Coverage for pySDC/tutorial/step_7/E_pySDC_with_Firedrake.py: 0%
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1"""
2Simple example running a forced heat equation in Firedrake.
4The function `setup` generates the description and controller_params dictionaries needed to run SDC with diagonal preconditioner.
5This proceeds very similar to earlier tutorials. The interesting part of this tutorial is rather in the problem class.
6See `pySDC/implementations/problem_classes/HeatFiredrake` for an easy example of how to use Firedrake within pySDC.
8The script allows to run in three different ways. Use
9 - `python E_pySDC_with_Firedrake.py` for single-level serial SDC
10 - `mpiexec -np 3 E_pySDC_with_Firedrake --useMPIsweeper` for single-level MPI-parallel diagonal SDC
11 - `python E_pySDC_with_Firedrake --ML` for three-level serial SDC
13You should notice that speedup of MPI parallelisation is quite good and that, while multi-level SDC reduces the number
14of SDC iterations quite a bit, it does not reduce time to solution in this case. This is partly due to more solvers being
15constructed when using coarse levels. Also, we do not claim to have found the best parameters, though. This is just an
16example to demonstrate how to use it.
17"""
19import numpy as np
20from mpi4py import MPI
23def setup(useMPIsweeper):
24 """
25 Helper routine to set up parameters
27 Returns:
28 description and controller_params parameter dictionaries
29 """
30 from pySDC.implementations.problem_classes.HeatFiredrake import Heat1DForcedFiredrake
31 from pySDC.implementations.sweeper_classes.imex_1st_order import imex_1st_order
32 from pySDC.implementations.sweeper_classes.imex_1st_order_MPI import imex_1st_order_MPI
33 from pySDC.implementations.hooks.log_errors import LogGlobalErrorPostRun
34 from pySDC.implementations.hooks.log_work import LogWork
35 from pySDC.helpers.firedrake_ensemble_communicator import FiredrakeEnsembleCommunicator
37 # setup space-time parallelism via ensemble for Firedrake, see https://www.firedrakeproject.org/firedrake/parallelism.html
38 num_nodes = 3
39 ensemble = FiredrakeEnsembleCommunicator(MPI.COMM_WORLD, max([MPI.COMM_WORLD.size // num_nodes, 1]))
41 level_params = dict()
42 level_params['restol'] = 5e-10
43 level_params['dt'] = 0.2
45 step_params = dict()
46 step_params['maxiter'] = 20
48 sweeper_params = dict()
49 sweeper_params['quad_type'] = 'RADAU-RIGHT'
50 sweeper_params['num_nodes'] = num_nodes
51 sweeper_params['QI'] = 'MIN-SR-S'
52 sweeper_params['QE'] = 'PIC'
53 sweeper_params['comm'] = ensemble
55 problem_params = dict()
56 problem_params['nu'] = 0.1
57 problem_params['n'] = 128
58 problem_params['c'] = 1.0
59 problem_params['comm'] = ensemble.space_comm
61 controller_params = dict()
62 controller_params['logger_level'] = 15 if MPI.COMM_WORLD.rank == 0 else 30
63 controller_params['hook_class'] = [LogGlobalErrorPostRun, LogWork]
65 description = dict()
66 description['problem_class'] = Heat1DForcedFiredrake
67 description['problem_params'] = problem_params
68 description['sweeper_class'] = imex_1st_order_MPI if useMPIsweeper else imex_1st_order
69 description['sweeper_params'] = sweeper_params
70 description['level_params'] = level_params
71 description['step_params'] = step_params
73 return description, controller_params
76def setup_ML():
77 """
78 Helper routine to set up parameters
80 Returns:
81 description and controller_params parameter dictionaries
82 """
83 from pySDC.implementations.problem_classes.HeatFiredrake import Heat1DForcedFiredrake
84 from pySDC.implementations.sweeper_classes.imex_1st_order import imex_1st_order
85 from pySDC.implementations.sweeper_classes.imex_1st_order_MPI import imex_1st_order_MPI
86 from pySDC.implementations.transfer_classes.TransferFiredrakeMesh import MeshToMeshFiredrake
87 from pySDC.implementations.hooks.log_errors import LogGlobalErrorPostRun
88 from pySDC.implementations.hooks.log_work import LogWork
89 from pySDC.helpers.firedrake_ensemble_communicator import FiredrakeEnsembleCommunicator
91 level_params = dict()
92 level_params['restol'] = 5e-10
93 level_params['dt'] = 0.2
95 step_params = dict()
96 step_params['maxiter'] = 20
98 sweeper_params = dict()
99 sweeper_params['quad_type'] = 'RADAU-RIGHT'
100 sweeper_params['num_nodes'] = 3
101 sweeper_params['QI'] = 'MIN-SR-S'
102 sweeper_params['QE'] = 'PIC'
104 problem_params = dict()
105 problem_params['nu'] = 0.1
106 problem_params['n'] = [128, 32, 4]
107 problem_params['c'] = 1.0
109 base_transfer_params = dict()
110 base_transfer_params['finter'] = True
112 controller_params = dict()
113 controller_params['logger_level'] = 15 if MPI.COMM_WORLD.rank == 0 else 30
114 controller_params['hook_class'] = [LogGlobalErrorPostRun, LogWork]
116 description = dict()
117 description['problem_class'] = Heat1DForcedFiredrake
118 description['problem_params'] = problem_params
119 description['sweeper_class'] = imex_1st_order
120 description['sweeper_params'] = sweeper_params
121 description['level_params'] = level_params
122 description['step_params'] = step_params
123 description['space_transfer_class'] = MeshToMeshFiredrake
124 description['base_transfer_params'] = base_transfer_params
126 return description, controller_params
129def runHeatFiredrake(useMPIsweeper=False, ML=False):
130 """
131 Run the example defined by the above parameters
132 """
133 from pySDC.implementations.controller_classes.controller_nonMPI import controller_nonMPI
134 from pySDC.helpers.stats_helper import get_sorted
136 Tend = 1.0
137 t0 = 0.0
139 if ML:
140 assert not useMPIsweeper, 'MPI parallel diagonal SDC and ML SDC are not compatible at the moment'
141 description, controller_params = setup_ML()
142 else:
143 description, controller_params = setup(useMPIsweeper)
145 controller = controller_nonMPI(num_procs=1, controller_params=controller_params, description=description)
147 # get initial values
148 P = controller.MS[0].levels[0].prob
149 uinit = P.u_exact(0.0)
151 # call main function to get things done...
152 uend, stats = controller.run(u0=uinit, t0=t0, Tend=Tend)
154 # see what we get
155 error = get_sorted(stats, type='e_global_post_run')
156 work_solver_setup = get_sorted(stats, type='work_solver_setup')
157 work_solves = get_sorted(stats, type='work_solves')
158 work_rhs = get_sorted(stats, type='work_rhs')
159 niter = get_sorted(stats, type='niter')
161 tot_iter = np.sum([me[1] for me in niter])
162 tot_solver_setup = np.sum([me[1] for me in work_solver_setup])
163 tot_solves = np.sum([me[1] for me in work_solves])
164 tot_rhs = np.sum([me[1] for me in work_rhs])
166 time_rank = description["sweeper_params"]["comm"].rank if useMPIsweeper else 0
167 print(
168 f'Finished with error {error[0][1]:.2e}. Used {tot_iter} SDC iterations, with {tot_solver_setup} solver setups, {tot_solves} solves and {tot_rhs} right hand side evaluations on the finest level of time task {time_rank}.'
169 )
171 # do tests that we got the same as last time
172 n_nodes = 1 if useMPIsweeper else description['sweeper_params']['num_nodes']
173 assert error[0][1] < 2e-8
174 assert tot_iter == 10 if ML else 29
175 assert tot_solver_setup == n_nodes
176 assert tot_solves == n_nodes * tot_iter
177 assert tot_rhs == n_nodes * tot_iter + (n_nodes + 1) * len(niter)
180if __name__ == "__main__":
181 from argparse import ArgumentParser
183 parser = ArgumentParser()
184 parser.add_argument(
185 '--ML',
186 help='Whether you want to run multi-level',
187 default=False,
188 required=False,
189 action='store_const',
190 const=True,
191 )
192 parser.add_argument(
193 '--useMPIsweeper',
194 help='Whether you want to use MPI parallel diagonal SDC',
195 default=False,
196 required=False,
197 action='store_const',
198 const=True,
199 )
201 args = parser.parse_args()
203 runHeatFiredrake(**vars(args))