# Mpirun: cannot start gmx\_mpi on n0 (o): No such file or directory

**URL:** <https://gromacs.bioexcel.eu/t/mpirun-cannot-start-gmx-mpi-on-n0-o-no-such-file-or-directory/1346>\
**Category:** User discussions\
**Created:** [December 28, 2020, 12:51pm UTC](https://gromacs.bioexcel.eu/t/mpirun-cannot-start-gmx-mpi-on-n0-o-no-such-file-or-directory/1346 "2020-12-28T12:51:11Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![sam](https://avatars.discourse-cdn.com/v4/letter/s/5f9b8f/32.png) [@sam](https://gromacs.bioexcel.eu/u/sam)\
**Post date:** [December 28, 2020, 12:51pm UTC](https://gromacs.bioexcel.eu/t/mpirun-cannot-start-gmx-mpi-on-n0-o-no-such-file-or-directory/1346/1 "2020-12-28T12:51:11Z")

</div>

GROMACS version:2020.4  
i’m trying to run this command

> mpirun -np 4 gmx\_mpi mdrun -s remd\_.tpr -multi 36 -replex 500 -deffnm remd\_ -v \>& md.out &

I got

> Mpirun: cannot start gmx\_mpi on n0 (o): No such file or directory

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<div class="post-metadata">

**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:** [December 29, 2020, 2:50am UTC](https://gromacs.bioexcel.eu/t/mpirun-cannot-start-gmx-mpi-on-n0-o-no-such-file-or-directory/1346/2 "2020-12-29T02:50:10Z")

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You need to configure your environment to know where the `gmx_mpi` binary is.

> **[Installation guide — GROMACS 2020.4 documentation](https://manual.gromacs.org/current/install-guide/index.html#getting-access-to-gromacs-after-installation)**

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<div class="post-metadata">

**Author:** ![sam](https://avatars.discourse-cdn.com/v4/letter/s/5f9b8f/32.png) [@sam](https://gromacs.bioexcel.eu/u/sam)\
**Post date:** [December 29, 2020, 10:22am UTC](https://gromacs.bioexcel.eu/t/mpirun-cannot-start-gmx-mpi-on-n0-o-no-such-file-or-directory/1346/3 "2020-12-29T10:22:30Z")

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thanks for replying … the error changed to become

> [proxy:0:0@user] HYDU\_create\_process (utils/launch/launch.c:74): execvp error on file gmx\_mpi (No such file or directory)  
> [proxy:0:0@user] HYDU\_create\_process (utils/launch/launch.c:74): execvp error on file gmx\_mpi (No such file or directory)  
> [proxy:0:0@user] HYDU\_create\_process (utils/launch/launch.c:74): execvp error on file gmx\_mpi (No such file or directory)  
> [proxy:0:0@user] HYDU\_create\_process (utils/launch/launch.c:74): execvp error on file gmx\_mpi (No such file or directory)

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<div class="post-metadata">

**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:** [December 29, 2020, 1:38pm UTC](https://gromacs.bioexcel.eu/t/mpirun-cannot-start-gmx-mpi-on-n0-o-no-such-file-or-directory/1346/4 "2020-12-29T13:38:33Z")

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That’s the same problem, just printed multiple times by the different MPI processes.

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<div class="post-metadata">

**Author:** ![sam](https://avatars.discourse-cdn.com/v4/letter/s/5f9b8f/32.png) [@sam](https://gromacs.bioexcel.eu/u/sam)\
**Post date:** [December 29, 2020, 4:43pm UTC](https://gromacs.bioexcel.eu/t/mpirun-cannot-start-gmx-mpi-on-n0-o-no-such-file-or-directory/1346/5 "2020-12-29T16:43:22Z")

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I did the following

```
cmake .. -DGMX_MPI=ON 

```

and got

```
CMake Warning at cmake/gmxManageSharedLibraries.cmake:74 (message):
Both BUILD_SHARED_LIBS and GMX_BUILD_MDRUN_ONLY are set. Generally, an
mdrun-only build should prefer to use static libraries, which is the
default if you make a fresh build tree. You may be re-using an old build
tree, and so may wish to set BUILD_SHARED_LIBS=off yourself.
Call Stack (most recent call first):
CMakeLists.txt:456 (include)
-- Configuring done
-- Generating done
-- Build files have been written to: /home/user/Desktop/gromacs-2020.4

```

and I tried to get the path of `gmx_mpi` by

```
whereis gmx_mpi

```

got

```
gmx_mpi:

```

also I check `echo $GMXDATA`

and got `/usr/local/gromacs/share/gromacs`

and `gmx --version` worked well

Does i have `gmx_mpi` ?

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<div class="post-metadata">

**Author:** ![sam](https://avatars.discourse-cdn.com/v4/letter/s/5f9b8f/32.png) [@sam](https://gromacs.bioexcel.eu/u/sam)\
**Post date:** [December 30, 2020, 12:00am UTC](https://gromacs.bioexcel.eu/t/mpirun-cannot-start-gmx-mpi-on-n0-o-no-such-file-or-directory/1346/6 "2020-12-30T00:00:20Z")

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i’m trying a lot to figure out the problem and searched more … i exchanged the command to become using

> mdrun\_mpi instead of gmx\_mpi mdrun

does that right ?

i tried to run it

> mpirun -np 4 mdrun\_mpi -s remd\_.tpr -multi 20 -replex 500 -deffnm remd\_ -v \>& md.out &

and got

> The number of ranks (1) is not a multiple of the number of simulations (20)

i have 20 temperatures file … … cpu 6 cores

and got in

> md.out file

> MPI\_ABORT was invoked on rank 0 in communicator MPI\_COMM\_WORLD  
> with errorcode 1.  
> NOTE: invoking MPI\_ABORT causes Open MPI to kill all MPI processes.  
> You may or may not see output from other processes, depending on  
> exactly when Open MPI kills them.

thanks for your time and help really