MultithreadCorner/Hydra: Hydra 3.2.1

Hydra is a C++14 compliant and header only framework designed to perform common data analysis tasks on massively parallel platforms. Hydra provides a collection of containers and algorithms commonly used in HEP data analysis, which can deploy transparently OpenMP, CUDA and TBB enabled devices, allowing the user to re-use the same code across a large range of available multi-core CPU and accelerators. The framework design is focused on performance and precision. The core algorithms follow as close as possible the implementations widely used in frameworks like ROOT and libraries like GSL. Hydra 3.2.1 ======= This release: 1) In certain corner cases, a substantial part of the calculations performed to evaluate a functor depends only on the functor's state and it's parameters; i.e. it does not depend on the current functor's arguments that can be dataset points, numerical integration abscissas and so on. To further optimize the calculations in these cases, Hydra now provides the method virtual void hydra::Parameter::Update(void), which can be overridden by the functors in order to pre-calculate the factors only depending in the parameters, before the calculations are distributed to one of the parallel backends. 2) Introduction of hydra::random_range and retirement of hydra::random_uniform_range, hydra::random_gaussian_range, hydra::random_exp_range , to define iterators for drawing samples from functors. Examples updated accordingly. Bug fixes: 1) ROOT examples updated and tested against ROOT/6.22.00. ( https://github.com/MultithreadCorner/Hydra/commit/acd303e7fb21d220beb7986ab7122206ac6a8eed ) 2) Correction of hydra::CrystalBallShape math. ( https://github.com/MultithreadCorner/Hydra/commit/a7ce56d4c9efad46351ddee630f7afce245c9909 ) 3) Spelling of some words (in code) accross the tree. (https://github.com/MultithreadCorner/Hydra/commit/d2161898bd9ed4e09ee6593d27372c8ad43347b1) 4) Fixing fallback path in MSB.h. ( https://github.com/MultithreadCorner/Hydra/commit/5b10e05e2517c27f270507c27ea76c85a62e24f5 ) 5) Reimplementation of hydra::detail::is_valid_type_pack ( https://github.com/MultithreadCorner/Hydra/commit/f30b97a414f513e3e410195555bd0eb8f44eb9f9 ) 6) Many other minor bug fixes across the tree..