I'm trying to run a code on ssh that works perfect for a smaller mesh , but since the new mesh is much bigger i used ifort command to compile it, ifort -mcmodel=medium -i-dynamic -otest.out*.f
and it complies but when i run it , the output is: killed
i know that problem is from memory, does anyone know if there's any way to run it? how can i understand where in code cause memory problem?
Thanks shadi
try using valgrind. i tried it to find memory leaks in my fortran code with good success.
From the ifort command line, I think you are running on Linux.
Seeing "killed" as output is generally the result of Linux's Out Of Memory killer (OOM) getting involved to prevent an impending crash (because it's common practice for applications to ask for more memory then they need requests for more memory than is currently available are accepted - check for "Out of Memory: Killed process [PID] [process name]" in the system log files). The OOM killer is generally pretty good at disposing of the application responsible for using all the memory, so the place to start is your applications memory usage.
The first thing to do is try and estimate (even if it's only roughly) how much memory you expect your application to use. One approach is to guestimate the size of the major arrays and multiply them by the number of bits needed per element. Another approach is to think about how you would expect the memory use to grow with mesh size. You can study this by experiment (run with different mesh sizes, measure the memory use and extrapolate) or from one measurement and knowledge of how the major array scale. It may be that you are asking for much more memory then you have on the machine: and the solution to this is probably to get a access to bigger computer. (Or you could try and find an alternative algorithm which uses less memory.)
If their is a memory leak you should see more memory use than expected, even for the smaller mesh size. If this is the case, valgrind should help. Moving from static to dynamic storage probably isn't going to help here - I would expect to see a segmentation fault if you were just exceeding the available space on the stack.