CLFORTRAN

"CLFORTRAN is an open source (LGPL) Fortran module, designed to provide direct access to GPU, CPU and accelerator based computing resources available by the OpenCL standard.

 Taking advantage of recent Fortran language features, CLFORTRAN is implemented in pure Fortran (no C/C++ code involved). Therefore, it allows scientists to add GPU capabilities nativeley to a familiar Fortran environment.

Providing complete access to OpenCL API, the module is standard conformant, written in simple Fortran and maintains the same functional signature as in C/C++, to allow knowledge reuse and greater flexibility."

http://www.cass-hpc.com/solutions/libraries/clfortran-pure-fortran-interface-to-opencl/

https://github.com/cass-support/clfortran