Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

Subject: Re: [OMPI users] An error occurred in MPI_comm_size
From: Reuti (reuti_at_[hidden])
Date: 2008-04-08 06:38:00


Hi,

Am 08.04.2008 um 12:04 schrieb yacob sen:
> 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.

the Linux scheduler will just run these 4 processes as it would run
every other set of 4 processes, i.e. each one will get 50% of a core,
and you should see it in "top". It will of course not run faster, but
you can test whether your programm runs correct when using 4 or more
tasks.

-- Reuti

> Can any one comment on this ?
>
> Regards
> yacob
>
>
> ----- Original Message ----
> From: yacob sen <yacob_123_at_[hidden]>
> To: users_at_[hidden]
> 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.
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users