I am using a parallel code which works fine with small array size on each slave node on a Linux cluster, say 40x40x40. But once I increased the array size, e.g. 80x80x80 on eachnode onthe samecluster, the code would fail with segmentation (sigsegv) error. I doubt it was the limit of the stack size, so set ulimit to unlimited. But the problem was still there. GDB tells me that the problemalways happensin array operations, i,e, A= 0.2B+C where A B C are all arrays. If I change the array operations to do-loops, then the code works for large arrays. This seems really strange to me. Anyone can shed some light? My system is ifort 8.1, redhat 9.0 and mpich 1.2.5. Thanks.