====== Robot Operating System (ROS) ======

===== At Labs =====

At [[https://cyber.felk.cvut.cz/study/computer-labs/|labs]] (e.g., E130, E132), Robot Operating System (ROS) is available through [[https://en.wikipedia.org/wiki/Singularity_(software)|Singularity]] containers.

For **Ubuntu 18.04 + ROS Melodic**, run:\\
''singularity shell %%--%%nv /opt/singularity/robolab/melodic''\\
(''%%--%%nv'' is needed for graphical output, e.g. RViz)\\
Then source common aro catkin workspace:\\
''source /opt/ros/aro/setup.bash''\\
or, your own workspace:\\
''source ~/workspace/aro/devel/setup.bash''

For **Ubuntu 16.04 + ROS Kinetic**, run:\\
''singularity shell %%--%%nv /opt/ros''\\
(''%%--%%nv'' is needed for graphical output, e.g. RViz)\\
Then a catkin workspace has to be sourced, e.g. the system one:\\
''source /opt/ros/kinetic/setup.bash''\\
or your own workspace:\\
''source ~/workspace/aro/devel/setup.bash''

All images from Docker Hub are available too, e.g.:\\
''singularity shell %%--%%nv docker:%%//%%ros:kinetic-robot-xenial''\\
''singularity shell %%--%%nv docker:%%//%%ros:melodic-robot-bionic''\\
Note however that the images are quite large and download to your home (with limited space) by default:
So one may need to switch the cache directory somewhere else, e.g.:\\
''mkdir -p /tmp/$USER/singularity''\\
''ln -s /tmp/$USER/singularity ~/.singularity''
===== On GPU Servers =====

There are [[https://cyber.felk.cvut.cz/cs/study/gpu-servers/|GPU servers]] available via remote access (''ssh'').
Log in via one of these commands (use your faculty username):\\
''ssh -X username@cantor.felk.cvut.cz''\\
''ssh -X username@taylor.felk.cvut.cz''\\
Singularity images may also be located under ''/local/singularity_images''.
You can follow, more or less, the [[courses:aro:tutorials:ros#at_labs|instructions for labs]] once you are there.

Also, please read [[https://cyber.felk.cvut.cz/cs/study/gpu-servers/|the instructions]] on GPU usage.
Most notably, use at most one GPU at once.
Select GPU to use via environmental variable ''CUDA_VISIBLE_DEVICES'', e.g.\\
''CUDA_VISIBLE_DEVICES=2 my_command''\\
Prevent using any if you don't need it:\\
''CUDA_VISIBLE_DEVICES= my_command''\\
You can export it to stay in effect for all the following commands:\\
''export CUDA_VISIBLE_DEVICES=2''\\
''my_command''

===== On Your Computer =====

==== Linux ====

Follow [[http://wiki.ros.org/ROS/Installation]].
We use ROS Kinetic in the course, nevertheless, ROS Melodic should mostly be compatible.

You can also use the [[http://ptak.felk.cvut.cz/tradr/share/ros-kinetic-desktop-full.simg|Singularity image]] provided for labs, or modify the [[http://ptak.felk.cvut.cz/tradr/share/ros-kinetic-desktop-full.txt|Singularity recipe]] to build your custom image.

To build the image (on your own computer), you can use one of these commands:
  - ''
    $ sudo singularity build ros-kinetic-desktop-full.simg ros-kinetic-desktop-full.txt
    ''\\ or in general: \\ ''
    $ sudo singularity build <image_name>.simg <recipe_name>.txt
    '' 
  - Alternatively, you can build "an unpacked image" via \\ ''
    $ sudo singularity build %%--%%sandbox ros/ ros-kinetic-desktop-full.txt
    ''\\ or in general: \\ ''
    $ sudo singularity build %%--%%sandbox <image_folder> <recipe_name>.txt
    '' 
Both of these alternatives will create an image from the recipe. You can also edit the recipe (since it is a simple text file).
You need to use ''sudo'' when building images or use "fakeroot" (see ''singularity help build'' for more details).
The unpacked image is useful when you would like to add (install) additional packages to the image.
You can to this by running ''sudo singularity shell %%--%%writable <image_folder>'' after building the unpacked image. Afterwards, you should be able to use "apt-get install" to install additional packages.

==== Windows ====

  * Ubuntu in [[https://www.virtualbox.org/|VirtualBox]]
  * Via [[https://en.wikipedia.org/wiki/Windows_Subsystem_for_Linux|Windows Subsystem for Linux (WSL)]], see [[http://wiki.ros.org/Installation/Windows]]
    * Expect the support to be only partial as WSL have some limitations.
    * Use ROS Melodic with Ubuntu 18.04 or ROS Kinetic with Ubuntu 16.04. ROS installation instructions for Linux shoud work once you are in the Ubuntu Bash shell.
    * For applications with graphical output (e.g., RViz), you will need:
      * Running X Server for Windows (e.g., [[https://sourceforge.net/projects/xming/|XMing]])
      * Target X display specified (usually '':0'') when running graphical applications:\\ ''DIPLAY=:0 rosrun rviz rviz''
      * You can add it to ''~/.bashrc'' for it to stay in effect:\\ ''echo 'export DISPLAY=:0' > ~/.bashrc''
  * Dual boot with Ubuntu