NOTE This has only been tested on Ubuntu 20.04 and compiled with g++-11.
Be aware that the steps below do not actually install LAL in your computer; you will be able to use LAL but Windows will not be aware that you "installed" it, that is, you will not be able to remove LAL via the useful
$ sudo apt remove ...
Head over to LAL's official webpage and download the appropriate C++17 core depending on the release you want to use. The file should be named ubuntu20-c++-libs.zip. Uncompress the files in any directory, say the Desktop. Open a command line terminal and navigate to the directory you chose. If you used the Desktop, run the command
$ cd ~/Desktop
With sudo permissions, the easiest procedure to installing the library may be to move the include and lib folders into the /usr directory. For this, execute the commands
$ sudo cp -r include/* /usr/include/
$ sudo cp lib/* /usr/lib
If you do not have sudo permissions, an alternative way of installing LAL is to place the include and lib folders inside a directory of your choice, say, /path/to/LAL and then updating the necessary environment variables. To do so, get the full path of these directories. The path can be easily found by opening a terminal in said directories (navigate into them with a file browser, right-click on them and select Open Terminal here or similar) and running
$ echo $PWD
Finally, update the environment variables by running the following commands:
$ export CPLUS_INCLUDE_PATH=/path/to/LAL/include:$CPLUS_INCLUDE_PATH
$ export LD_LIBRARY_PATH=/path/to/LAL/lib:$LD_LIBRARY_PATH
We recommend to add these three commands in your .bashrc file, or equivalent, so that they are run automatically every time a new terminal is opened.
To link an executable file against the debug build of LAL, issue the following command
$ g++ -D_GLIBCXX_DEBUG -std=c++17 *.o -I /path/to/lal/headers -L /path/to/lal -llal -lgmp -fopenmp -lpthread
To link an executable file against the release build of LAL, issue the following command
$ g++ -std=c++17 *.o -I /path/to/lal/headers -L /path/to/lal -llaloptimized -lgmp -fopenmp -lpthread