In Louhi the program development environment is managed using the modules package. For example, user's shell environment variables for different compiler suites, software packages and libraries are set up using the module tool.

Currently loaded modules are listed with command

module list

The environment changes induced by a particular module are shown with command

module show PrgEnv-pgi

The example above shows the effects of the default version of PGI programming environment. All available modules are listed with command

module avail

Loading and unloading modules files is done with module commands load and unload. Changing from the PGI programming environment to GNU programming environment, for example, is accomplished with the command

module swap PrgEnv-pgi PrgEnv-gnu

This, among other things, sets the Cray wrapper scripts to launch GNU compilers and link appropriate libraries for them. More examples of using the modules are provided in the chapter Program development of this User's Guide.