you are missing “-host" before the IP-Address. Please use mpiexec —help, the web-documentation (http://www.mpich.org/static/docs/latest/), or stack overflow to answer questions like this in the future. This group is mainly for mpich-relatated questions, to report bugs or the like. Thanks, Lena On Apr 6, 2016, at 10:50 AM, יוסף אלון <[email protected]<mailto:[email protected]>> wrote: hii i am trying to execute an mpi command to specific node. but i am not succed. the command i am trying is: mpiexec 147.161.3.201 -n 1 hostname i try to excute the command from a c program by system("mpiexec 147.161.3.201 -n 1 hostname") -- בברכה, יוסף אלון 050-4916740 _______________________________________________ discuss mailing list [email protected]<mailto:[email protected]> To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss