# How can i get the exchange probabiltiy? **URL:** \ **Category:** User discussions\ **Created:** [July 13, 2021, 8:11am UTC](https://gromacs.bioexcel.eu/t/how-can-i-get-the-exchange-probabiltiy/2500 "2021-07-13T08:11:41Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![sam](https://avatars.discourse-cdn.com/v4/letter/s/5f9b8f/32.png) [@sam](https://gromacs.bioexcel.eu/u/sam)\ **Post date:** [July 13, 2021, 8:11am UTC](https://gromacs.bioexcel.eu/t/how-can-i-get-the-exchange-probabiltiy/2500/1 "2021-07-13T08:11:42Z")
GROMACS version:2020.4 i installed gromacs and need to know the exchange probability but didn’t got any file holding this name and got only md.log which also didn’t contain exchange probability this the command i run for 36 temperatures > for i in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 > do > gmx grompp -f nvt\_$i.mdp -c em.gro -p topol.top -o remd\_$i.tpr > done > gmx mdrun -ntmpi 18 -ntomp 2 -dds 0.998 -s remd\_$i.tpr does exchange probability appears after run finish or during the run ? ---
**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:** [July 13, 2021, 12:28pm UTC](https://gromacs.bioexcel.eu/t/how-can-i-get-the-exchange-probabiltiy/2500/2 "2021-07-13T12:28:24Z")
Are you intending to run replica exchange MD? Your commands above loop over `grompp` then run a single `mdrun` process. You do not run REMD simulations in a loop, there is specific syntax (see the manual and online tutorials). ---
**Author:** ![sam](https://avatars.discourse-cdn.com/v4/letter/s/5f9b8f/32.png) [@sam](https://gromacs.bioexcel.eu/u/sam)\ **Post date:** [July 13, 2021, 12:42pm UTC](https://gromacs.bioexcel.eu/t/how-can-i-get-the-exchange-probabiltiy/2500/3 "2021-07-13T12:42:14Z")
Excuse me do you mean I need to write the single command in the loop … and where can I find the tutorial for this point. Thanks a lot for replying ---
**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:** [July 13, 2021, 12:53pm UTC](https://gromacs.bioexcel.eu/t/how-can-i-get-the-exchange-probabiltiy/2500/4 "2021-07-13T12:53:26Z")
[https://www.gromacs.org/Documentation\_of\_outdated\_versions/Tutorials/GROMACS\_USA\_Workshop\_and\_Conference\_2013/An\_introduction\_to\_replica\_exchange\_simulations%3A\_Mark\_Abraham%2C\_Session\_1B](https://www.gromacs.org/Documentation_of_outdated_versions/Tutorials/GROMACS_USA_Workshop_and_Conference_2013/An_introduction_to_replica_exchange_simulations%3A_Mark_Abraham%2C_Session_1B) ---
**Author:** ![sam](https://avatars.discourse-cdn.com/v4/letter/s/5f9b8f/32.png) [@sam](https://gromacs.bioexcel.eu/u/sam)\ **Post date:** [July 16, 2021, 1:44pm UTC](https://gromacs.bioexcel.eu/t/how-can-i-get-the-exchange-probabiltiy/2500/5 "2021-07-16T13:44:11Z")
thanks a lot for helping . i followed the tutorial as i have now 6 temperatures … i created folder called stage2 inside it i created 6 folders each one called sim1 sim2 … sim6 inside each folder sim.mdp with the temperature and sim.tpr i run this command > ## mpirun -np 6 gmx\_mpi mdrun -ntomp 12 -v -multidir sim[123456] -replex 100 but got gmx\_mpi: error while loading shared libraries: libcufft.so.9.1: cannot open shared object file: No such file or directory gmx\_mpi: error while loading shared libraries: libcufft.so.9.1: cannot open shared object file: No such file or directory gmx\_mpi: error while loading shared libraries: libcufft.so.9.1: cannot open shared object file: No such file or directory gmx\_mpi: error while loading shared libraries: libcufft.so.9.1: cannot open shared object file: No such file or directory gmx\_mpi: error while loading shared libraries: libcufft.so.9.1: cannot open shared object file: No such file or directory > > It seems that [at least] one of the processes that was started with > mpirun did not invoke MPI\_INIT before quitting (it is possible that > more than one process did not invoke MPI\_INIT – mpirun was only > notified of the first one, which was on node n0). > > mpirun can _only_ be used with MPI programs (i.e., programs that > invoke MPI\_INIT and MPI\_FINALIZE). You can use the “lamexec” program > to run non-MPI programs over the lambooted nodes. ---
**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:** [July 20, 2021, 1:15pm UTC](https://gromacs.bioexcel.eu/t/how-can-i-get-the-exchange-probabiltiy/2500/6 "2021-07-20T13:15:41Z")
You need to configure your environment to find the CUDA libraries.