Arrgh. It was a simple data structure issue. There was a piece of code that called toArray() on a HashSet. Of course, there's no guarantee that the order of the items in the returned array is the same from run to run. Thanks for the sanity check, Angel Martinez RAND Corporation -----Original Message----- From: MASON Multiagent Simulation Toolkit [mailto:[log in to unmask]] On Behalf Of Sean Luke Sent: Tuesday, June 14, 2011 11:41 AM To: [log in to unmask] Subject: Re: Setting the random seed My #1 guess: are you calling Math.random() ever? My #2 guess: are you using multiple threads, but not locking on the schedule prior to accessing the generator? Lemme know how it turns out. Sean On Jun 14, 2011, at 11:33 AM, Martinez, Angel wrote: > Sean, > > Thanks. I've rechecked and nextInt() is providing the same start > sequence as expected. Somehow, my code is still producing non- > repeatable > behavior despite the fixed sequence. The ball is in my court now. > > Best, > > Angel Martine > RAND Corporation __________________________________________________________________________ This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message.