An application compiled for 64-bit *IS* different from a 32-bit. But if both your 64-bit server and and 32-bit PC have compatible processor types, you can compile on the PC and run the program on the server. (as i told you in my previous mail)
Jody On Wed, Aug 13, 2008 at 10:15 AM, Rayne <lancer6...@yahoo.com> wrote: > Hi, > > I'm starting to think that the main problem lies in the 32-bit server not > being able to execute the program compiled by the 64-bit PC, and vice versa. > I just noticed that the sizes of the executables created by the PC and server > are different - the one created by the 64-bit PC is 3204 bytes larger. Does > that imply that the programs are somewhat different? > > I compiled the program using the server and created 32.out, then I compiled > the program using the PC and created 64.out. > > When I used the PC to run 32.out locally, I get the error: > "error while loading shared libraries: libmpi.so.0: wrong ELF class: > ELFCLASS64" > But when I used the PC to run 64.out locally, it ran fine. > > I got the following error message when I ran 64.out on the server locally: > > "Could not execute the executable "./a.out": Exec format error > > This could mean that your PATH or executable name is wrong, or that you do > not have the necessary permissions. Please ensure that your executable is > able to be found and executed." > > However, when I used the server to run 32.out locally, it ran fine. > > Does this mean that the errors I got are not due to incorrect setup of the > "MPI network", but the incompatibility issues of programs compiled by 32-bit > and 64-bit machines? > > Thank you. > > Regards, > Rayne > > --- On Wed, 13/8/08, jody <jody....@gmail.com> wrote: > >> From: jody <jody....@gmail.com> >> Subject: Re: [OMPI users] Setting up Open MPI to run on multiple servers >> To: lancer6...@yahoo.com, "Open MPI Users" <us...@open-mpi.org> >> Date: Wednesday, 13 August, 2008, 2:56 PM >> Hi Rayne >> >> SSH is used to start processes on the other machines - >> that's why you >> must configure ssh to work without passwords. >> >> As to your 64/32 bit problem: a program compiled for 32 >> bits usually >> works on a 64 bit machine, >> but not vice versa. There are methods to start MPI such >> that different >> executables are started >> on different machines, but iguess the easiest way to get >> things going >> would be to use >> 32 bit versions of your program on all your machines. >> >> Jody >> >> On Wed, Aug 13, 2008 at 4:52 AM, Rayne >> <lancer6...@yahoo.com> wrote: >> > Thank you for all the replies. >> > >> > Here's what I have now. >> > >> > I modified my .bash_profile on my server to include >> > the path of my executables, and now mpiexec and mpicc both >> > point to the correct ones. I tried setting the >> > LD_LIBRARY_PATH too, but it didn't seem to work, as it >> > kept telling me it couldn't find the sharded library >> > libmpi.so.0, although 'which libmpi.so.0' gave me >> > the correct location. Then I modified the /etc/ld.so.conf >> > file to include the directory of the libraries, and now the >> > MPI programs work correctly on the server. >> > >> > Now, my problem is that I have trouble running the >> > program using my PC and remotely on my server. I have the IP >> > address of my server in the openmpi-default-hostfile in my >> > PC, and I have set up a password-less ssh between them >> > (though I have set it up such that it asks for a >> > passphrase). All my programs and executables are in the >> > shared folder. However, when I tried to run the program on >> > my PC using 'mpiexec -n 2 ./a.out', I get the >> > following error: >> > >> > "Failed to find or execute the following >> > executable: >> > >> > Host: (Name of my server) >> > Executable: ./a.out >> > >> > Cannot continue." >> > >> > If I try to compile then execute the program locally, >> > on both my PC and server, they run fine. It's only when >> > I try to get both PC and server to run the program >> > concurrently, (which is the purpose of using MPI) that I get >> > the error. I have checked and the a.out file is exactly the >> > same on the PC and server, in terms of the size and >> > date/time modified. >> > >> > One thing is that my PC is a 64-bit machine, and my >> > server is a 32-bit machine. Could this be a factor, that a >> > program compiled on a 64-bit machine cannot run on a 32-bit >> > machine? >> > >> > Also, I don't quite understand the mechanism of >> > how MPI allows one machine to communicate with another. For >> > example, after compiling a program, an executable is created >> > and stored on that machine and also on the remote nodes, >> > through the use of a shared system. So when I run the >> > program, how does the machine I'm at get the remode >> > nodes to run the program too? >> > >> > Thank you, and sorry for the long email. >> > >> > Regards, >> > Rayne > > > New Email names for you! > Get the Email name you've always wanted on the new @ymail and @rocketmail. > Hurry before someone else does! > http://mail.promotions.yahoo.com/newdomains/sg/ > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
