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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) -> Option<CandidateId> {
61        self.inner.next_candidate()
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) -> Option<SublistSwapMove<S, V>> {
70        self.inner.next_owned_candidate()
71    }
72    fn next_owned_candidate_matching(
73        &mut self,
74        predicate: for<'a> fn(MoveCandidateRef<'a, S, SublistSwapMove<S, V>>) -> bool,
75    ) -> Option<SublistSwapMove<S, V>> {
76        self.inner.next_owned_candidate_matching(predicate)
77    }
78    fn release_candidate(&mut self, id: CandidateId) -> bool {
79        self.inner.release_candidate(id)
80    }
81}
82
83impl<S, V> Iterator for SublistSwapMoveCursor<S, V>
84where
85    S: PlanningSolution,
86    V: Clone + PartialEq + Send + Sync + Debug + 'static,
87{
88    type Item = SublistSwapMove<S, V>;
89    fn next(&mut self) -> Option<Self::Item> {
90        self.next_owned_candidate()
91    }
92}
93
94impl<S, V: Debug, ES: Debug> Debug for SublistSwapMoveSelector<S, V, ES> {
95    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
96        f.debug_struct("SublistSwapMoveSelector")
97            .field("entity_selector", &self.entity_selector)
98            .field("min_sublist_size", &self.min_sublist_size)
99            .field("max_sublist_size", &self.max_sublist_size)
100            .field("variable_name", &self.variable_name)
101            .field("descriptor_index", &self.descriptor_index)
102            .finish()
103    }
104}
105
106impl<S, V, ES> SublistSwapMoveSelector<S, V, ES> {
107    #[allow(clippy::too_many_arguments)]
108    pub fn new(
109        entity_selector: ES,
110        min_sublist_size: usize,
111        max_sublist_size: usize,
112        list_len: fn(&S, usize) -> usize,
113        list_get: fn(&S, usize, usize) -> Option<V>,
114        sublist_remove: fn(&mut S, usize, usize, usize) -> Vec<V>,
115        sublist_insert: fn(&mut S, usize, usize, Vec<V>),
116        variable_name: &'static str,
117        descriptor_index: usize,
118    ) -> Self {
119        assert!(min_sublist_size >= 1, "min_sublist_size must be at least 1");
120        assert!(
121            max_sublist_size >= min_sublist_size,
122            "max_sublist_size must be >= min_sublist_size"
123        );
124        Self {
125            entity_selector,
126            min_sublist_size,
127            max_sublist_size,
128            list_len,
129            list_get,
130            sublist_remove,
131            sublist_insert,
132            element_owner_fn: None,
133            variable_name,
134            descriptor_index,
135            _phantom: PhantomData,
136        }
137    }
138
139    pub fn with_element_owner_fn(
140        mut self,
141        element_owner_fn: Option<fn(&S, &V) -> Option<usize>>,
142    ) -> Self {
143        self.element_owner_fn = element_owner_fn;
144        self
145    }
146}
147
148impl<S, V, ES> MoveSelector<S, SublistSwapMove<S, V>> for SublistSwapMoveSelector<S, V, ES>
149where
150    S: PlanningSolution,
151    V: Clone + PartialEq + Send + Sync + Debug + 'static,
152    ES: EntitySelector<S>,
153{
154    type Cursor<'a>
155        = SublistSwapMoveCursor<S, V>
156    where
157        Self: 'a;
158
159    fn open_cursor<'a, D: Director<S>>(&'a self, score_director: &D) -> Self::Cursor<'a> {
160        self.open_cursor_with_context(score_director, MoveStreamContext::default())
161    }
162
163    fn open_cursor_with_context<'a, D: Director<S>>(
164        &'a self,
165        score_director: &D,
166        context: MoveStreamContext,
167    ) -> Self::Cursor<'a> {
168        let mut selected =
169            collect_selected_entities(&self.entity_selector, score_director, self.list_len);
170        selected.apply_stream_order(
171            context,
172            STATIC_SUBLIST_SWAP_ENTITY_SALT ^ self.descriptor_index as u64,
173        );
174        let owner_restrictions = crate::list_placement::selected_owner_restrictions(
175            self.element_owner_fn,
176            score_director.working_solution(),
177            score_director
178                .entity_count(self.descriptor_index)
179                .unwrap_or(0),
180            &selected.entities,
181            &selected.route_lens,
182            self.list_get,
183        );
184        let owners = SelectedListOwners::from_selected_restrictions(owner_restrictions);
185        SublistSwapMoveCursor::new(SublistSwapCursor::new(
186            NativeWindowEmitter::new(
187                self.list_len,
188                self.list_get,
189                self.sublist_remove,
190                self.sublist_insert,
191                self.variable_name,
192                self.descriptor_index,
193            ),
194            selected.entities,
195            selected.route_lens,
196            context,
197            self.min_sublist_size,
198            self.max_sublist_size,
199            owners,
200            self.descriptor_index,
201        ))
202    }
203
204    fn size<D: Director<S>>(&self, score_director: &D) -> usize {
205        let selected =
206            collect_selected_entities(&self.entity_selector, score_director, self.list_len);
207        let Some(owner_restrictions) = crate::list_placement::selected_owner_restrictions(
208            self.element_owner_fn,
209            score_director.working_solution(),
210            score_director
211                .entity_count(self.descriptor_index)
212                .unwrap_or(0),
213            &selected.entities,
214            &selected.route_lens,
215            self.list_get,
216        ) else {
217            return unfiltered_sublist_swap_size(
218                &selected.route_lens,
219                self.min_sublist_size,
220                self.max_sublist_size,
221            );
222        };
223        if owner_restrictions.is_fixed_to_current() {
224            return selected
225                .route_lens
226                .iter()
227                .map(|&route_len| {
228                    count_intra_sublist_swap_moves_for_len(
229                        route_len,
230                        self.min_sublist_size,
231                        self.max_sublist_size,
232                    )
233                })
234                .sum();
235        }
236        let owners = owner_restrictions
237            .mixed()
238            .expect("non-fixed owner restrictions retain their matrix");
239        let mut count = 0;
240        for (first_idx, &first_entity) in selected.entities.iter().enumerate() {
241            let first_len = selected.route_lens[first_idx];
242            for first_start in 0..first_len {
243                let first_max = self.max_sublist_size.min(first_len - first_start);
244                for first_size in self.min_sublist_size..=first_max {
245                    let first_end = first_start + first_size;
246                    for (second_idx, &second_entity) in
247                        selected.entities.iter().enumerate().skip(first_idx)
248                    {
249                        let second_len = selected.route_lens[second_idx];
250                        for second_start in 0..second_len {
251                            let second_max = self.max_sublist_size.min(second_len - second_start);
252                            for second_size in self.min_sublist_size..=second_max {
253                                let second_end = second_start + second_size;
254                                if first_idx == second_idx
255                                    && (second_start < first_end
256                                        || (first_start == second_start && first_end == second_end))
257                                {
258                                    continue;
259                                }
260                                let allowed = if first_entity == second_entity {
261                                    selected_segment_allows(
262                                        owners,
263                                        first_idx,
264                                        first_start,
265                                        first_end,
266                                        first_entity,
267                                    ) && selected_segment_allows(
268                                        owners,
269                                        second_idx,
270                                        second_start,
271                                        second_end,
272                                        first_entity,
273                                    )
274                                } else {
275                                    selected_segment_allows(
276                                        owners,
277                                        first_idx,
278                                        first_start,
279                                        first_end,
280                                        second_entity,
281                                    ) && selected_segment_allows(
282                                        owners,
283                                        second_idx,
284                                        second_start,
285                                        second_end,
286                                        first_entity,
287                                    )
288                                };
289                                if allowed {
290                                    count += 1;
291                                }
292                            }
293                        }
294                    }
295                }
296            }
297        }
298        count
299    }
300}
301
302fn unfiltered_sublist_swap_size(
303    route_lens: &[usize],
304    min_sublist_size: usize,
305    max_sublist_size: usize,
306) -> usize {
307    let segment_counts = route_lens
308        .iter()
309        .map(|&route_len| count_sublist_segments(route_len, min_sublist_size, max_sublist_size))
310        .collect::<Vec<_>>();
311    let intra = route_lens
312        .iter()
313        .map(|&route_len| {
314            count_intra_sublist_swap_moves_for_len(route_len, min_sublist_size, max_sublist_size)
315        })
316        .sum::<usize>();
317    let inter = (0..route_lens.len())
318        .flat_map(|left| (left + 1..route_lens.len()).map(move |right| (left, right)))
319        .map(|(left, right)| segment_counts[left] * segment_counts[right])
320        .sum::<usize>();
321    intra + inter
322}