- test_serial_scenarios already tested if waLBerla is available by catching ImportErrors
- importorskip from pytest throws another exception, which is not part of the public API
-> catching all exceptions - which is not really elegant but works

- also for default MRT methods its better to use symbolic RR's instead of inserting numeric values for them
- but then the simplification strategy developed for SRT/TRT has to be disabled
- this commit introduces two new options:
     - simplification='auto' or a custom SimplificationStrategy
     - 'keep_rrs_symbolic'=True, by default now RRs are left symbolic

Execute LBM scenario with OpenCL

See merge request !13

Add custom timeloop_creation_function for LatticeBoltzmannStep

See merge request !20

Skip some tests if waLBerla is not installed

See merge request pycodegen/lbmpy!18

update of the kernel equations for the phase field model

See merge request !19

minor documentation fix for Shan-Chen

See merge request !21

are much faster in certain setups

With this update all derivatives are derived automatically with the functionality of pystencils.
Furthermore more testcases are provided.

- more time steps to get to stable solution

Use Gram-Schmidt for create_mrt_orthogonal

Closes #5

See merge request !17

- "mrt" now takes relaxation rates [shear, bulk, 3rd order, 4th order..]
- deprecated "mrt3": use orthogonalized mrt now
- fixed wrong test

shear previously ignored the diagonal moments and bulk didn't exist

- orthogonalize automatically if no moments from literature are provided
- must specify whether weighted or unweighted orthogonality is desired

Fluctuating MRT: requires weighted-orthogonal method

Closes #6

See merge request pycodegen/lbmpy!15

Test for fluctuating LB, avg temperature and velocity distribution

Closes #4

See merge request pycodegen/lbmpy!16

It compiles so it's correct I guess...