Caffeine

CoArray Fortran Framework of Efficient Interfaces to Network Environments

Caffeine is a parallel runtime library that aims to support Fortran compilers with a programming-model-agnostic application binary interface (ABI) to various communication libraries. Current work is on supporting the ABI with the GASNet-EX exascale-ready networking middleware. Future plans include support for an alternative Message Passing Interface (MPI) back end.

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Prerequisites

Caffeine leverages the following non-parallel features of Fortran to simplify the writing of a portable, compact runtime-library that supports Fortran's parallel features:

Feature	Introduced in
The `iso_c_binding` module	Fortran 2003
The `contiguous` attribute [1]	Fortran 2008
`do concurrent` [2]	Fortran 2008
The `ISO_Fortran_binding.h` C header file	Fortran 2018
Assumed-type dummy arguments: `type(*)`,	Fortran 2018
Assumed-rank dummy arguments: `array(..)`,	Fortran 2018

[1] This requirement simplifies development but might be removed in a future release.

[2] This feature is used to support only co_reduce and might become optional in a future release.

Download, build, and run an example

git clone https://github.com/BerkeleyLab/caffeine.git
cd caffeine
./install.sh
export GASNET_PSHM_NODES=8
./build/run-fpm.sh run --example hello

Run tests

./build/run-fpm.sh test

Documentation

One of our continous integration (CI) scripts generates up-to-date Caffeine documentation using ford. The CI script also deploys the generated documentation to the our GitHub Pages site. Alternatively, generate HTML documentation locally using ford as follows:

ford doc-generator.md

Open doc/html/index.html in a web browser.

Funding

The Computer Languages and Systems Software (CLaSS) Group at Berkeley Lab leads Caffeine development under funding from the Exascale Computing Project (ECP).

License

See LICENSE.txt for usage terms and conditions.