-- currently doesn't work -- implementation of (hopefully) GPU hierarchical gaussian mixture models in futhark originally developed and tested using an old nightly version of futhark and then updated to mostly compile with the latest (as of 7/27/2019) doesn't currently work, unit_test_pdf is the closest to actually working but segfaults with the 'python' backend and the pyopencl backend doesn't work uses the livingRoom0 dataset from ICL-NIUM: https://www.doc.ic.ac.uk/~ahanda/VaFRIC/iclnuim.html