Small parameters you say... I wonder if a recent change in Java has significantly worsened its behavior with respect to denormalized floats [google for it]. BTW, MASON has the same CERN library available in sim/util/distribution/ though I don't see that method; it may be newer. Sean > On Mar 6, 2021, at 3:00 AM, Siamak Sarmady <[log in to unmask]> wrote: > > Hello again, > > I was forced to use a profiler to see what's wrong and it appears that a method in an external random number generator library (CERN Mersenne Twister library) was the culprit. > > The Poisson random number function would fall into a long loop for small Lambda parameters. I had modified the lambda to a small number in my simulation data files (not in the code). > > Removed the function and used my own simple code and I now got a wooping 100x simulation speed.... > > Sorry for taking your time guys > > <image.png> > > On Fri, 5 Mar 2021 at 15:18, Robert Zupko <[log in to unmask]> wrote: > Mac: > > I’ve seen that before when a new Java patch has been installed. We’re there any updates to the system? > > Regards, > Robert Zupko > > > On Mar 5, 2021, at 09:46, Mac Sarmady <[log in to unmask]> wrote: > > > > Hello > > > > I am using Java 11 to run mason simulations. A few weeks ago my simulations were reasonably fast (crowd simulation with a few hundreds agents). > > > > Then I had a pause and when I ran the simulations a few weeks later they are extremely slow (perhaps between 4 to 10 times?) > > > > - Has anyone encountered such a thing on his/her JVM and simulations? > > > > - Is there a benchmark on any of the mason examples that I can test and see whether the problem is from the installation or something inside my own code (I don't remember changing it in the period)? > > > > Regards, > > Mac