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solverforge_solver/heuristic/selector/
sublist_swap.rs

1//! Public static adapter for the canonical streamed sublist-swap cursor.
2
3use std::fmt::Debug;
4use std::marker::PhantomData;
5
6use solverforge_core::domain::PlanningSolution;
7use solverforge_scoring::Director;
8
9use crate::heuristic::r#move::SublistSwapMove;
10use crate::list_placement::selected_segment_allows;
11
12use super::list_kernel::{
13    NativeWindowEmitter, SelectedListOwners, SublistSwapCursor, STATIC_SUBLIST_SWAP_ENTITY_SALT,
14};
15
16use super::entity::EntitySelector;
17use super::list_support::collect_selected_entities;
18use super::move_selector::{
19    CandidateId, MoveCandidateRef, MoveCursor, MoveSelector, MoveStreamContext,
20};
21use super::sublist_support::{count_intra_sublist_swap_moves_for_len, count_sublist_segments};
22
23pub struct SublistSwapMoveSelector<S, V, ES> {
24    entity_selector: ES,
25    min_sublist_size: usize,
26    max_sublist_size: usize,
27    list_len: fn(&S, usize) -> usize,
28    list_get: fn(&S, usize, usize) -> Option<V>,
29    sublist_remove: fn(&mut S, usize, usize, usize) -> Vec<V>,
30    sublist_insert: fn(&mut S, usize, usize, Vec<V>),
31    element_owner_fn: Option<fn(&S, &V) -> Option<usize>>,
32    variable_name: &'static str,
33    descriptor_index: usize,
34    _phantom: PhantomData<(fn() -> S, fn() -> V)>,
35}
36
37pub struct SublistSwapMoveCursor<S, V>
38where
39    S: PlanningSolution,
40    V: Clone + PartialEq + Send + Sync + Debug + 'static,
41{
42    inner: SublistSwapCursor<S, NativeWindowEmitter<S, V>>,
43}
44
45impl<S, V> SublistSwapMoveCursor<S, V>
46where
47    S: PlanningSolution,
48    V: Clone + PartialEq + Send + Sync + Debug + 'static,
49{
50    fn new(inner: SublistSwapCursor<S, NativeWindowEmitter<S, V>>) -> Self {
51        Self { inner }
52    }
53}
54
55impl<S, V> MoveCursor<S, SublistSwapMove<S, V>> for SublistSwapMoveCursor<S, V>
56where
57    S: PlanningSolution,
58    V: Clone + PartialEq + Send + Sync + Debug + 'static,
59{
60    fn next_candidate(&mut self, solution: &S) -> Option<CandidateId> {
61        self.inner.next_candidate(solution)
62    }
63    fn candidate(&self, id: CandidateId) -> Option<MoveCandidateRef<'_, S, SublistSwapMove<S, V>>> {
64        self.inner.candidate(id)
65    }
66    fn take_candidate(&mut self, id: CandidateId) -> SublistSwapMove<S, V> {
67        self.inner.take_candidate(id)
68    }
69    fn next_owned_candidate(&mut self, solution: &S) -> Option<SublistSwapMove<S, V>> {
70        self.inner.next_owned_candidate(solution)
71    }
72    fn next_owned_candidate_matching(
73        &mut self,
74        solution: &S,
75        predicate: for<'a> fn(MoveCandidateRef<'a, S, SublistSwapMove<S, V>>) -> bool,
76    ) -> Option<SublistSwapMove<S, V>> {
77        self.inner
78            .next_owned_candidate_matching(solution, predicate)
79    }
80    fn release_candidate(&mut self, id: CandidateId) -> bool {
81        self.inner.release_candidate(id)
82    }
83}
84
85impl<S, V: Debug, ES: Debug> Debug for SublistSwapMoveSelector<S, V, ES> {
86    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
87        f.debug_struct("SublistSwapMoveSelector")
88            .field("entity_selector", &self.entity_selector)
89            .field("min_sublist_size", &self.min_sublist_size)
90            .field("max_sublist_size", &self.max_sublist_size)
91            .field("variable_name", &self.variable_name)
92            .field("descriptor_index", &self.descriptor_index)
93            .finish()
94    }
95}
96
97impl<S, V, ES> SublistSwapMoveSelector<S, V, ES> {
98    #[allow(clippy::too_many_arguments)]
99    pub fn new(
100        entity_selector: ES,
101        min_sublist_size: usize,
102        max_sublist_size: usize,
103        list_len: fn(&S, usize) -> usize,
104        list_get: fn(&S, usize, usize) -> Option<V>,
105        sublist_remove: fn(&mut S, usize, usize, usize) -> Vec<V>,
106        sublist_insert: fn(&mut S, usize, usize, Vec<V>),
107        variable_name: &'static str,
108        descriptor_index: usize,
109    ) -> Self {
110        assert!(min_sublist_size >= 1, "min_sublist_size must be at least 1");
111        assert!(
112            max_sublist_size >= min_sublist_size,
113            "max_sublist_size must be >= min_sublist_size"
114        );
115        Self {
116            entity_selector,
117            min_sublist_size,
118            max_sublist_size,
119            list_len,
120            list_get,
121            sublist_remove,
122            sublist_insert,
123            element_owner_fn: None,
124            variable_name,
125            descriptor_index,
126            _phantom: PhantomData,
127        }
128    }
129
130    pub fn with_element_owner_fn(
131        mut self,
132        element_owner_fn: Option<fn(&S, &V) -> Option<usize>>,
133    ) -> Self {
134        self.element_owner_fn = element_owner_fn;
135        self
136    }
137}
138
139impl<S, V, ES> MoveSelector<S, SublistSwapMove<S, V>> for SublistSwapMoveSelector<S, V, ES>
140where
141    S: PlanningSolution,
142    V: Clone + PartialEq + Send + Sync + Debug + 'static,
143    ES: EntitySelector<S>,
144{
145    type Cursor<'a>
146        = SublistSwapMoveCursor<S, V>
147    where
148        Self: 'a;
149
150    fn open_cursor<'a, D: Director<S>>(&'a self, score_director: &D) -> Self::Cursor<'a> {
151        self.open_cursor_with_context(score_director, MoveStreamContext::default())
152    }
153
154    fn open_cursor_with_context<'a, D: Director<S>>(
155        &'a self,
156        score_director: &D,
157        context: MoveStreamContext,
158    ) -> Self::Cursor<'a> {
159        let mut selected =
160            collect_selected_entities(&self.entity_selector, score_director, self.list_len);
161        selected.apply_stream_order(
162            context,
163            STATIC_SUBLIST_SWAP_ENTITY_SALT ^ self.descriptor_index as u64,
164        );
165        let owner_restrictions = crate::list_placement::selected_owner_restrictions(
166            self.element_owner_fn,
167            score_director.working_solution(),
168            score_director
169                .entity_count(self.descriptor_index)
170                .unwrap_or(0),
171            &selected.entities,
172            &selected.route_lens,
173            self.list_get,
174        );
175        let owners = SelectedListOwners::from_selected_restrictions(owner_restrictions);
176        SublistSwapMoveCursor::new(SublistSwapCursor::new(
177            NativeWindowEmitter::new(
178                self.list_len,
179                self.list_get,
180                self.sublist_remove,
181                self.sublist_insert,
182                self.variable_name,
183                self.descriptor_index,
184            ),
185            selected.entities,
186            selected.route_lens,
187            context,
188            self.min_sublist_size,
189            self.max_sublist_size,
190            owners,
191            self.descriptor_index,
192        ))
193    }
194
195    fn size<D: Director<S>>(&self, score_director: &D) -> usize {
196        let selected =
197            collect_selected_entities(&self.entity_selector, score_director, self.list_len);
198        let Some(owner_restrictions) = crate::list_placement::selected_owner_restrictions(
199            self.element_owner_fn,
200            score_director.working_solution(),
201            score_director
202                .entity_count(self.descriptor_index)
203                .unwrap_or(0),
204            &selected.entities,
205            &selected.route_lens,
206            self.list_get,
207        ) else {
208            return unfiltered_sublist_swap_size(
209                &selected.route_lens,
210                self.min_sublist_size,
211                self.max_sublist_size,
212            );
213        };
214        if owner_restrictions.is_fixed_to_current() {
215            return selected
216                .route_lens
217                .iter()
218                .map(|&route_len| {
219                    count_intra_sublist_swap_moves_for_len(
220                        route_len,
221                        self.min_sublist_size,
222                        self.max_sublist_size,
223                    )
224                })
225                .sum();
226        }
227        let owners = owner_restrictions
228            .mixed()
229            .expect("non-fixed owner restrictions retain their matrix");
230        let mut count = 0;
231        for (first_idx, &first_entity) in selected.entities.iter().enumerate() {
232            let first_len = selected.route_lens[first_idx];
233            for first_start in 0..first_len {
234                let first_max = self.max_sublist_size.min(first_len - first_start);
235                for first_size in self.min_sublist_size..=first_max {
236                    let first_end = first_start + first_size;
237                    for (second_idx, &second_entity) in
238                        selected.entities.iter().enumerate().skip(first_idx)
239                    {
240                        let second_len = selected.route_lens[second_idx];
241                        for second_start in 0..second_len {
242                            let second_max = self.max_sublist_size.min(second_len - second_start);
243                            for second_size in self.min_sublist_size..=second_max {
244                                let second_end = second_start + second_size;
245                                if first_idx == second_idx
246                                    && (second_start < first_end
247                                        || (first_start == second_start && first_end == second_end))
248                                {
249                                    continue;
250                                }
251                                let allowed = if first_entity == second_entity {
252                                    selected_segment_allows(
253                                        owners,
254                                        first_idx,
255                                        first_start,
256                                        first_end,
257                                        first_entity,
258                                    ) && selected_segment_allows(
259                                        owners,
260                                        second_idx,
261                                        second_start,
262                                        second_end,
263                                        first_entity,
264                                    )
265                                } else {
266                                    selected_segment_allows(
267                                        owners,
268                                        first_idx,
269                                        first_start,
270                                        first_end,
271                                        second_entity,
272                                    ) && selected_segment_allows(
273                                        owners,
274                                        second_idx,
275                                        second_start,
276                                        second_end,
277                                        first_entity,
278                                    )
279                                };
280                                if allowed {
281                                    count += 1;
282                                }
283                            }
284                        }
285                    }
286                }
287            }
288        }
289        count
290    }
291}
292
293fn unfiltered_sublist_swap_size(
294    route_lens: &[usize],
295    min_sublist_size: usize,
296    max_sublist_size: usize,
297) -> usize {
298    let segment_counts = route_lens
299        .iter()
300        .map(|&route_len| count_sublist_segments(route_len, min_sublist_size, max_sublist_size))
301        .collect::<Vec<_>>();
302    let intra = route_lens
303        .iter()
304        .map(|&route_len| {
305            count_intra_sublist_swap_moves_for_len(route_len, min_sublist_size, max_sublist_size)
306        })
307        .sum::<usize>();
308    let inter = (0..route_lens.len())
309        .flat_map(|left| (left + 1..route_lens.len()).map(move |right| (left, right)))
310        .map(|(left, right)| segment_counts[left] * segment_counts[right])
311        .sum::<usize>();
312    intra + inter
313}