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add option to "rotate" cores during core finding

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enable to find multiple cores in a round and at the same time facilitate rotation around satisfiable subsets to explore neighborhoods for improved assignments.
This commit is contained in:
Nikolaj Bjorner 2022-05-01 20:58:11 +02:00
parent 5a9b0dd747
commit b5c7f000de
6 changed files with 510 additions and 25 deletions
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53
src/opt/maxcore.cpp
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@ -11,8 +11,8 @@ Abstract:
- mu: max-sat algorithm by Nina and Bacchus, AAAI 2014.
- mus-mss: based on dual refinement of bounds.
- binary
- binary-delay
- binary: binary versino of maxres
- rc2: implementaion of rc2 heuristic using cardinality constraints
MaxRes is a core-guided approach to maxsat.
@ -66,6 +66,7 @@ Notes:
#include "opt/opt_context.h"
#include "opt/opt_params.hpp"
#include "opt/opt_lns.h"
#include "opt/opt_cores.h"
#include "opt/maxsmt.h"
#include "opt/maxcore.h"
@ -119,7 +120,6 @@ private:
bool m_hill_climb; // prefer large weight soft clauses for cores
unsigned m_last_index; // last index used during hill-climbing
bool m_add_upper_bound_block; // restrict upper bound with constraint
unsigned m_max_num_cores; // max number of cores per round.
unsigned m_max_core_size; // max core size per round.
bool m_maximize_assignment; // maximize assignment to find MCS
unsigned m_max_correction_set_size;// maximal set of correction set that is tolerated.
@ -127,9 +127,9 @@ private:
// this option is disabled if SAT core is used.
bool m_pivot_on_cs; // prefer smaller correction set to core.
bool m_dump_benchmarks; // display benchmarks (into wcnf format)
bool m_enable_lns { false }; // enable LNS improvements
unsigned m_lns_conflicts { 1000 }; // number of conflicts used for LNS improvement
bool m_enable_lns = false; // enable LNS improvements
unsigned m_lns_conflicts = 1000; // number of conflicts used for LNS improvement
bool m_enable_core_rotate = false;
std::string m_trace_id;
typedef ptr_vector<expr> exprs;
@ -148,7 +148,6 @@ public:
m_correction_set_size(0),
m_found_feasible_optimum(false),
m_hill_climb(true),
m_last_index(0),
m_add_upper_bound_block(false),
m_max_num_cores(UINT_MAX),
m_max_core_size(3),
@ -323,17 +322,15 @@ public:
Give preference to cores that have large minimal values.
*/
sort_assumptions(asms);
m_last_index = 0;
unsigned last_index = 0;
unsigned index = 0;
bool first = index > 0;
SASSERT(index < asms.size() || asms.empty());
IF_VERBOSE(10, verbose_stream() << "start hill climb " << index << " asms: " << asms.size() << "\n";);
while (index < asms.size() && is_sat == l_true) {
while (!first && asms.size() > 20*(index - m_last_index) && index < asms.size()) {
while (asms.size() > 20*(index - last_index) && index < asms.size()) {
index = next_index(asms, index);
}
first = false;
m_last_index = index;
last_index = index;
is_sat = check_sat(index, asms.data());
}
}
@ -390,13 +387,6 @@ public:
st.update("maxsat-correction-sets", m_stats.m_num_cs);
}
struct weighted_core {
exprs m_core;
rational m_weight;
weighted_core(exprs const& c, rational const& w):
m_core(c), m_weight(w) {}
};
lbool get_cores(vector<weighted_core>& cores) {
// assume m_s is unsat.
lbool is_sat = l_false;
@ -434,8 +424,8 @@ public:
remove_soft(core, m_asms);
split_core(core);
if (core.size() >= m_max_core_size) break;
if (cores.size() >= m_max_num_cores) break;
if (core.size() >= m_max_core_size)
break;
is_sat = check_sat_hill_climb(m_asms);
}
@ -511,6 +501,9 @@ public:
}
lbool process_unsat() {
if (m_enable_core_rotate)
return core_rotate();
vector<weighted_core> cores;
lbool is_sat = get_cores(cores);
if (is_sat != l_true) {
@ -525,6 +518,21 @@ public:
}
}
lbool core_rotate() {
cores find_cores(s(), m_lnsctx);
find_cores.updt_params(m_params);
vector<weighted_core> const& cores = find_cores();
for (auto const & [core, w] : cores) {
if (core.empty())
return l_false;
remove_soft(core, m_asms);
split_core(core);
process_unsat(core, w);
}
return l_true;
}
unsigned max_core_size(vector<exprs> const& cores) {
unsigned result = 0;
for (auto const& c : cores) {
@ -980,7 +988,6 @@ public:
opt_params p(_p);
m_hill_climb = p.maxres_hill_climb();
m_add_upper_bound_block = p.maxres_add_upper_bound_block();
m_max_num_cores = p.maxres_max_num_cores();
m_max_core_size = p.maxres_max_core_size();
m_maximize_assignment = p.maxres_maximize_assignment();
m_max_correction_set_size = p.maxres_max_correction_set_size();
@ -988,6 +995,7 @@ public:
m_wmax = p.maxres_wmax();
m_dump_benchmarks = p.dump_benchmarks();
m_enable_lns = p.enable_lns();
m_enable_core_rotate = p.enable_core_rotate();
m_lns_conflicts = p.lns_conflicts();
if (m_c.num_objectives() > 1)
m_add_upper_bound_block = false;
@ -1000,7 +1008,6 @@ public:
add_soft(e, w);
m_max_upper = m_upper;
m_found_feasible_optimum = false;
m_last_index = 0;
add_upper_bound_block();
m_csmodel = nullptr;
m_correction_set_size = 0;