Line data Source code
1 0 : // Distributed under the MIT License.
2 : // See LICENSE.txt for details.
3 :
4 : #pragma once
5 :
6 : #include <algorithm>
7 : #include <cstddef>
8 : #include <deque>
9 : #include <iterator>
10 : #include <optional>
11 : #include <tuple>
12 : #include <type_traits>
13 : #include <utility>
14 :
15 : #include "DataStructures/DataBox/DataBox.hpp"
16 : #include "DataStructures/DataBox/PrefixHelpers.hpp"
17 : #include "DataStructures/DataBox/Prefixes.hpp"
18 : #include "DataStructures/DataVector.hpp"
19 : #include "DataStructures/TaggedTuple.hpp"
20 : #include "Domain/Structure/Direction.hpp"
21 : #include "Domain/Structure/DirectionalId.hpp"
22 : #include "Domain/Structure/DirectionalIdMap.hpp"
23 : #include "Domain/Structure/Element.hpp"
24 : #include "Domain/Structure/ElementId.hpp"
25 : #include "Domain/Tags.hpp"
26 : #include "Evolution/DgSubcell/Actions/Labels.hpp"
27 : #include "Evolution/DgSubcell/ActiveGrid.hpp"
28 : #include "Evolution/DgSubcell/GhostData.hpp"
29 : #include "Evolution/DgSubcell/Mesh.hpp"
30 : #include "Evolution/DgSubcell/NeighborRdmpAndVolumeData.hpp"
31 : #include "Evolution/DgSubcell/Projection.hpp"
32 : #include "Evolution/DgSubcell/RdmpTci.hpp"
33 : #include "Evolution/DgSubcell/RdmpTciData.hpp"
34 : #include "Evolution/DgSubcell/SubcellOptions.hpp"
35 : #include "Evolution/DgSubcell/Tags/ActiveGrid.hpp"
36 : #include "Evolution/DgSubcell/Tags/Coordinates.hpp"
37 : #include "Evolution/DgSubcell/Tags/DataForRdmpTci.hpp"
38 : #include "Evolution/DgSubcell/Tags/DidRollback.hpp"
39 : #include "Evolution/DgSubcell/Tags/GhostDataForReconstruction.hpp"
40 : #include "Evolution/DgSubcell/Tags/Interpolators.hpp"
41 : #include "Evolution/DgSubcell/Tags/Mesh.hpp"
42 : #include "Evolution/DgSubcell/Tags/MeshForGhostData.hpp"
43 : #include "Evolution/DgSubcell/Tags/SubcellOptions.hpp"
44 : #include "Evolution/DgSubcell/Tags/TciStatus.hpp"
45 : #include "Evolution/DiscontinuousGalerkin/InboxTags.hpp"
46 : #include "Evolution/DiscontinuousGalerkin/OnlyDgBlockIds.hpp"
47 : #include "NumericalAlgorithms/Interpolation/IrregularInterpolant.hpp"
48 : #include "NumericalAlgorithms/Spectral/Mesh.hpp"
49 : #include "Parallel/AlgorithmExecution.hpp"
50 : #include "Parallel/GlobalCache.hpp"
51 : #include "ParallelAlgorithms/Actions/Goto.hpp"
52 : #include "Time/Actions/SelfStartActions.hpp"
53 : #include "Time/History.hpp"
54 : #include "Utilities/Algorithm.hpp"
55 : #include "Utilities/ContainerHelpers.hpp"
56 : #include "Utilities/ErrorHandling/Assert.hpp"
57 : #include "Utilities/TMPL.hpp"
58 :
59 : /// \cond
60 : namespace Tags {
61 : template <typename Tag>
62 : struct HistoryEvolvedVariables;
63 : struct TimeStepId;
64 : } // namespace Tags
65 : /// \endcond
66 :
67 : namespace evolution::dg::subcell::Actions {
68 : /*!
69 : * \brief Run the troubled-cell indicator on the candidate solution and perform
70 : * the time step rollback if needed.
71 : *
72 : * Elements that cannot use subcell (e.g. non-hypercube topology or DG-only
73 : * blocks) skip the TCI entirely, set the TCI decision to 0, clear ghost data,
74 : * and continue.
75 : *
76 : * Interior cells are marked as troubled if
77 : * `subcell_options.always_use_subcells()` is `true`, or if either the RDMP
78 : * troubled-cell indicator (TCI) or the TciMutator reports the cell is
79 : * troubled. Exterior cells are marked as troubled only if
80 : * `Metavariables::SubcellOptions::subcell_enabled_at_external_boundary` is
81 : * `true`.
82 : *
83 : * The troubled-cell indicator (TCI) given by the mutator `TciMutator` can
84 : * mutate tags in the DataBox, but should do so cautiously. The main reason that
85 : * this is a mutator is because primitive variables, such as the pressure, are
86 : * used to check if the solution is physical. In the relativistic case, even
87 : * just whether or not the primitive variables can be recovered is used as a
88 : * condition. Note that the evolved variables are projected to the subcells
89 : * _after_ the TCI is called and marks the cell as troubled.
90 : *
91 : * After rollback, the subcell scheme must project the DG boundary corrections
92 : * \f$G\f$ to the subcells for the scheme to be conservative. The subcell
93 : * actions know if a rollback was done because the local mortar data would
94 : * already be computed.
95 : */
96 : template <typename TciMutator>
97 1 : struct TciAndRollback {
98 : template <typename DbTags, typename... InboxTags, typename Metavariables,
99 : typename ArrayIndex, typename ActionList,
100 : typename ParallelComponent, size_t Dim = Metavariables::volume_dim>
101 0 : static Parallel::iterable_action_return_t apply(
102 : db::DataBox<DbTags>& box,
103 : const tuples::TaggedTuple<InboxTags...>& /*inboxes*/,
104 : const Parallel::GlobalCache<Metavariables>& /*cache*/,
105 : const ArrayIndex& /*array_index*/, const ActionList /*meta*/,
106 : const ParallelComponent* const /*meta*/) {
107 : static_assert(
108 : tmpl::count_if<
109 : ActionList,
110 : std::is_same<tmpl::_1, tmpl::pin<TciAndRollback>>>::value == 1,
111 : "Must have the TciAndRollback action exactly once in the action list "
112 : "of a phase.");
113 : static_assert(
114 : tmpl::count_if<
115 : ActionList,
116 : std::is_same<tmpl::_1,
117 : tmpl::pin<::Actions::Label<
118 : evolution::dg::subcell::Actions::Labels::
119 : BeginSubcellAfterDgRollback>>>>::value == 1,
120 : "Must have the BeginSubcellAfterDgRollback label exactly once in the "
121 : "action list of a phase.");
122 :
123 : using variables_tag = typename Metavariables::system::variables_tag;
124 :
125 : const ActiveGrid active_grid = db::get<Tags::ActiveGrid>(box);
126 : ASSERT(active_grid == ActiveGrid::Dg,
127 : "Must be using DG when calling TciAndRollback action.");
128 :
129 : const Element<Dim>& element = db::get<::domain::Tags::Element<Dim>>(box);
130 : const bool cell_has_external_boundary =
131 : not element.external_boundaries().empty();
132 :
133 : constexpr bool subcell_enabled_at_external_boundary =
134 : Metavariables::SubcellOptions::subcell_enabled_at_external_boundary;
135 : const Mesh<Dim>& dg_mesh = db::get<::domain::Tags::Mesh<Dim>>(box);
136 : const Mesh<Dim>& subcell_mesh = db::get<Tags::Mesh<Dim>>(box);
137 :
138 : const SubcellOptions& subcell_options =
139 : db::get<Tags::SubcellOptions<Dim>>(box);
140 : const std::vector<size_t>& only_dg_block_ids =
141 : db::get<evolution::dg::Tags::OnlyDgBlockIds<Dim>>(box);
142 : bool cell_is_troubled =
143 : subcell_options.always_use_subcells() or
144 : (subcell_options.use_halo() and [&box]() -> bool {
145 : for (const auto& [_, neighbor_decision] :
146 : db::get<evolution::dg::subcell::Tags::NeighborTciDecisions<Dim>>(
147 : box)) {
148 : if (neighbor_decision != 0) {
149 : return true;
150 : }
151 : }
152 : return false;
153 : }());
154 :
155 : const bool bordering_dg_block =
156 : evolution::dg::borders_only_dg_block(element, only_dg_block_ids);
157 :
158 : // Subcell is allowed in the element if 3 conditions are met:
159 : // (i) The DG mesh topology supports subcell
160 : // (ii) The current element block id is not marked as DG only
161 : // (iii) The current element is not bordering a DG only block.
162 : const bool subcell_allowed_in_element =
163 : fd::dg_mesh_supports_subcell(dg_mesh) and
164 : not alg::found(only_dg_block_ids, element.id().block_id()) and
165 : not bordering_dg_block;
166 :
167 : // Elements that can never use subcell (e.g. non-hypercube topology or
168 : // DG-only blocks) should skip the TCI entirely, since the TCI projects
169 : // to the subcell mesh which is unsupported for these elements.
170 : if (not subcell_allowed_in_element) {
171 : db::mutate<Tags::TciDecision,
172 : subcell::Tags::GhostDataForReconstruction<Dim>>(
173 : [](const gsl::not_null<int*> tci_decision_ptr,
174 : const auto neighbor_data_ptr) {
175 : *tci_decision_ptr = 0;
176 : neighbor_data_ptr->clear();
177 : },
178 : make_not_null(&box));
179 : return {Parallel::AlgorithmExecution::Continue, std::nullopt};
180 : }
181 :
182 : // The reason we pass in the persson_exponent explicitly instead of
183 : // leaving it to the user is because the value of the exponent that
184 : // should be used to decide if it is safe to switch back to DG should be
185 : // `persson_exponent+1` to prevent the code from rapidly switching back
186 : // and forth between DG and subcell. Rather than trying to enforce this
187 : // by documentation, the switching back to DG TCI gets passed in the
188 : // exponent it should use, and to keep the interface between the TCIs
189 : // consistent, we also pass the exponent in separately here.
190 : std::tuple<int, RdmpTciData> tci_result = db::mutate_apply<TciMutator>(
191 : make_not_null(&box), subcell_options.persson_exponent(), false);
192 :
193 : const int tci_decision = std::get<0>(tci_result);
194 : db::mutate<Tags::TciDecision>(
195 : [&tci_decision](const gsl::not_null<int*> tci_decision_ptr) {
196 : *tci_decision_ptr = tci_decision;
197 : },
198 : make_not_null(&box));
199 :
200 : cell_is_troubled |= (tci_decision != 0);
201 :
202 : // If either:
203 : //
204 : // 1. we are not allowed to do subcell in this block (handled by the
205 : // early return above)
206 : // 2. the element is at an outer boundary _and_ we aren't allowed to go
207 : // to subcell at an outer boundary.
208 : // 3. the cell is not troubled
209 : //
210 : // then we can remove the current neighbor data and update the RDMP TCI
211 : // data.
212 : if ((cell_has_external_boundary and
213 : not subcell_enabled_at_external_boundary) or
214 : not cell_is_troubled) {
215 : db::mutate<subcell::Tags::GhostDataForReconstruction<Dim>,
216 : subcell::Tags::DataForRdmpTci>(
217 : [&tci_result](const auto neighbor_data_ptr,
218 : const gsl::not_null<RdmpTciData*> rdmp_tci_data_ptr) {
219 : neighbor_data_ptr->clear();
220 : *rdmp_tci_data_ptr = std::move(std::get<1>(std::move(tci_result)));
221 : },
222 : make_not_null(&box));
223 : return {Parallel::AlgorithmExecution::Continue, std::nullopt};
224 : }
225 :
226 : db::mutate<variables_tag, ::Tags::HistoryEvolvedVariables<variables_tag>,
227 : Tags::ActiveGrid, Tags::DidRollback,
228 : subcell::Tags::GhostDataForReconstruction<Dim>>(
229 : [&dg_mesh, &element, &subcell_mesh](
230 : const auto active_vars_ptr, const auto active_history_ptr,
231 : const gsl::not_null<ActiveGrid*> active_grid_ptr,
232 : const gsl::not_null<bool*> did_rollback_ptr,
233 : const gsl::not_null<DirectionalIdMap<Dim, GhostData>*>
234 : ghost_data_ptr,
235 : const DirectionalIdMap<Dim, Mesh<Dim>>& meshes_for_ghost_data,
236 : const size_t ghost_zone_size,
237 : const DirectionalIdMap<Dim, std::optional<intrp::Irregular<Dim>>>&
238 : neighbor_dg_to_fd_interpolants) {
239 : ASSERT(active_history_ptr->size() > 0,
240 : "We cannot have an empty history when unwinding, that's just "
241 : "nutty. Did you call the action too early in the action "
242 : "list?");
243 : // Rollback u^{n+1}* to u^n (undoing the candidate solution).
244 : //
245 : // Note: strictly speaking, to be conservative this should project
246 : // uJ instead of u.
247 : *active_vars_ptr = fd::project(active_history_ptr->latest_value(),
248 : dg_mesh, subcell_mesh.extents());
249 :
250 : // Project the time stepper history to the subcells, excluding the
251 : // most recent inadmissible history.
252 : active_history_ptr->undo_latest();
253 : active_history_ptr->map_entries(
254 : [&dg_mesh, &subcell_mesh](const auto entry) {
255 : *entry = fd::project(*entry, dg_mesh, subcell_mesh.extents());
256 : });
257 : *active_grid_ptr = ActiveGrid::Subcell;
258 : *did_rollback_ptr = true;
259 : // Project the neighbor data we were sent for reconstruction since
260 : // the neighbor might have sent DG volume data instead of ghost data
261 : // in order to elide projections when they aren't necessary.
262 : for (const auto& [directional_element_id, mesh_for_ghost_data] :
263 : meshes_for_ghost_data) {
264 : evolution::dg::subcell::insert_or_update_neighbor_volume_data<
265 : false>(ghost_data_ptr,
266 : ghost_data_ptr->at(directional_element_id)
267 : .neighbor_ghost_data_for_reconstruction(),
268 : 0, directional_element_id, mesh_for_ghost_data, element,
269 : subcell_mesh, ghost_zone_size,
270 : neighbor_dg_to_fd_interpolants,
271 : typename Metavariables::SubcellOptions::GhostVariables::
272 : ghost_variables_tag_list{});
273 : }
274 :
275 : // Note: We do _not_ project the boundary history here because
276 : // that needs to be done at the lifting stage of the subcell
277 : // method, since we need to lift G+D instead of the ingredients
278 : // that go into G+D, which is what we would be projecting here.
279 : },
280 : make_not_null(&box),
281 : db::get<evolution::dg::subcell::Tags::MeshForGhostData<Dim>>(box),
282 : Metavariables::SubcellOptions::ghost_zone_size(box),
283 : db::get<
284 : evolution::dg::subcell::Tags::InterpolatorsFromNeighborDgToFd<Dim>>(
285 : box));
286 :
287 : if (UNLIKELY(db::get<::Tags::TimeStepId>(box).slab_number() < 0)) {
288 : // If we are doing self start, then we need to project the initial
289 : // guess to the subcells as well.
290 : //
291 : // Warning: this unfortunately needs to be kept in sync with the
292 : // self-start procedure.
293 : //
294 : // Note: if we switch to the subcells then we might have an
295 : // inconsistent
296 : // state between the primitive and conservative variables on the
297 : // subcells. The most correct thing is to re-compute the
298 : // primitive variables on the subcells, since projecting the
299 : // conservative variables is conservative.
300 : if constexpr (Metavariables::system::
301 : has_primitive_and_conservative_vars) {
302 : db::mutate<
303 : SelfStart::Tags::InitialValue<variables_tag>,
304 : SelfStart::Tags::InitialValue<
305 : typename Metavariables::system::primitive_variables_tag>>(
306 : [&dg_mesh, &subcell_mesh](const auto initial_vars_ptr,
307 : const auto initial_prim_vars_ptr) {
308 : // Note: for strict conservation, we need to project uJ
309 : // instead of just u.
310 : std::get<0>(*initial_vars_ptr) =
311 : fd::project(std::get<0>(*initial_vars_ptr), dg_mesh,
312 : subcell_mesh.extents());
313 : std::get<0>(*initial_prim_vars_ptr) =
314 : fd::project(std::get<0>(*initial_prim_vars_ptr), dg_mesh,
315 : subcell_mesh.extents());
316 : },
317 : make_not_null(&box));
318 : } else {
319 : db::mutate<SelfStart::Tags::InitialValue<variables_tag>>(
320 : [&dg_mesh, &subcell_mesh](const auto initial_vars_ptr) {
321 : // Note: for strict conservation, we need to project uJ
322 : // instead of just u.
323 : std::get<0>(*initial_vars_ptr) =
324 : fd::project(std::get<0>(*initial_vars_ptr), dg_mesh,
325 : subcell_mesh.extents());
326 : },
327 : make_not_null(&box));
328 : }
329 : }
330 :
331 : return {Parallel::AlgorithmExecution::Continue,
332 : tmpl::index_of<
333 : ActionList,
334 : ::Actions::Label<evolution::dg::subcell::Actions::Labels::
335 : BeginSubcellAfterDgRollback>>::value +
336 : 1};
337 : }
338 : };
339 : } // namespace evolution::dg::subcell::Actions
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