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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-01-05 21:51:34 -08:00
parent 2acab46388
commit 63fc62fbe4
6 changed files with 72 additions and 51 deletions
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30
src/sat/sat_anf_simplifier.cpp
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@ -15,8 +15,10 @@
--*/
#include "util/union_find.h"
#include "sat/sat_anf_simplifier.h"
#include "sat/sat_solver.h"
#include "sat/sat_elim_eqs.h"
#include "sat/sat_xor_finder.h"
#include "sat/sat_aig_finder.h"
#include "math/grobner/pdd_solver.h"
@ -32,7 +34,7 @@ namespace sat {
IF_VERBOSE(2,
verbose_stream() << " (sat.anf.simplifier"
<< " :num-units " << s.m_stats.m_num_units
<< " :num-eqs " << s.m_stats.m_num_eq
<< " :num-eqs " << s.m_stats.m_num_eqs
<< " :mb " << mem_stat()
<< m_watch << ")\n");
}
@ -61,6 +63,15 @@ namespace sat {
*/
void anf_simplifier::anf2clauses(pdd_solver& solver) {
union_find_default_ctx ctx;
union_find<> uf(ctx);
for (unsigned i = 2*s.num_vars(); i--> 0; ) uf.mk_var();
auto add_eq = [&](literal l1, literal l2) {
uf.merge(l1.index(), l2.index());
uf.merge((~l1).index(), (~l2).index());
};
unsigned old_num_eqs = m_stats.m_num_eqs;
for (auto* e : solver.equations()) {
auto const& p = e->poly();
if (p.is_one()) {
@ -80,13 +91,17 @@ namespace sat {
// x + y + c = 0
SASSERT(!p.is_val() && p.hi().is_one() && !p.lo().is_val() && p.lo().hi().is_one() && p.lo().lo().is_val());
literal x(p.var(), false);
literal y(p.lo().var(), p.lo().lo().is_zero());
s.mk_clause(x, y, true);
s.mk_clause(~x, ~y, true);
++m_stats.m_num_eq;
literal y(p.lo().var(), p.lo().lo().is_one());
add_eq(x, y);
++m_stats.m_num_eqs;
TRACE("anf_simplifier", tout << "equivalence " << p << " : " << x << " == " << y << "\n";);
}
}
if (old_num_eqs < m_stats.m_num_eqs) {
elim_eqs elim(s);
elim(uf);
}
}
/**
@ -104,13 +119,13 @@ namespace sat {
void anf_simplifier::anf2phase(pdd_solver& solver) {
if (!m_config.m_anf2phase)
return;
m_eval_ts = 0;
reset_eval();
auto const& eqs = solver.equations();
for (unsigned i = eqs.size(); i-- > 0; ) {
dd::pdd const& p = eqs[i]->poly();
if (!p.is_val() && p.hi().is_one() && s.m_best_phase[p.var()] != eval(p.lo())) {
s.m_best_phase[p.var()] = !s.m_best_phase[p.var()];
++m_stats.m_num_phase_flips;
}
}
}
@ -415,10 +430,11 @@ namespace sat {
void anf_simplifier::save_statistics(pdd_solver& solver) {
solver.collect_statistics(m_st);
m_st.update("sat-anf.units", m_stats.m_num_units);
m_st.update("sat-anf.eqs", m_stats.m_num_eq);
m_st.update("sat-anf.eqs", m_stats.m_num_eqs);
m_st.update("sat-anf.ands", m_stats.m_num_aigs);
m_st.update("sat-anf.ites", m_stats.m_num_ifs);
m_st.update("sat-anf.xors", m_stats.m_num_xors);
m_st.update("sat-anf.phase_flips", m_stats.m_num_phase_flips);
}
}