On a Linux machine with GAP installed, the HAP library can be loaded as follows:

- First download the file hap1.4.tar.gz (or the more recent hap.current.tar.gz) to the subdirectory "pkg/" of GAP. (If you don't have access to this, then create a directory "pkg" in your home directory and download the file there.)

- Change to directory "pkg/" and type "gunzip hap1.4.tar.gz" followed by "tar -xvf hap1.4.tar" .

- Start GAP. (If you have created "pkg" in your home directory then start GAP with the command "gap -l 'path/homedir;' " where path/homedir is the path to your home directory.)

- In GAP type " LoadPackage("HAP"); "

- Help on HAP can be found on the HAP home page (a version of which is included in directory "pkg/Hap1.4/www" of the distribution).

- A few of HAP's (optional) functions rely on Polymake software (available from
  www.math.tu-berlin.de/polymake/) which should be installed so that it starts
  using the command "polymake" at the Linux prompt.

- Performance can be significantly improved by using a compiled version of the HAP library. The following steps will produce a compiled version. (1) In the file "pkg/Hap1.4/read.g" set "COMPILED:=true;" . (2) In the file "pkg/Hap1.4/lib/compiledVersion.gap" adjust the path names appropriately. (3) It might be necessary to us the GAC compiler to recompile the various "file.so" files in the directories "pkg/Hap1.4/lib/***/Compiled . This can be done by typing something like "gap4r4/bin/i686-pc-linux-gnu-gcc/gac -d file.gi" .