Futhark is a purely functional data-parallel programming language in the ML family. It can be compiled to typically very efficient parallel code, running on either a CPU or GPU. The language is developed at DIKU at the University of Copenhagen, originally as part of the HIPERFIT centre. It is quite stable and suitable for practical programming.
For more information, see:
Parallel Programming in Futhark, an extensive introduction and guide
Issues tagged with good first issue do not require deep knowledge of the code base.
For contributing code, see the hacking instructions.