Meaning of num_threads, subscenes, slices?

In gymutil.py, there are three hyperparameters named as: num_threads, subscenes, slices. I checked the documentation as well, but the explanation is very concise. Would someone be able to explain these three terms in more detail? And when should we change the default value or what are good values for these terms? Thanks!

Hi @taocc,

The subscenes and slices parameters are mainly for use with CPU PhysX rather than the default GPU implementation. They were used in some of our early internal performance comparison work. You can leave these at their defaults and performance should be good.

The num_threads parameter controls how many CPU threads are used by PhysX. This still matters for GPU simulation because there are parts of the simulation work that can still happen on the CPU in some cases. We typically use 4 threads as a default in the example RL yaml configs that Isaac Gym ships with.

Take care,
-Gav

Thanks.