https://community.intel.com/t5/Intel-MPI-Library/Fatal-error-in-MPI-Comm-rank/m-p/783692#M437 Hi Jeffrey,<BR /><BR />Could you show me your compilation command line? Do you use Intel Fortran compiler? How do you run the application?<BR /><BR />Regards!<BR /> Dmitry<BR /> Mon, 14 Mar 2011 13:19:32 GMT Dmitry_K_Intel2 2011-03-14T13:19:32Z https://community.intel.com/t5/Intel-MPI-Library/Fatal-error-in-MPI-Comm-rank/m-p/783691#M436 What would cause this error?<BR /><BR />Fatal error in MPI_Comm_rank: Invalid communicator, error stack:<BR />MPI_Comm_rank(106): MPI_Comm_rank(comm=0x0, rank=0x7fffe44e7da4) failed<BR />MPI_Comm_rank(64).: Invalid communicator<BR /><BR />I am using IMPI 4.0.1.007.<BR /><BR />Its a hybrid OPenMP/MPI fortran90 code compiled with -i8 flag.<BR /><BR />Thanks. Sat, 12 Mar 2011 00:50:09 GMT https://community.intel.com/t5/Intel-MPI-Library/Fatal-error-in-MPI-Comm-rank/m-p/783691#M436 Jeffrey_Konz 2011-03-12T00:50:09Z https://community.intel.com/t5/Intel-MPI-Library/Fatal-error-in-MPI-Comm-rank/m-p/783692#M437 Hi Jeffrey,<BR /><BR />Could you show me your compilation command line? Do you use Intel Fortran compiler? How do you run the application?<BR /><BR />Regards!<BR /> Dmitry<BR /> Mon, 14 Mar 2011 13:19:32 GMT https://community.intel.com/t5/Intel-MPI-Library/Fatal-error-in-MPI-Comm-rank/m-p/783692#M437 Dmitry_K_Intel2 2011-03-14T13:19:32Z