Z")
GROMACS version: 2020 GROMACS modification: No Here post your question Hi, I am getting this fatal error whenever I try to generate my tpr file to run energy minimization. From my understanding, it’s telling me it can’t read/find the forcefield directory? So I tried moving it to a different folder but I still can’t get past it. Appreciate any suggestions/advice. Thank you. Cynthia ---
**Author:** ![Teslim](https://avatars.discourse-cdn.com/v4/letter/t/f1d935/32.png) [@Teslim](https://gromacs.bioexcel.eu/u/Teslim)\ **Post date:** [May 21, 2020, 3:01pm UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164/2 "2020-05-21T15:01:17Z")
for oplssa, the forcefield file is usually in the oplsaa folder in the shared library. see the below the format for calling in the .top file. #include “oplsaa.ff/forcefield.itp” PS: if you generate your .top file using gmx pdb2gmx command, that shouldnt be a problem ---
**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\ **Post date:** [May 21, 2020, 3:13pm UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164/3 "2020-05-21T15:13:22Z")
Please provide the exact error message you received. ---
**Author:** ![csangang](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/32.png) [@csangang](https://gromacs.bioexcel.eu/u/csangang)\ **Post date:** [May 21, 2020, 7:09pm UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164/4 "2020-05-21T19:09:20Z")
The message reads: Fatal error: Topology include file “/home/cynthia/Documents/Graphene sheet/gromos54a7.ff/forcefield.itp” My working directory is ‘Graphene sheet’ where the ‘gromos54a7.ff’ forcefield folder is located which contains the ‘forcefield.itp’ file. My GROMACS is located in /usr/bin/gmx…could this be why? Does the forcefield have to read from the gmx directory? ---
**Author:** ![csangang](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/32.png) [@csangang](https://gromacs.bioexcel.eu/u/csangang)\ **Post date:** [May 21, 2020, 7:12pm UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164/5 "2020-05-21T19:12:08Z")
The message reads: Fatal error: Topology include file “/home/cynthia/Documents/Graphene sheet/gromos54a7.ff/forcefield.itp” My working directory is ‘Graphene sheet’ where the ‘gromos54a7.ff’ forcefield folder is located which contains the ‘forcefield.itp’ file. My GROMACS is located in /usr/bin/gmx…could this be why? Does the forcefield have to read from the gmx directory? ---
**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\ **Post date:** [May 21, 2020, 7:39pm UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164/6 "2020-05-21T19:39:32Z")
> [@csangang](#): > > The message reads: > > Fatal error: > Topology include file “/home/cynthia/Documents/Graphene sheet/gromos54a7.ff/forcefield.itp” I suspect there is more to the error message. A file location is not a fatal error. Please provide the whole error. It could be there is a problem reading the file because you’re using spaces in your directory name, but that shouldn’t be an issue, I don’t think. > [@](#): > > My GROMACS is located in /usr/bin/gmx…could this be why? Does the forcefield have to read from the gmx directory? No, force field directories can be anywhere. ---
**Author:** ![Nandan](https://avatars.discourse-cdn.com/v4/letter/n/b19c9b/32.png) [@Nandan](https://gromacs.bioexcel.eu/u/Nandan)\ **Post date:** [October 9, 2020, 8:46am UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164/7 "2020-10-09T08:46:48Z")
In case anyone else comes across this looking for a solution, here is what worked for me. I’m new to Gromacs, but I ran into a similar issue. I resolved it by removed the first “/” in the include statement. ie. Having the line #include “/toppar/martini\_v2.2.itp” in my .top file resulted in the same fatal error you described, and this was fixed by replacing this include statement with #include “toppar/martini\_v2.2.itp” It seems like the file path in your include statement began with “/” as well. Your fatal error shows the file path as “/home/…”. ---
**Author:** ![Teslim](https://avatars.discourse-cdn.com/v4/letter/t/f1d935/32.png) [@Teslim](https://gromacs.bioexcel.eu/u/Teslim)\ **Post date:** [October 11, 2020, 11:55am UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164/8 "2020-10-11T11:55:21Z")
If you have the file martini\_v2.2.itp in folder toppar, there won’t be any error. Your current command will work if toppar is a folder that’s available in your pwd. / means steps into the following while …/ means take a step backward from this pwd. If you copy the file (martini\_v2.2.itp) to your pwd, you can replace the path with just #include “martini\_v2.2.itp” or go to where you have the file, type pwd and modify it as follows: #include “ **put-path-here** /martini\_v2.2.itp” ---
**Author:** ![muneeshwari](https://avatars.discourse-cdn.com/v4/letter/m/48db29/32.png) [@muneeshwari](https://gromacs.bioexcel.eu/u/muneeshwari)\ **Post date:** [October 15, 2020, 7:49am UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164/9 "2020-10-15T07:49:28Z")
Hello sir , I am new for molecular dynamics simulation. so, i have some doubt about running simulation using gromacs. whats is the optimum timestep for NVT and NPT running. if, 100ps running is enough for equilibration (100ps given in the gromacs tutorial). Thanking you ---
**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\ **Post date:** [October 15, 2020, 12:52pm UTC](https://gromacs.bioexcel.eu/t/topology-include-file-forcefield-itp-not-found/164/10 "2020-10-15T12:52:22Z")
“Time step” is the value of `dt` (the integration time step in the simulation), so that refers to something very specific. Be careful with terminology! As far as the time required to equilibrate, there is no real answer to this. You need to equilibrate for sufficient time that all the relevant thermodynamic properties have stabilized. For reasonably small, simple systems, this may be very quick, but for large, heterogeneous systems, it can take somewhat longer.