option('rng_backend',type:'combo',choices:['stl_mt19937','stl_mt19937_64','internal_mersenne'],description:'The backend used for the random number generator provided by loadleveller')
option('rng_backend',type:'combo',choices:['internal_mersenne','stl_mt19937','stl_mt19937_64'],description:'The backend used for the random number generator provided by loadleveller')