Frequently asked questions

This is a list of frequently asked questions. Feel free to suggest new entries!

What do I need for rendering images in SMARTS?
Need x11 or a dummy of that rendering system on Linux. We recommend a decent GPU if you are training an Agent that makes use of observation’s depending on the rendering pipeline such as TopDownRGB, OGM, or DriveableGridMap.
Where can I find debug logs?
In most cases SMARTS debug logs are located at ~/.smarts. These can be helpful to diagnose problems.

Exception: Could not open display. (Ubuntu)

This may be due to needing a display to render with a GL renderer backend setting. Try the following instructions to solve it.

# Set DISPLAY, can be as needed
$ echo export DISPLAY=":1" >> ~/.bashrc
$ source ~/.bashrc

# Do once: Install x11 dummy which allows creating a fake display
$ sudo apt-get install -y xserver-xorg-video-dummy x11-apps
# Potentially the following if you need software rendering:
# sudo apt-get install -y mesa-utils

# Do once: set xorg server
$ sudo wget -O /etc/X11/xorg.conf http://xpra.org/xorg.conf

# Do as needed:
$ sudo /usr/bin/Xorg -noreset +extension GLX +extension RANDR +extension RENDER -logfile ./xdummy.log -config /etc/X11/xorg.conf $DISPLAY &

Note that mesa-utils installs llvm, which is one option out of several that emulate OpenGL using software. llvm is not needed if a GPU is available.

Custom rendering and Obfuscation maps show completely blank. (Ubuntu)
This is due to needing OpenGL to render using scripts. If you have a GPU make sure OpenGL is installed and the GPU has the necessary drivers for rendering.

See the previous question if you need software rendering.
The simulation keeps crashing on connection in SumoTrafficSimulation. How do I fix this?
This is likely due to using large scale parallelization. You will want to use the centralized management server. See With the default behaviour each SMARTS instance will attempt to ask the operating system.