- counter-based philox RNG: counter/key is filled with cell coordinate
  and optional external parameters like block position and time step
- works on CPU and GPU - on CPU only for non-vectorized versions

- introduced more flexible "CustomCodeNode" that can inject
  backend-specific hand-written code

- new functions to easily extract stencil coefficients and visualize them
- Moved stencil functions from lbmpy to pystencils

- test run again
- notebooks not yet

- Previously sympy.Eq was used to represent assignments. However Eq
  represents equality not assignment. This means that sometimes sympy
  "simplified" an equation like a = a  to True,
-> replaced sp.Eq by pystencils.Assignment everywhere
- renamed EquationCollection to AssignmentCollection

- in-kernel Neumann boundaries
- flag-interface for boundary handling makes one flag field multiple
  boundary handlings possible
- generator: support for bitwise logical operators

- splitted existing LBM boundary handling into two parts:
    -> generic part , that is used for FD as well and moved it to pystencils
    -> LBM specific part - remained in lbmpy

- bugfixes

- plotting
- calculation of force on boundary
- vtk outpu

- easy and efficient access to fluid, boundary and link positions
  through BoundaryDataSetter object
- more code reuse for serial and parallel setups

- boundary conditions can now define their own state
- boundary classes instead of functions
- no boundary name any more
  (instead the identity is defined via instances)
- updated tutorials accordingly
- boundary handling now gets pdf numpy array instead of pystencils field

- periodic kernels not yet OpenMP parallel

previously the value was taken from the cell next to the boundary cell (i.e. the inner cell)

- documentation for lbmpy creationfunctions
- new tutorial
- boundary handling: various helpers to setup geometry

- bugfix for CUDA kernels with variable field sizes
- extended tests for pystencils gpu kernels

Michael Kuron authored 8 years ago and Martin Bauer committed 8 years ago

This commit makes the Python code backwards compatible down to Python 2.7. Previously it would only run on Python 3.5 and up.

Problems fixed included:
- `time.perf_counter()` doesn't exist
- all classes need to be new-style
- `functools.lru_cache` doesn't exist
- only the last argument to a function call can be `*`-expanded
- the `nonlocal` keyword doesn't exist
- metaclasses are used with a different syntax
- `yield from` doesn't exist
- `tempdir.TemporaryDirectory` doesn't exist
- iterators need a `next()` method