Hello, I have installed MPICH 3.2 on a CENTOS 6 machine with the following configuration options: setenv CC /usr/bin/gcc setenv FC /usr/bin/gfortran setenv CXX /usr/bin/c++ setenv INS_DIR /opt/mpich_gfc ../mpich-3.2/configure --prefix=$INS_DIR --with-device=ch3:nemesis |& tee configure.log make --jobs 4 |& tee make.log make install and the installation appeared to have completed without error (see the attached configure.log and make.log files). However, when I attempt to run a simple hello_world FORTRAN 90 program, I get the following error: hyp22 rbaurle 2293> mpirun -n 3 a.out < hello.inp a.out: symbol lookup error: /opt/mpich/lib/libmpifort.so.12: undefined symbol: MPI_UNWEIGHTED If I repeat the installation, but change the Fortran90 compiler from GFORTRAN to the Lahey 8.1 compiler, i.e.: setenv FC /opt/lahey-64/bin/lf95 then the hello_world program runs just fine. Do you have any idea what might be going on here? I should also mention that the same error appears if I install MPICH 3.1.3. Thanks, Rob _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss