WIP: Fluctuating MRT

This merge request copies @winterhalter's effort from the old lbmpy repository (https://i10git.cs.fau.de/software/pystencils/merge_requests/37). The main things that are still missing are tests and generalization to non-D3Q19.

I guess this still needs https://i10git.cs.fau.de/software/pystencils/merge_requests/26 to be brought forward from the old repository as it doesn't generate any RNG calls.

Fixes #2 (closed). Related to walberla/walberla#80 (closed).

lbmpy/methods/__init__.py

@@ -3,10 +3,11 @@ from lbmpy.methods.momentbased import RelaxationInfo, AbstractLbMethod, Abstract
 from .conservedquantitycomputation import DensityVelocityComputation
 from lbmpy.methods.creationfunctions import create_srt, create_trt, create_trt_with_magic_number, create_trt_kbc, \
     create_mrt_orthogonal, create_mrt_raw, create_mrt3, \
+    create_fluctuating_mrt,\
     create_with_continuous_maxwellian_eq_moments, create_with_discrete_maxwellian_eq_moments
 
 __all__ = ['RelaxationInfo', 'AbstractLbMethod',
            'AbstractConservedQuantityComputation', 'DensityVelocityComputation', 'MomentBasedLbMethod',
            'create_srt', 'create_trt', 'create_trt_with_magic_number', 'create_trt_kbc',
-           'create_mrt_orthogonal', 'create_mrt_raw', 'create_mrt3',
+           'create_mrt_orthogonal', 'create_mrt_raw', 'create_mrt3', 'create_fluctuating_mrt',
            'create_with_continuous_maxwellian_eq_moments', 'create_with_discrete_maxwellian_eq_moments']