Hello all,

I am having problems with the compilation of a fortran program (a mix of f77 and f90) on 64 Bits machines. I am using this program in parallel with MPICH2 for 64 Bits machines. In fact when I compile my program on 32 bits machine and use it on 32 Bits machines in parallel I have no problem, but when i use it on 64 Bits machines the program buggs and sends out NaN. I have asked someone to test my program on 64 Bits machines and he has no problem running it.
So now I am compiling it on a 64 Bits machine, and the program runs but 3 to 4 times slower than usual, and even slower than on 32 Bits machines. And after a couple of hours it stops without any error messages.
I don't really know what to try now, I have tried to use it in a non parallel way, but it is still as slow...
Does someone has any idea ? I would really appreciate it!

Thank you


PS: I am on linux debian (etch), and the 64 Bits machines are AMD64.

Perhaps the libraries you are using aren't 64-bit? When you run a 64-bit binary, the libraries it depends on must also be 64-bit, not 32-bit. Sure, the 64-bit processor can execute 32-bit code natively, but it requires 32-bit libraries to go with it.