lbmpy codegen script, stub application source, and CMakeLists.

apps/tutorials/codegen/02_LBMLatticeModelGeneration.cpp

+//======================================================================================================================
+//
+//  This file is part of waLBerla. waLBerla is free software: you can
+//  redistribute it and/or modify it under the terms of the GNU General Public
+//  License as published by the Free Software Foundation, either version 3 of
+//  the License, or (at your option) any later version.
+//
+//  waLBerla is distributed in the hope that it will be useful, but WITHOUT
+//  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+//  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+//  for more details.
+//
+//  You should have received a copy of the GNU General Public License along
+//  with waLBerla (see COPYING.txt). If not, see <http://www.gnu.org/licenses/>.
+//
+//! \file 02_LBMLatticeModelGeneration.cpp
+//! \author Frederik Hennig <frederik.hennig@fau.de>
+//
+//======================================================================================================================
+
+#include "blockforest/all.h"
+#include "core/all.h"
+#include "domain_decomposition/all.h"
+#include "field/all.h"
+#include "geometry/all.h"
+#include "timeloop/all.h"
+
+#include "lbm/field/PdfField.h"
+#include "lbm/field/AddToStorage.h"
+#include "lbm/communication/PdfFieldPackInfo.h"
+#include "lbm/vtk/VTKOutput.h"
+
+//    Codegen Includes
+#include "SRTLatticeModel.h"
+#include "CumulantMRTLatticeModel.h"
+#include "EntropicMRTLatticeModel.h"
+
+namespace walberla{
+
+// Set a typedef alias for our generated lattice model, for convenience.
+typedef lbm::SRTLatticeModel LatticeModel_T;
+
+// Also set aliases for the stencils involved...
+typedef LatticeModel_T::Stencil                   Stencil_T;
+typedef LatticeModel_T::CommunicationStencil      CommunicationStencil_T;
+
+// ... and for the required field types. These include the PdfField for the simulation
+typedef lbm::PdfField< LatticeModel_T >           PdfField_T;
+
+// and scalar- and vector-valued fields for output of macroscopic quantities.
+typedef GhostLayerField< real_t, LatticeModel_T::Stencil::D > VectorField_T;
+typedef GhostLayerField< real_t, 1 > ScalarField_T;
+
+// Also, for boundary handling, a flag data type and flag field are required.
+typedef walberla::uint8_t    flag_t;
+typedef FlagField< flag_t >  FlagField_T;
+
+int main( int argc, char ** argv )
+{
+   walberla::Environment walberlaEnv( argc, argv );
+
+   auto blocks = blockforest::createUniformBlockGridFromConfig( walberlaEnv.config() );
+
+   // read parameters
+   auto parameters = walberlaEnv.config()->getOneBlock( "Parameters" );
+
+   const real_t          omega           = parameters.getParameter< real_t >         ( "omega",           real_c( 1.4 ) );
+   const Vector3<real_t> initialVelocity = parameters.getParameter< Vector3<real_t> >( "initialVelocity", Vector3<real_t>() );
+   const uint_t          timesteps       = parameters.getParameter< uint_t >         ( "timesteps",       uint_c( 10 )  );
+
+   const double remainingTimeLoggerFrequency = parameters.getParameter< double >( "remainingTimeLoggerFrequency", 3.0 ); // in seconds
+
+   // create fields
+
+   // TODO: Do we need a force field?
+   //BlockDataID forceFieldId = field::addToStorage<VectorField_T>( blocks, "Force", real_t( 0.0 ));
+   
+   // Velocity output field
+   BlockDataID velFieldId = field::addToStorage<VectorField_T>( blocks, "Velocity", real_t( 0.0 ));
+
+   LatticeModel_T latticeModel = LatticeModel_T(velFieldId, omega );
+   BlockDataID pdfFieldId = lbm::addPdfFieldToStorage( blocks, "pdf field", latticeModel, initialVelocity, real_t(1) );
+   BlockDataID flagFieldId = field::addFlagFieldToStorage< FlagField_T >( blocks, "flag field" );
+
+   // create and initialize boundary handling
+   const FlagUID fluidFlagUID( "Fluid" );
+
+
+   auto boundariesConfig = walberlaEnv.config()->getOneBlock( "Boundaries" );
+
+   // TODO: Replace by my NoSlip
+   // lbm::LbCodeGenerationExample_NoSlip noSlip(blocks, pdfFieldId);
+
+   geometry::initBoundaryHandling<FlagField_T>(*blocks, flagFieldId, boundariesConfig);
+   geometry::setNonBoundaryCellsToDomain<FlagField_T>(*blocks, flagFieldId, fluidFlagUID);
+
+   // TODO
+   // noSlip.fillFromFlagField<FlagField_T>( blocks, flagFieldId, FlagUID("NoSlip"), fluidFlagUID );
+
+   // create time loop
+   SweepTimeloop timeloop( blocks->getBlockStorage(), timesteps );
+
+   // create communication for PdfField
+   blockforest::communication::UniformBufferedScheme< CommunicationStencil_T > communication( blocks );
+   communication.addPackInfo( make_shared< lbm::PdfFieldPackInfo< LatticeModel_T > >( pdfFieldId ) );
+
+   // add LBM sweep and communication to time loop
+   timeloop.add() << BeforeFunction( communication, "communication" );
+                  //<< Sweep( walls, "Boundary Walls" );
+   timeloop.add() << Sweep( LatticeModel_T::Sweep( pdfFieldId ), "LB stream & collide" );
+
+   // LBM stability check
+   timeloop.addFuncAfterTimeStep( makeSharedFunctor( field::makeStabilityChecker< PdfField_T, FlagField_T >( walberlaEnv.config(), blocks, pdfFieldId,
+                                                                                                             flagFieldId, fluidFlagUID ) ),
+                                  "LBM stability check" );
+
+   // log remaining time
+   timeloop.addFuncAfterTimeStep( timing::RemainingTimeLogger( timeloop.getNrOfTimeSteps(), remainingTimeLoggerFrequency ), "remaining time logger" );
+
+   // add VTK output to time loop
+   lbm::VTKOutput< LatticeModel_T, FlagField_T >::addToTimeloop( timeloop, blocks, walberlaEnv.config(), pdfFieldId, flagFieldId, fluidFlagUID );
+
+   timeloop.run();
+
+   return EXIT_SUCCESS;
+}
+
+}
+
+int main(int argc, char ** argv){
+   return walberla::main(argc, argv);
+}
\ No newline at end of file

apps/tutorials/codegen/CMakeLists.txt

 # Code Generation Tutorials
 
 if( WALBERLA_BUILD_WITH_CODEGEN )
+
+    #   Tutorial 1: Heat Equation with pystencils
     walberla_generate_target_from_python( NAME CodegenHeatEquationKernel
         FILE HeatEquationKernel.py
         OUT_FILES HeatEquationKernel.cpp HeatEquationKernel.h )
@@ -8,4 +10,22 @@ if( WALBERLA_BUILD_WITH_CODEGEN )
     walberla_add_executable ( NAME 01_CodegenHeatEquation 
                               FILES 01_CodegenHeatEquation.cpp
                               DEPENDS blockforest core field stencil timeloop vtk pde CodegenHeatEquationKernel )
+
+    #   Tutorial 2: lbmpy Lattice Model Generation
+    walberla_generate_target_from_python( NAME LBMLatticeModelGenerationPython
+        FILE LBMLatticeModelGeneration.py
+        OUT_FILES   SRTLatticeModel.cpp SRTLatticeModel.h 
+                    SRTPackInfo.cpp SRTPackInfo.h
+                    SRTNoSlip.cpp SRTNoSlip.h
+                    CumulantMRTLatticeModel.cpp CumulantMRTLatticeModel.h 
+                    CumulantMRTPackInfo.cpp CumulantMRTPackInfo.h
+                    CumulantMRTNoSlip.cpp CumulantMRTNoSlip.h
+                    EntropicMRTLatticeModel.cpp EntropicMRTLatticeModel.h
+                    EntropicMRTPackInfo.cpp EntropicMRTPackInfo.h
+                    EntropicMRTNoSlip.cpp EntropicMRTNoSlip.h )
+
+    walberla_add_executable ( NAME 02_LBMLatticeModelGenerationApp 
+                    FILES 02_LBMLatticeModelGeneration.cpp
+                    DEPENDS blockforest core field stencil timeloop vtk pde LBMLatticeModelGenerationPython )
+
 endif()
\ No newline at end of file

apps/tutorials/codegen/LBMLatticeModelGeneration.py

+import sympy as sp
+import pystencils as ps
+
+from lbmpy.creationfunctions import create_lb_collision_rule, create_lb_update_rule
+from lbmpy.boundaries import NoSlip
+
+from pystencils_walberla import CodeGeneration, generate_pack_info_from_kernel
+from lbmpy_walberla import generate_lattice_model, generate_boundary
+
+#   =====================
+#   Common Parameters
+#   =====================
+
+STENCIL = 'D2Q9'
+OMEGA = sp.Symbol('omega')
+LAYOUT = 'zyxf'
+
+#   Optimization
+OPT = {'target': 'cpu', 'cse_global': True}
+
+#   Velocity Output Field
+vel_field = ps.fields("velocity(3): [2D]", layout=LAYOUT)
+OUTPUT = {'velocity': vel_field}
+
+#   ==================================================================================================
+#   Method Definitions, including collision rules, boundary handling and communication pack infos.
+#   ==================================================================================================
+
+
+#   SRT Method
+def build_srt_method(ctx):
+    srt_params = {'stencil': STENCIL,
+                  'method': 'srt',
+                  'relaxation_rate': OMEGA}
+
+    srt_collision_rule = create_lb_collision_rule(optimization=OPT, output=OUTPUT, **srt_params)
+    generate_lattice_model(ctx, "SRTLatticeModel", srt_collision_rule, field_layout=LAYOUT)
+
+    srt_update_rule = create_lb_update_rule(collision_rule=srt_collision_rule)
+    generate_pack_info_from_kernel(ctx, "SRTPackInfo", srt_update_rule)
+
+    generate_boundary(ctx, "SRTNoSlip", NoSlip(), srt_collision_rule.method)
+
+
+#   Cumulant MRT Method
+def build_cumulant_method(ctx):
+    mrt_cumulant_params = {'stencil': STENCIL,
+                           'method': 'mrt_raw',
+                           'relaxation_rates': [0, 0, 0, OMEGA, OMEGA, OMEGA, 1, 1, 1],
+                           'cumulant': True,
+                           'compressible': True}   # Incompressible cumulants not yet supported!
+
+    mrt_cumulant_collision_rule = create_lb_collision_rule(optimization=OPT, output=OUTPUT, **mrt_cumulant_params)
+    generate_lattice_model(ctx, "CumulantMRTLatticeModel", mrt_cumulant_collision_rule, field_layout=LAYOUT)
+
+    mrt_cumulant_update_rule = create_lb_update_rule(collision_rule=mrt_cumulant_collision_rule)
+    generate_pack_info_from_kernel(ctx, "CumulantMRTPackInfo", mrt_cumulant_update_rule)
+
+    generate_boundary(ctx, "CumulantMRTNoSlip", NoSlip(), mrt_cumulant_collision_rule.method)
+
+
+#   Orthogonal MRT Method with entropy constraint
+def build_entropic_method(ctx):
+    omega_f = sp.Symbol('omega_f')
+
+    mrt_entropic_params = {'stencil': STENCIL,
+                           'method': 'mrt',
+                           'relaxation_rates': [OMEGA, OMEGA, omega_f, omega_f],
+                           'entropic': True,
+                           'compressible': True}    # Entropic models only implemented with pdfs centered around 1
+
+    mrt_entropic_collision_rule = create_lb_collision_rule(optimization=OPT, output=OUTPUT, **mrt_entropic_params)
+    generate_lattice_model(ctx, "EntropicMRTLatticeModel", mrt_entropic_collision_rule, field_layout=LAYOUT)
+
+    mrt_entropic_update_rule = create_lb_update_rule(collision_rule=mrt_entropic_collision_rule)
+    generate_pack_info_from_kernel(ctx, "EntropicMRTPackInfo", mrt_entropic_update_rule)
+
+    generate_boundary(ctx, "EntropicMRTNoSlip", NoSlip(), mrt_entropic_collision_rule.method)
+
+#   ================================
+#   Main Function
+#   ================================
+
+
+if __name__ == "__main__":
+    #   All code generation must happen within one context, and all files specified in
+    #   CMakeLists.txt must be generated therein.
+    with CodeGeneration() as ctx:
+        build_srt_method(ctx)
+        build_cumulant_method(ctx)
+        build_entropic_method(ctx)