Dear All
Thank you Brock and Terry for your comments. I did now install manually openmpi. Now openmpi works properly. I can compile and run my programs.It is so wonderful now. The result is now the same as when I run it in Linux cluster and on my dual processor Laptop. When I run : mpirun -np 4 ./test (test being the exe file coming form my the compiled fortran program). The program still give a result based on 4 processor. How can this be true while I have only two processor in my laptop. Can any one comment on this ? Regards yacob ----- Original Message ---- From: yacob sen <yacob_...@yahoo.com> To: us...@open-mpi.org Sent: Monday, April 7, 2008 5:08:39 PM Subject: An error occurred in MPI_comm_size Dear All, I have just installed openmpi/mpich in ubuntu 7.10 in my linux machine which has a dual processor. I compiled my fortran program as follows: mpif90 add.f90 -o add_n I, however, forced to copy "mpif.h" library in my working directory where i run my program and also I inserted an additional line inside the file "/etc/openmpi/openmpi-mca-params.conf", the following : btl=^openib. I have then run the program as: mpirun -np 2 ./add_n (here I use 2 processor as my dual laptop has two processor) What I got is the following error message : [geosl063:13781] *** An error occurred in MPI_comm_size [geosl063:13780] *** An error occurred in MPI_comm_size [geosl063:13780] *** on communicator MPI_COMM_WORLD [geosl063:13780] *** MPI_ERR_COMM: invalid communicator [geosl063:13780] *** MPI_ERRORS_ARE_FATAL (goodbye) [geosl063:13781] *** on communicator MPI_COMM_WORLD [geosl063:13781] *** MPI_ERR_COMM: invalid communicator I used MPI commands to program my fortran code. The program has been running in a linux cluster. The point here is to develop my parallel program in my linux laptop before I go and run it in a Linux cluster. Any comments. I appreciate any comments Thank you so much Yacob You rock. That's why Blockbuster's offering you one month of Blockbuster Total Access, No Cost. ____________________________________________________________________________________ You rock. That's why Blockbuster's offering you one month of Blockbuster Total Access, No Cost. http://tc.deals.yahoo.com/tc/blockbuster/text5.com