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Module overview

Environment variable manager​

Module is an HPC environment variable manager which can easily switch between different tools, solving the complex dependency problem when compiling or running applications.

With modules, you can switch environment variables to use specific packages, tools, or libraries without using the export command. Moreover, unlike the unset command, with just one module purge command you can remove all the environment variables.

info

The most common tool for HPC to manage environment variables is modules. Environment Modules is used traditionally, as Taiwania 1. Taiwania 2 (HPC CLI) adopts Lmod instead. The usage of the tools is similar, only the programming language is different.


Basic module commands​

  • List available modules module avail
  • List loaded modules module list
  • View modules instruction module whatis package1 package2 ...
  • Load specific modules module load package1 package2 ...
  • Unload specific modules module unload package1 package2 ...
  • Unload all modules module purge
tip

You can use ml to replace the above module command. Here are some examples:

  • List available modules ml av
  • Load specific modules ml package1 package2 ...
  • Remove specific modules ml -package1 -package2 ...

Basic module concepts​

  • Modules are organized in a hierarchical structure. Therefore, you must load a top level layer module before you can see the dependent modules at the next layer. In this way the wrong matching of packages can be avoided.
  • For examples, you must ml cuda/11.3 before you can see openmpi4/4.1.1, which is compilation dependent with cuda/11.3; you must load openmpi4/4.1.1, before you can see openmpi4/4.1.1, which is compile-dependent with fftw3/3.3.9.
  • The above example can be used as follows:
# Unload all module
ml purge
# Load specific modules
ml cuda/11.3 openmpi4/4.1.1 fftw3/3.3.9