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_123@yahoo.com>
To: users@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



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