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RoboCup-SSL / grSim

RoboCup Small Size Robot Soccer Simulator
https://ssl.robocup.org/league-software/
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Speedup Simulation time #113

Closed goncamateus closed 4 years ago

goncamateus commented 4 years ago

Hi guys! I'm trying to use grSim to train some Reinforcement Learning algorithms. The whole environment is already set but I'm stucked with the simulation time problem. grSim runs in real time and I want it to be something like 30+ times faster. Is there a way to do this? Have someone already tried?

Thank you in advance!

mahi97 commented 4 years ago

Hi There are some configs under Physics/World that you can find in the configuration in gui.

Desired FPS shows how many loops you want the simulator takes in one second. ODE time step shows how many seconds the simulator goes forward in each loop. So for realtime simulation, the product of these numbers should be 1.

You can tune these numbers to get the product to 30, but there are drawbacks. If you increase the Desired FPS, it consumes more resources, and you may not have enough. If you increase the ODE time step, it reduces the accuracy of the simulator.

I suggest to also use the headless mode by running grsim with additional --headless or -h argument to help the speed.

mahi97 commented 4 years ago

Also if you need more speed and don't care about the noise you can replace this line: https://github.com/RoboCup-SSL/grSim/blob/a2a407d9785106d27876304099556ab862234d01/src/physics/pworld.cpp#L171 With dWorldQuickStep function.

I guarantee that this is not working well, but it runs way too faster. Improve performance by 50%. Usually, headless mode improves performance by 15%. So I suggest to combine them if you need more speed.

Another point that I missed, If you increase the ODE time step too much, your robots can pass through walls or other robots at high speeds. so be careful with it :wink:

goncamateus commented 4 years ago

Nice! Thank you very much! I'm gonna try that!