Hi Otheus, same error as the other day, just that i accidently didnt copy the part of the error about there needing to be a certain number of processes for the test. The thing is, when i change the P and Q values to 1 and 1 respectively within the HPL.dat file, it works, and it performs the tests. The moment i make them anything other than 1 and 1, such as 2 and 4 to run across 8 processes on 2 nodes, then it gives me the original error message.

Been stumped for weeks now =(

Edit: The full error message being received is still the same as the other one:

"HPL ERROR from process # 0, on line 419 of function HPL_pdinfo:
>>> Need at least 8 processes for these tests <<<

HPL ERROR from process # 0, on line 621 of function HPL_pdinfo:
>>> Illegal input in file HPL.dat. Exiting ... <"

Did you make sure you compiled with your MPI installation, with mpicc ??

Hi Otheus, thanks for your reply.

By "compiled with your MPI installation", do you mean simply placing openmpi in the execution line, such as:

mpirun -np 8 -machinefile machines xhpl_em64t

That is the line i have been using, to make use of openmpi.

I apologise if this is not what you meant, i am still very new to all this, as well as linux, a total newbie i might add, but decided to take on this challenging task at uni for a research topic, and to learn about linux.

Hoping you can shed some light on what you meant by "compiled with your MPI installation", or how i go about doing this.

Thanks Otheus.

How did you compile and install this program?

Oh the software was already installed by the university. I am using the university cluster to run these tests, with open mpi, and Linpack Benchmark all already installed and have been told by the administrator that they are all working properly, and that i just need to know how to learn to use Linpack and tune the Dat file.

Just that once the values of P and Q are other than 1 and 1 in the dat file, then the errors begin.

Uh-hunh. I wouldn't completely trust that if I were you. Let's take it step-by-step.

1. Use "type" or "which" or "whence" to find the full path of the linpack executable:
   
   Code:

   type -a hpl

2. verify this has been compiled dynamically and not statically:
   
   Code:

   file <hpl path from step 1>

   You should see something like "Dynamically linked i386 object". As long as you don't see "statically linked binary" proceed to the next step. Otherwise, talk to your system admin and ask him/her very specifically how he/she compiled it.
3. Next, run
   
   Code:

   ldd <hpl path from step 1>

   You should see something like "libopen-rte.so" in the output. If you do not, ask your sysadmin to point you to the correct hpl, the one this is compiled "against" (with) the openMPI runtimes.
4. The libopen-rte.so should point to the full path of a file. If it does not, again, go to your system administrator and ask him/her for the full LD_LIBRARY_PATH that you should have to run against this hpl program.
5. The path should be available to you by default on all machines in the cluster. If not, add the LD_LIBRARY_PATH setting into the .bashrc file and include your .bashrc from your .bash_profile (if you're using csh, god help you; if ksh, just change the names to .kshrc and .profile). Now log into the other machine and run the ldd command as above; you should see the line pointing to the full path of the MPI rte library.
6. Make sure this all works by running:
   
   Code:

   mpirun -np 8 printenv LD_LIBRARY_PATH

   You should get 8 instances of the correct LD_LIBRARY_PATH.
7. Now go back and try getting this to run for exactly 2 processes. (P=2, Q=1, -np 2)
8. Now modify the machine file so it has two lines in it, one for each hostname, and run it again.
9. If we're at this point, try again with 8; if it fails, there are some other things to look at and try.

Hi Otheus. After typing in which -a hpl, this is what comes up:

/usr/bin/which: no hpl in (/usr/local/openmpi-1.2.6/bin:/usr/local/lam-7.1.4/bin:/usr/local/openmpi-1.2.6/bin:/usr/local/lam-7.1.4/bin:/usr/lib64/qt-3.3/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/NX/bin:/home/jleungsh/bin:/usr/NX/bin)

Which of those directories is the correct one?

I have skipped down to step 6 in the mean time, and i get this:

[jleungsh@hydrus14 em64t]$ mpirun -np 8 printenv LD_LIBRARY_PATH
/usr/local/openmpi-1.2.6/lib:
/usr/local/openmpi-1.2.6/lib:
/usr/local/openmpi-1.2.6/lib:
/usr/local/openmpi-1.2.6/lib:
/usr/local/openmpi-1.2.6/lib:
/usr/local/openmpi-1.2.6/lib:
/usr/local/openmpi-1.2.6/lib:
/usr/local/openmpi-1.2.6/lib:



Thanks