UMAT using multiple cpus

[creanea]

Hi all,

I've written a UMAT in abaqus and it works fine on a 32bit XP machine with multiple cpus. But I've moved to a 64bit vista machine and while the simulations converge when I use one cpu they don't when I try to use anymore. This makes absolutely no sense to me, could anyone explain? Abaqus verification UMATs still work fine with multiple cpus.

Any help is much appreciated,
Thanks

[Jorgen]

You should make sure your UMAT is "thread safe". I.e. it should not use any global variables, or other constructions that do not work on multiple CPUs. It sounds like your UMAT already is safe since it works on a 32-bit XP machine.

I am not sure what is going on. Do you use a different compiler on the 64-bit computer?

-Jorgen

[creanea]

Thanks Jorgen,

I had been using intel visual fortran 9.1 compiler (64 bit for the 64 bit computer and 32 bit for the 32 bit computer). After a couple of days I still couldn't figure out what was wrong so I gave up. I installed Abaqus 32 bit on the 64 bit computer and compiled with the 32 bit version. Everything works fine now using all cpus although I may be increasing the required computation time. I would still like to know why it wasn't working but have no ideas?