# Linux (and Solaris)¶

These instructions apply to most Linux distributions. They apply to Solaris with little or no change.

The two options, in order of preference, are:

## Compiling the Sofware from Source¶

For users who are not familiar with git, see Help with git. git is a software management tool, and is included by default on most linux distributions.

Choose a directory on your machine to store the source code. Use your terminal to navigate into that directory, then type:

git clone https://github.com/jeffreyadams/atlasofliegroups.git


This creates a subdirectory atlasofliegroups and stores the files there.

### Compile¶

After you have the source code, cd to the atlasofliegroups directory.

Type:

make


If all goes well you will have an executable file atlas. Give the command:

atlas


You should see something like:

This is 'atlas' (version 1.1, axis language version 1.0),
the Atlas of Lie Groups and Representations interpreter,
compiled on Dec 30 2021 at 16:01:25.   http://www.liegroups.org/


Congratulations! Go on to After compiling for the next steps.

You may need to edit the Makefile to change the line CXX = g++ -std=c++0x to something different, depending on your system (this is specifying the C++ compiler).

To find out your default compiler give the command:

g++ --version


The software has been well tested with g++ versions 4.8 and above.

The most likely reason for an error has to do with the readline library. The software will run without it. To see if this is the problem give command:

make readline=false


If this succeeds, you have a functioning version of the software, but without the readline functions.

### After compiling¶

We recommend running:

make install


(from the atlasofliegroups directory) to make atlas accessible from anywhere. By default this will put a shell script in ~/bin and points to the atlas-scripts directory. Make sure thath ~/bin is in your path. Then the command atlas will run the software.

The software relies on a large set of auxiliary files in the directory atlasofliegroups/atlas-scripts, with the suffix .at (or .ax). Generally you want to load all of these, by loading the single file all.at. This happens automatically if you use make install.

See the Makefile for other options.

### Other ways of launching atlas¶

Alternatively you can launch atlas and tell it where to find the scripts. Here are few examples.

We recommend creating a directory atlasofliegroups/my_files, and always starting atlas from there. Assuming you’ve run make install, you can do:

cd atlasofliegroups
mkdir my_files
cd my_files
atlas


This will read the necessary files from the directory atlasofliegroups/atlas-scripts, and any files you write to will be in atlasofliegroups/my_files. Another possibility (which doesn’t require make install is:

cd atlasofliegroups
mkdir my_files
cd my_files
../atlas --path=../atlas-scripts all.at


Alternatively go to thedirectory in which you built the software and run atlas from there:

cd atlasofliegroups
./atlas --path=atlas-scripts all.at


The path argument tells atlas where to find the scripts, and all.at says to load most of the scripts (possibly excluding a few which are under development).

Another option is to run atlas from the atlas-scripts directory, in which case it doesn’t need the path:

cd atlasofliegroups/atlas-scripts
../atlas all.at


The compiler also produces an executable file Fokko’’ which has the core software but not the scripting language.

### File Input and Output¶

When you read files from within atlas it looks in the working directory (from which you launched atlas) and the atlas-scripts directory, or whatever directory (or directories) you speficy with --path.

When the atlas software writes output to a file, it is always in the working directory.

Assuming you ran make install as above you don’t need to do anything else. Files will be read from the working directory (from which you launched atlas) and the atlas-scripts directory. Output will go to files in the working directory.

#### Other Compile Options¶

When you compile the software by running make, there are some other options available. Among these:

make optimize=true


is recommended: the compilation is slower, but the code runs substantially faster.

See the Makefile for more options.

##### Updating the atlas software¶

At any time you can update the atlas software using git. In the atlasofliegroups directory give the command:

git pull origin master


Assuming you have not edited any of the files in the distribution this will update the source code to the latest version. Typically you will not need to run bmake again. This is the case if the only files that changes (git reports this) are *.at files. If any files such as *.cpp files where changed, you should run make again.

If you get any errors due to conflicts you can try to resolve them. This can sometimes be tricky. A fallback option is to reinstall the software from scratch again.

## Using Docker¶

The preferred method is to compile the software from source. The next choice is using the Docker container system.

This installs a container, which is a self-contained linux environment (similar to a virtual machine) on your machine which is called the host. The atlas software runs entirely in the container, so is less dependent on the details of your system. This is a good option of you have trouble compiling the software yourself.

This requires adminsitrative privileges, so is mainly used for personal machines, and not institutional machines under the control of a system administrator. Also since the software is running in a container a little more effort is required for file input and output.

Install docker (community version) for your system from https://www.docker.com/community-edition

Note

The default way to install docker is as root, i.e. using sudo. Assuming you do this every docker command must be preceded by sudo as illustrated here. It is possible to install and run docker in rootless mode.

Give the command:

sudo docker run -it jeffreyadams/atlasofliegroups:version1.1


to download the software and run it (it launches atlas and reads in the file all.at). docker needs to be run as root, so all docker commands are preceded by sudo. The first time you do this it takes up to a few minutes. Subsequent times it is much faster.

To get the latest update, give the command:

sudo docker pull jeffreyadams/atlasofliegroups:version1.1


## File Input and Output in Docker¶

Since docker runs in a container, some extra effort is required to make files read/write from the host system. Here is an example, assuming your username is joe_user, your home directory is /home/joe_user, and you want to work in a subdirectory my_files of your home directory:

sudo docker run -it --mount type=bind,source=/home/joe_user/my_files,\


(Note: the \ indicates a new line, and no space is allowed after the comma. On some systems this should be entered as a single line.)

Now atlas will run as usual. Any files you write using atlas will be visible from the host system in the my_files directory. You can add files to this directory from the host filesystem, and atlas can read them.

Since docker is running as root, any files that atlas creates (which you can see in youor my_files directory) are owned by root. They are readable, but you must be root to write to them. You can copy any file to another file, in which case the new file will be readable/writable by you, and visible to atlas.

### Other Docker Commands¶

Here are a few other frequently used docker commands:

sudo docker images
sudo docker image ls


to list the images docker knows about. Similarly:

sudo docker container ls


to list the running containers (each container has a container id). Occasionally you will need the container id, as in:

sudo docker container kill container_id


to kill a container that is running. This command:

sudo docker container prune
`

gets rid of containers that are no longer running.