# PETSc not detected on cluster with mpirun = mpiexec **URL:** \ **Category:** FreeFEM installation\ **Created:** [February 26, 2021, 4:41pm UTC](https://community.freefem.org/t/petsc-not-detected-on-cluster-with-mpirun-mpiexec/829 "2021-02-26T16:41:12Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![zcwang6](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/zcwang6/32/371_2.png) [@zcwang6](https://community.freefem.org/u/zcwang6)\ **Post date:** [February 26, 2021, 4:41pm UTC](https://community.freefem.org/t/petsc-not-detected-on-cluster-with-mpirun-mpiexec/829/1 "2021-02-26T16:41:12Z")
Hey there, since the DM plex features requires FreeFem higher than 4.5; I tired to reinstall the FreeFem++ on my school’s cluster; The 4.5 version installation is good; But when I change it to 4.8 version, the PETSc can not be detected; The PETSc is installed correctly; From the config.log file, it seems like my MPI also can not be detected; I have no idea why 4.5 is working but 4.8 is not; I am putting the config.log file for your information here; Thx.[config.log](https://community.freefem.org/uploads/short-url/tszH70PnlCIFHAcqvPZe8OGaVF1.log) (430.2 KB) ---
**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\ **Post date:** [February 26, 2021, 5:15pm UTC](https://community.freefem.org/t/petsc-not-detected-on-cluster-with-mpirun-mpiexec/829/2 "2021-02-26T17:15:30Z")
This is not related to PETSc, but FreeFEM configure which doesn’t detect your MPI. What happens if you don’t use the flag `MPIRUN=mpiexec` in your command line? ---
**Author:** ![zcwang6](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/zcwang6/32/371_2.png) [@zcwang6](https://community.freefem.org/u/zcwang6)\ **Post date:** [February 26, 2021, 6:06pm UTC](https://community.freefem.org/t/petsc-not-detected-on-cluster-with-mpirun-mpiexec/829/3 "2021-02-26T18:06:48Z")
The same thing happened if I am not using it; ---
**Author:** ![zcwang6](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/zcwang6/32/371_2.png) [@zcwang6](https://community.freefem.org/u/zcwang6)\ **Post date:** [February 26, 2021, 6:12pm UTC](https://community.freefem.org/t/petsc-not-detected-on-cluster-with-mpirun-mpiexec/829/4 "2021-02-26T18:12:19Z")
wait for second; should I re run ./configure --enable-download --enable-optim --prefix=/home1/wangz6/ instead of ./reconfigure without MPIRUN = mpiexec ? ---
**Author:** ![zcwang6](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/zcwang6/32/371_2.png) [@zcwang6](https://community.freefem.org/u/zcwang6)\ **Post date:** [February 26, 2021, 6:18pm UTC](https://community.freefem.org/t/petsc-not-detected-on-cluster-with-mpirun-mpiexec/829/5 "2021-02-26T18:18:50Z")
without MPIRUN = mpiexec the MPI can be detected, but PETSc still not. ---
**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\ **Post date:** [February 26, 2021, 7:34pm UTC](https://community.freefem.org/t/petsc-not-detected-on-cluster-with-mpirun-mpiexec/829/6 "2021-02-26T19:34:28Z")
> without MPIRUN = mpiexec the MPI can be detected, but PETSc still not. Please send the `config.log`. ---
**Author:** ![zcwang6](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/zcwang6/32/371_2.png) [@zcwang6](https://community.freefem.org/u/zcwang6)\ **Post date:** [February 26, 2021, 7:51pm UTC](https://community.freefem.org/t/petsc-not-detected-on-cluster-with-mpirun-mpiexec/829/7 "2021-02-26T19:51:29Z")
I think I find out the problem, I add the MPIRUN = mpiexec on the .bash\_profile; which is ok with 4.5 version; But with 4.8, freefem can not detect the mpi for me; So with ./configure I deleted that MPIRUN = mpiexec, use it in the ./reconfigure stage; Now the FreeFem can find the mpi and petsc together; I am not sure if this is the reason; Here is the new config.log file;[config.log](https://community.freefem.org/uploads/short-url/9UKc0DVaup4mbs2yoZTwdlgMjys.log) (391.6 KB) ---
**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\ **Post date:** [February 26, 2021, 8:03pm UTC](https://community.freefem.org/t/petsc-not-detected-on-cluster-with-mpirun-mpiexec/829/8 "2021-02-26T20:03:03Z")
That is the problem, because that variable is used by FreeFEM `./configure` and it looks like it is messing things up on your machine. ---
**Author:** ![zcwang6](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/zcwang6/32/371_2.png) [@zcwang6](https://community.freefem.org/u/zcwang6)\ **Post date:** [February 26, 2021, 8:09pm UTC](https://community.freefem.org/t/petsc-not-detected-on-cluster-with-mpirun-mpiexec/829/9 "2021-02-26T20:09:50Z")
After this correction, 4.8 is installed correctly; Thanks for your quick replay and suggestions. Thx.