A lot of ECJ version-to-version is bugfixes and cleanups and simplificaiton, and certainly ECJ 21 is a lot of that.  But it also includes (off the top of my head) GE, Push, an entirely new PSO facility, Meta-GAs, improved distributed evaluation, significantly stronger coevolutionary facilities, GP benchmarks, and a bunch of new problems.

Sean

On May 3, 2013, at 4:27 PM, Warren Henning wrote:

> What are the biggest changes/new features in ECJ 21?
>
> Warren
>
>
> On Fri, May 3, 2013 at 12:57 PM, Sean Luke <[log in to unmask]> wrote:
> GMU's ECLab, Autonomous Robotics Laboratory, and Center for Social Complexity are proud to announce the official released of ECJ version 21 and MASON version 17.  They are available here:
>
>         http://cs.gmu.edu/~eclab/projects/ecj/
>         http://cs.gmu.edu/~eclab/projects/mason/
>
> These released have been a long time in coming: between 1 and 2 years.  They reflect a significant degree of improvement of both the systems, and the assistance of a significant number of people to whom we are thankful.
>
> ECJ is a high-performance evolutionary computation and stochastic optimization system written in Java.  MASON is a high performance ultralight multiagent simulation toolkit intended for "swarm"-style simulations.
>
> Sean Luke
>