cg-multigrid-single-threaded.py

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import os, sys
import argparse
import peano4.api
import numpy as np
import mghype
 
print( """
 
Peano 4 multigrid solver using Continuous Galerkin
 
@author 2022 Sean Baccas, Dmitry Nikolaenko, Tobias Weinzierl
 
""")
 
parser = argparse.ArgumentParser(description='Multigrid - Poisson solver')
parser.add_argument("-j",   "--parallel-builds",    dest="j",              type=int, default=-1, help="Parallel builds" )
parser.add_argument("-pt",   "--plot-sweep",     dest="plot_after_each_mesh_sweep", action="store_true", default=False, help="Plot after each timestep. By default (False) we plot after initialisation and at the end" )
parser.add_argument("-pd",  "--peano-dir",          dest="peanodir",       default="../../../../", help="Peano4 directory" )
parser.add_argument("-v",   "--verbose",            dest="verbose",        action="store_true", default=False, help="Verbose")
parser.add_argument("-d",   "--dimensions",         dest="dimensions",     type=int, default=2, help="Dimensions")
parser.add_argument("-c",   "--coarse-level",       dest="coarsest_level", type=int, default=0, help="coarsest_level")
parser.add_argument("-meshsize",  "--meshsize",     dest="meshsize",       default=0.3, help="Mesh size")
parser.add_argument("-m",   "--mode",               dest="mode",           choices=["release","stats","asserts", "trace"], required=True, help="Pick build type" )
args = parser.parse_args()
 
project = mghype.matrixfree.api.Project( project_name = "CollocatedMG", 
                              namespace = [ "tests", "multigrid", "matrixfree", "poisson" ]
                                )
 
 
correction_equation_matrices = mghype.api.matrixgenerators.DLinearMassIdentity(
  dimensions = args.dimensions,
  poly_degree = 1,
  unknowns_per_node = 1
)
 
finest_level_matrices = mghype.api.matrixgenerators.DLinear(
  dimensions = args.dimensions,
  unknowns_per_node = 1
)
 
intergridOperators = mghype.api.matrixgenerators.blockmatrix.IntergridOperatorsH()
 
system_matrix, system_matrix_scaling = finest_level_matrices.get_cell_system_matrix_for_laplacian()
mass_matrix,   mass_matrix_scaling   = finest_level_matrices.get_cell_mass_matrix()
 
correction_matrix, correction_matrix_scaling = correction_equation_matrices.get_cell_mass_matrix()
 
solver = mghype.matrixfree.solvers.api.CollocatedMGSingleThreaded("CollocatedMG",
                                                    1,
                                                    args.dimensions,
                                                    args.meshsize,
                                                    args.meshsize,
                                                    local_assembly_matrix = system_matrix,
                                                    local_assembly_matrix_scaling=system_matrix_scaling,
                                                    mass_matrix = mass_matrix,
                                                    mass_matrix_scaling = mass_matrix_scaling,
                                                    correction_matrix = correction_matrix,
                                                    correction_matrix_scaling = correction_matrix_scaling,
                                                    solver_tolerance=0.01,
                                                    pre_smoothing_steps =5,
                                                    post_smoothing_steps=5,
                                                    restriction_matrix=intergridOperators.restriction(),
                                                    prolongation_matrix=intergridOperators.prolongation(),
                                                    descend_order=0,
                                                    coarsest_level=args.coarsest_level
                                                    )
 
project.add_solver(solver)
 
#
# Configure build
#
if args.mode=="release":
  build_mode = peano4.api.output.CompileMode.RELEASE
if args.mode=="stats":
  build_mode = peano4.api.output.CompileMode.STATS
if args.mode=="asserts":
  build_mode = peano4.api.output.CompileMode.ASSERTS
if args.mode=="trace":
  build_mode = peano4.api.output.CompileMode.TRACE
 
cube_size = 1.0
project.set_global_simulation_parameters(
  dimensions            = args.dimensions,
  offset                = [ 0.0       for _ in range(args.dimensions) ],
  domain_size           = [ cube_size for _ in range(args.dimensions) ],
  plot_after_each_mesh_sweep       = args.plot_after_each_mesh_sweep,
  max_iterations                   = 2000
)
 
'''
The first attempt to parallelise this code was a failure. So we comment out the load balancing.
'''
# project.set_load_balancing( "toolbox::loadbalancing::strategies::SpreadOutOnceGridStagnates", "new ::exahype2::LoadBalancingConfiguration(0.9, 0, false, 8, 50)" )
 
project.set_Peano4_installation( args.peanodir, build_mode )
 
peano4_project = project.generate_Peano4_project(args.verbose)
peano4_project.output.makefile.add_cpp_file( "Scenario.cpp" )
peano4_project.generate()
 
os.system( "make clean" )
if args.j>0:
  os.system( "make -j{}".format(args.j) )
else:
  os.system( "make -j$(nproc --all)" )
  
print("Done")