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Merge branch 'fix/invalid-priority-replace'
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@jcoupey
jcoupey committed Jan 29, 2025
2 parents 405ccd1 + 1564f98 commit c9deab8
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2 changes: 2 additions & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,8 @@
#### Core solving

- Solution quality regression when using lots of skills (#1193)
- Invalid route reached by `PriorityReplace` (#1162)
- Account for gain and assigned tasks to pick priority-improving moves (#1212)
- Crash due to wrong delivery values in some validity checks (#1164)
- Crash when input is valid JSON but not an object (#1172)
- Capacity array check consistency (#1086)
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198 changes: 117 additions & 81 deletions src/algorithms/local_search/local_search.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -405,14 +405,17 @@ void LocalSearch<Route,
std::vector<Eval>(_nb_vehicles,
Eval()));

// Store best priority increase for matching move. Only operators
// involving a single route and unassigned jobs can change overall
// priority (currently only UnassignedExchange).
// Store best priority increase and number of assigned tasks for use
// with operators involving a single route and unassigned jobs
// (UnassignedExchange and PriorityReplace).
std::vector<Priority> best_priorities(_nb_vehicles, 0);
std::vector<unsigned> best_removals(_nb_vehicles,
std::numeric_limits<unsigned>::max());

// Dummy init to enter first loop.
Eval best_gain(static_cast<Cost>(1));
Priority best_priority = 0;
auto best_removal = std::numeric_limits<unsigned>::max();

while (best_gain.cost > 0 || best_priority > 0) {
if (_deadline.has_value() && _deadline.value() < utils::now()) {
Expand All @@ -422,83 +425,6 @@ void LocalSearch<Route,
if (_input.has_jobs()) {
// Move(s) that don't make sense for shipment-only instances.

// PriorityReplace stuff
for (const Index u : _sol_state.unassigned) {
if (_input.jobs[u].type != JOB_TYPE::SINGLE) {
continue;
}

Priority u_priority = _input.jobs[u].priority;

for (const auto& [source, target] : s_t_pairs) {
if (source != target || !_input.vehicle_ok_with_job(source, u) ||
_sol[source].empty() ||
// We only search for net priority gains here.
(u_priority <= _sol_state.fwd_priority[source].front() &&
u_priority <= _sol_state.bwd_priority[source].back())) {
continue;
}

// Find where to stop when replacing beginning of route.
const auto fwd_over =
std::ranges::find_if(_sol_state.fwd_priority[source],
[u_priority](const auto p) {
return u_priority < p;
});
const Index fwd_over_rank =
std::distance(_sol_state.fwd_priority[source].begin(), fwd_over);
// A fwd_last_rank of zero will discard replacing the start
// of the route.
const Index fwd_last_rank =
(fwd_over_rank > 0) ? fwd_over_rank - 1 : 0;
const Priority begin_priority_gain =
u_priority - _sol_state.fwd_priority[source][fwd_last_rank];

// Find where to stop when replacing end of route.
const auto bwd_over =
std::find_if(_sol_state.bwd_priority[source].crbegin(),
_sol_state.bwd_priority[source].crend(),
[u_priority](const auto p) { return u_priority < p; });
const Index bwd_over_rank =
std::distance(_sol_state.bwd_priority[source].crbegin(), bwd_over);
const Index bwd_first_rank = _sol[source].size() - bwd_over_rank;
const Priority end_priority_gain =
u_priority - _sol_state.bwd_priority[source][bwd_first_rank];

assert(fwd_over_rank > 0 || bwd_over_rank > 0);

const auto best_current_priority =
std::max(begin_priority_gain, end_priority_gain);

if (best_current_priority > 0 &&
best_priorities[source] <= best_current_priority) {
#ifdef LOG_LS_OPERATORS
++tried_moves[OperatorName::PriorityReplace];
#endif
PriorityReplace r(_input,
_sol_state,
_sol_state.unassigned,
_sol[source],
source,
fwd_last_rank,
bwd_first_rank,
u,
best_priorities[source]);

if (r.is_valid() &&
(best_priorities[source] < r.priority_gain() ||
(best_priorities[source] == r.priority_gain() &&
best_gains[source][source] < r.gain()))) {
best_priorities[source] = r.priority_gain();
// This may potentially define a negative value as best
// gain.
best_gains[source][source] = r.gain();
best_ops[source][source] = std::make_unique<PriorityReplace>(r);
}
}
}
}

// UnassignedExchange stuff
for (const Index u : _sol_state.unassigned) {
if (_input.jobs[u].type != JOB_TYPE::SINGLE) {
Expand Down Expand Up @@ -593,6 +519,7 @@ void LocalSearch<Route,

if (better_if_valid && r.is_valid()) {
best_priorities[source] = priority_gain;
best_removals[source] = 0;
// This may potentially define a negative value as
// best gain in case priority_gain is non-zero.
best_gains[source][source] = r.gain();
Expand All @@ -604,6 +531,110 @@ void LocalSearch<Route,
}
}
}

// PriorityReplace stuff
for (const Index u : _sol_state.unassigned) {
if (_input.jobs[u].type != JOB_TYPE::SINGLE) {
continue;
}

Priority u_priority = _input.jobs[u].priority;

for (const auto& [source, target] : s_t_pairs) {
if (source != target || !_input.vehicle_ok_with_job(source, u) ||
_sol[source].empty() ||
// We only search for net priority gains here.
(u_priority <= _sol_state.fwd_priority[source].front() &&
u_priority <= _sol_state.bwd_priority[source].back())) {
continue;
}

// Find where to stop when replacing beginning of route in
// order to generate a net priority gain.
const auto fwd_over =
std::ranges::find_if(_sol_state.fwd_priority[source],
[u_priority](const auto p) {
return u_priority <= p;
});
const Index fwd_over_rank =
std::distance(_sol_state.fwd_priority[source].begin(), fwd_over);
// A fwd_last_rank of zero will discard replacing the start
// of the route.
Index fwd_last_rank = (fwd_over_rank > 0) ? fwd_over_rank - 1 : 0;
// Go back to find the biggest route beginning portion where
// splitting is possible.
while (fwd_last_rank > 0 &&
_sol[source].has_pending_delivery_after_rank(fwd_last_rank)) {
--fwd_last_rank;
}
const Priority begin_priority_gain =
u_priority - _sol_state.fwd_priority[source][fwd_last_rank];

// Find where to stop when replacing end of route in order
// to generate a net priority gain.
const auto bwd_over =
std::find_if(_sol_state.bwd_priority[source].crbegin(),
_sol_state.bwd_priority[source].crend(),
[u_priority](const auto p) {
return u_priority <= p;
});
const Index bwd_over_rank =
std::distance(_sol_state.bwd_priority[source].crbegin(), bwd_over);
Index bwd_first_rank = _sol[source].size() - bwd_over_rank;
if (bwd_first_rank == 0) {
// Sum of priorities for whole route is lower than job
// priority. We elude this case as it is covered by start
// replacing (also whole route).
assert(fwd_last_rank == _sol[source].size() - 1);
++bwd_first_rank;
}
while (
bwd_first_rank < _sol[source].size() - 1 &&
_sol[source].has_pending_delivery_after_rank(bwd_first_rank - 1)) {
++bwd_first_rank;
}
const Priority end_priority_gain =
u_priority - _sol_state.bwd_priority[source][bwd_first_rank];

assert(fwd_over_rank > 0 || bwd_over_rank > 0);

const auto best_current_priority =
std::max(begin_priority_gain, end_priority_gain);

if (best_current_priority > 0 &&
best_priorities[source] <= best_current_priority) {
#ifdef LOG_LS_OPERATORS
++tried_moves[OperatorName::PriorityReplace];
#endif
PriorityReplace r(_input,
_sol_state,
_sol_state.unassigned,
_sol[source],
source,
fwd_last_rank,
bwd_first_rank,
u,
best_priorities[source]);

if (r.is_valid()) {
const auto priority_gain = r.priority_gain();
const unsigned removal = _sol[source].size() - r.assigned();
const auto gain = r.gain();
if (std::tie(best_priorities[source],
removal,
best_gains[source][source]) <
std::tie(priority_gain, best_removals[source], gain)) {
best_priorities[source] = priority_gain;
best_removals[source] = removal;
// This may potentially define a negative value as best
// gain.
best_gains[source][source] = r.gain();
best_ops[source][source] = std::make_unique<PriorityReplace>(r);
}
}
}
}
}
}

// CrossExchange stuff
Expand Down Expand Up @@ -1808,13 +1839,16 @@ void LocalSearch<Route,
// Find best overall move, first checking priority increase then
// best gain if no priority increase is available.
best_priority = 0;
best_removal = std::numeric_limits<unsigned>::max();
best_gain = Eval();
Index best_source = 0;
Index best_target = 0;

for (unsigned s_v = 0; s_v < _nb_vehicles; ++s_v) {
if (best_priorities[s_v] > best_priority) {
if (std::tie(best_priority, best_removals[s_v], best_gain) <
std::tie(best_priorities[s_v], best_removal, best_gains[s_v][s_v])) {
best_priority = best_priorities[s_v];
best_removal = best_removals[s_v];
best_gain = best_gains[s_v][s_v];
best_source = s_v;
best_target = s_v;
Expand Down Expand Up @@ -1916,6 +1950,7 @@ void LocalSearch<Route,
for (auto v_rank : update_candidates) {
best_gains[v_rank].assign(_nb_vehicles, Eval());
best_priorities[v_rank] = 0;
best_removals[v_rank] = std::numeric_limits<unsigned>::max();
best_ops[v_rank] = std::vector<std::unique_ptr<Operator>>(_nb_vehicles);
}

Expand Down Expand Up @@ -1958,6 +1993,7 @@ void LocalSearch<Route,
if (invalidate_move) {
best_gains[v][v] = Eval();
best_priorities[v] = 0;
best_removals[v] = std::numeric_limits<unsigned>::max();
best_ops[v][v] = std::unique_ptr<Operator>();
s_t_pairs.emplace_back(v, v);
}
Expand Down
18 changes: 16 additions & 2 deletions src/problems/cvrp/operators/priority_replace.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -35,10 +35,13 @@ PriorityReplace::PriorityReplace(const Input& input,
_sol_state.fwd_priority[s_vehicle][s_rank]),
_end_priority_gain(_input.jobs[u].priority -
_sol_state.bwd_priority[s_vehicle][t_rank]),
_start_assigned_number(s_route.size() - s_rank),
_end_assigned_number(t_rank + 1),
_u(u),
_best_known_priority_gain(best_known_priority_gain),
_unassigned(unassigned) {
assert(!s_route.empty());
assert(t_rank != 0);
assert(_start_priority_gain > 0 or _end_priority_gain > 0);
}

Expand Down Expand Up @@ -111,8 +114,8 @@ void PriorityReplace::compute_gain() {

if (replace_start_valid && replace_end_valid) {
// Decide based on priority and cost.
if (std::tie(_end_priority_gain, t_gain) <
std::tie(_start_priority_gain, s_gain)) {
if (std::tie(_end_priority_gain, _end_assigned_number, t_gain) <
std::tie(_start_priority_gain, _start_assigned_number, s_gain)) {
replace_end_valid = false;
} else {
replace_start_valid = false;
Expand Down Expand Up @@ -144,6 +147,8 @@ bool PriorityReplace::is_valid() {
j.delivery,
0,
s_rank + 1);
assert(!replace_start_valid ||
!source.has_pending_delivery_after_rank(s_rank));

// Don't bother if the candidate end portion is empty or with a
// single job (that would be an UnassignedExchange move).
Expand All @@ -156,6 +161,8 @@ bool PriorityReplace::is_valid() {
j.delivery,
t_rank,
s_route.size());
assert(!replace_end_valid ||
!source.has_pending_delivery_after_rank(t_rank - 1));

// Check validity with regard to vehicle range bounds, requires
// valid gain values for both options.
Expand Down Expand Up @@ -216,6 +223,13 @@ Priority PriorityReplace::priority_gain() {
return replace_start_valid ? _start_priority_gain : _end_priority_gain;
}

unsigned PriorityReplace::assigned() const {
assert(gain_computed);
assert(replace_start_valid xor replace_end_valid);

return replace_start_valid ? _start_assigned_number : _end_assigned_number;
}

std::vector<Index> PriorityReplace::addition_candidates() const {
return {s_vehicle};
}
Expand Down
4 changes: 4 additions & 0 deletions src/problems/cvrp/operators/priority_replace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,8 @@ class PriorityReplace : public ls::Operator {
bool _end_gain_computed{false};
const Priority _start_priority_gain;
const Priority _end_priority_gain;
const unsigned _start_assigned_number;
const unsigned _end_assigned_number;

protected:
const Index _u; // Unassigned job to insert.
Expand Down Expand Up @@ -55,6 +57,8 @@ class PriorityReplace : public ls::Operator {

Priority priority_gain();

unsigned assigned() const;

std::vector<Index> addition_candidates() const override;

std::vector<Index> update_candidates() const override;
Expand Down

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