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testing bounds strengthening code

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-08-06 17:05:54 -07:00
parent 481e20bc20
commit f47930a4ff
5 changed files with 295 additions and 93 deletions

View file

@ -252,12 +252,12 @@ namespace polysat {
void fixed_var_eh(row const& r, var_t x);
void eq_eh(var_t x, var_t y, row const& r1, row const& r2);
lbool propagate_bounds(row const& r);
lbool propagate_bounds(ineq const& i);
lbool new_bound(row const& r, var_t x, mod_interval<numeral> const& range);
lbool new_bound(ineq const& i, var_t x, numeral const& lo, numeral const& hi, u_dependency* a = nullptr, u_dependency* b = nullptr);
lbool conflict(ineq const& i, u_dependency* a = nullptr, u_dependency* b = nullptr);
lbool conflict(u_dependency* a);
lbool conflict(u_dependency* a, u_dependency* b) { return conflict(m_deps.mk_join(a, b)); }
bool propagate_bounds(ineq const& i);
bool new_bound(row const& r, var_t x, mod_interval<numeral> const& range);
bool new_bound(ineq const& i, var_t x, numeral const& lo, numeral const& hi, u_dependency* a = nullptr, u_dependency* b = nullptr, u_dependency* c = nullptr, u_dependency* d = nullptr);
void conflict(ineq const& i, u_dependency* a = nullptr, u_dependency* b = nullptr, u_dependency* c = nullptr, u_dependency* d = nullptr);
void conflict(u_dependency* a);
void conflict(u_dependency* a, u_dependency* b, u_dependency* c = nullptr, u_dependency* d = nullptr) { conflict(m_deps.mk_join(m_deps.mk_join(a, b), m_deps.mk_join(c, d))); }
u_dependency* row2dep(row const& r);
void pivot(var_t x_i, var_t x_j, numeral const& b, numeral const& value);
numeral value2delta(var_t v, numeral const& new_value) const;
@ -297,7 +297,9 @@ namespace polysat {
// facilities for handling inequalities
void add_ineq(var_t v, var_t w, unsigned dep, bool strict);
void touch_var(var_t x);
lbool check_ineqs();
bool ineqs_are_violated();
bool ineqs_are_satisfied();
void reset_ineqs_to_check();
bool is_solved(row const& r) const;
bool is_solved(var_t v) const { SASSERT(is_base(v)); return is_solved(base2row(v)); }

View file

@ -149,13 +149,17 @@ namespace polysat {
return l_false;
case l_undef:
m_to_patch.insert(v);
if (l_false == check_ineqs())
if (ineqs_are_violated())
return l_false;
return l_undef;
}
}
SASSERT(well_formed());
return check_ineqs();
if (ineqs_are_violated())
return l_false;
if (ineqs_are_satisfied())
return l_true;
return l_undef;
}
template<typename Ext>
@ -352,7 +356,6 @@ namespace polysat {
return l_undef;
}
pivot(x, y, b, new_value);
return l_true;
@ -499,8 +502,7 @@ namespace polysat {
}
template<typename Ext>
typename fixplex<Ext>::numeral
fixplex<Ext>::value2error(var_t v, numeral const& value) const {
typename fixplex<Ext>::numeral fixplex<Ext>::value2error(var_t v, numeral const& value) const {
if (in_bounds(v))
return 0;
SASSERT(lo(v) != hi(v));
@ -519,6 +521,7 @@ namespace polysat {
*/
template<typename Ext>
void fixplex<Ext>::set_bounds(var_t v, numeral const& l, numeral const& h, unsigned dep) {
ensure_var(v);
update_bounds(v, l, h, mk_leaf(dep));
if (in_bounds(v))
return;
@ -571,6 +574,8 @@ namespace polysat {
template<typename Ext>
void fixplex<Ext>::add_ineq(var_t v, var_t w, unsigned dep, bool strict) {
ensure_var(v);
ensure_var(w);
unsigned idx = m_ineqs.size();
m_var2ineqs.reserve(std::max(v, w) + 1);
m_var2ineqs[v].push_back(idx);
@ -604,31 +609,51 @@ namespace polysat {
}
template<typename Ext>
lbool fixplex<Ext>::check_ineqs() {
m_vars_to_untouch.reset();
void fixplex<Ext>::reset_ineqs_to_check() {
for (auto idx : m_ineqs_to_check) {
if (idx >= m_ineqs.size())
continue;
auto& ineq = m_ineqs[idx];
m_var_is_touched.setx(ineq.v, false, false);
m_var_is_touched.setx(ineq.w, false, false);
ineq.is_active = false;
}
m_ineqs_to_check.reset();
}
/**
* Check if the current assignment satisfies the inequalities
*/
template<typename Ext>
bool fixplex<Ext>::ineqs_are_satisfied() {
for (auto idx : m_ineqs_to_check) {
if (idx >= m_ineqs.size())
continue;
auto& ineq = m_ineqs[idx];
var_t v = ineq.v;
var_t w = ineq.w;
if (ineq.strict && value(v) >= value(w)) {
IF_VERBOSE(0, verbose_stream() << "violated v" << v << " < v" << w << "\n");
return l_false;
}
if (!ineq.strict && value(v) > value(w)) {
IF_VERBOSE(0, verbose_stream() << "violated v" << v << " <= v" << w << "\n");
return l_false;
}
ineq.is_active = false;
m_vars_to_untouch.push_back(v);
m_vars_to_untouch.push_back(w);
if (ineq.strict && value(v) >= value(w))
return false;
if (!ineq.strict && value(v) > value(w))
return false;
}
for (auto v : m_vars_to_untouch)
m_var_is_touched.set(v, false);
m_ineqs_to_check.reset();
m_vars_to_untouch.reset();
return l_true;
reset_ineqs_to_check();
return true;
}
/**
* Propagate bounds and check if the current inequalities are satisfied
*/
template<typename Ext>
bool fixplex<Ext>::ineqs_are_violated() {
for (unsigned i = 0; i < m_ineqs_to_check.size(); ++i) {
unsigned idx = m_ineqs_to_check[i];
if (idx >= m_ineqs.size())
continue;
if (!propagate_bounds(m_ineqs[idx]))
return true;
}
return false;
}
@ -1087,16 +1112,16 @@ namespace polysat {
m_var_eqs.push_back(var_eq(x, y, r1, r2));
}
template<typename Ext>
lbool fixplex<Ext>::propagate_bounds() {
lbool r = l_true;
for (unsigned i = 0; r == l_true && i < m_rows.size(); ++i)
r = propagate_bounds(row(i));
if (r != l_true)
return r;
for (auto ineq : m_ineqs) {
if (r != l_true)
break;
r = propagate_bounds(ineq);
if (!propagate_bounds(ineq))
return l_false;
}
return r;
}
@ -1132,7 +1157,7 @@ namespace polysat {
if (free_v != null_var) {
range = (-range) * free_c;
lbool res = new_bound(r, free_v, range);
lbool res = new_bound(r, free_v, range) ? l_true : l_false;
SASSERT(in_bounds(free_v));
return res;
}
@ -1140,7 +1165,7 @@ namespace polysat {
var_t v = e.var();
SASSERT(!is_free(v));
auto range1 = range - m_vars[v] * e.coeff();
lbool res = new_bound(r, v, range1);
lbool res = new_bound(r, v, range1) ? l_true : l_false;
if (res != l_true)
return res;
// SASSERT(in_bounds(v));
@ -1149,56 +1174,61 @@ namespace polysat {
}
template<typename Ext>
lbool fixplex<Ext>::propagate_bounds(ineq const& i) {
bool fixplex<Ext>::propagate_bounds(ineq const& i) {
// v < w & lo(v) + 1 = 0 -> conflict
// v < w & hi(w) = 0 -> conflict
// v < w & lo(v) >= hi(w) -> conflict
// v <= w & lo(v) > hi(w) -> conflict
// v < w & hi(v) >= hi(w) -> hi(v) := hi(w) - 1
// v < w & lo(v) >= lo(w) -> lo(w) := lo(v) + 1
// v < w & lo(w) = 0 & hi(w) = 1 -> conflict
// v < w & hi(w) != 0 & lo(w) <= hi(w) & hi(w) - 1 <= lo(v) -> conflict
// v <= w & hi(w) != 0 & lo(w) <= hi(w) & hi(w) <= lo(v) -> conflict
// v < w & hi(w) != 0 & lo(w) <= hi(w) <= hi(v) -> hi(v) := hi(w) - 1
// v < w & lo(w) <= lo(v) -> lo(w) := lo(v) + 1
// v <= w & hi(v) > hi(w) -> hi(v) := hi(w)
// v <= w & lo(v) > lo(w) -> lo(w) := lo(w)
var_t v = i.v, w = i.w;
bool s = i.strict;
if (s && lo(v) + 1 == 0)
return conflict(i, m_vars[v].m_lo_dep);
else if (s && hi(w) == 0)
return conflict(i, m_vars[v].m_hi_dep);
else if (s && lo(v) >= hi(w))
return conflict(i, m_vars[v].m_lo_dep, m_vars[w].m_hi_dep);
else if (!s && lo(v) > hi(w))
return conflict(i, m_vars[v].m_lo_dep, m_vars[w].m_hi_dep);
else if (s && hi(v) >= hi(w)) {
SASSERT(lo(v) < hi(w));
SASSERT(hi(w) != 0);
return new_bound(i, v, lo(v), hi(w) - 1, m_vars[v].m_hi_dep, m_vars[w].m_hi_dep);
}
else if (s && lo(v) >= lo(w)) {
SASSERT(lo(v) + 1 != 0);
SASSERT(hi(w) > lo(v));
return new_bound(i, w, lo(v) + 1, hi(w), m_vars[v].m_lo_dep, m_vars[w].m_lo_dep);
}
else if (!s && hi(v) > hi(w)) {
SASSERT(lo(v) <= hi(w));
return new_bound(i, v, lo(v), hi(w), m_vars[v].m_hi_dep, m_vars[w].m_hi_dep);
}
else if (!s && lo(v) > lo(w)) {
SASSERT(lo(v) <= hi(w));
return new_bound(i, w, lo(v), hi(w), m_vars[v].m_lo_dep, m_vars[w].m_lo_dep);
}
return l_true;
auto* vlo = m_vars[v].m_lo_dep, *vhi = m_vars[v].m_hi_dep;
auto* wlo = m_vars[w].m_lo_dep, *whi = m_vars[w].m_hi_dep;
if (s && lo(v) + 1 == 0 && is_fixed(v))
return conflict(i, vlo, vhi), false;
if (s && lo(w) == 0 && is_fixed(w))
return conflict(i, wlo, whi), false;
if (s && hi(w) != 0 && lo(w) <= hi(w) && lo(v) <= hi(v) && hi(w) - 1 <= lo(v))
return conflict(i, vlo, wlo, whi), false;
if (s && hi(v) == 0 && lo(w) < hi(w) && hi(w) - 1 <= lo(v))
return conflict(i, vlo, vhi, wlo, whi), false;
if (!s && hi(w) != 0 && lo(w) <= hi(w) && hi(w) <= lo(v) && lo(v) <= hi(v))
return conflict(i, vlo, vhi, wlo, whi), false;
if (!s && hi(w) != 0 && lo(w) <= hi(w) && hi(w) <= lo(v) && hi(v) == 0)
return conflict(i, vlo, vhi, wlo, whi), false;
if (s && hi(w) != 0 && lo(w) <= hi(w) && hi(w) <= hi(v) && !new_bound(i, v, lo(v), hi(w) - 1, wlo, vhi, whi))
return false;
if (s && lo(w) <= lo(v) && !new_bound(i, w, lo(v) + 1, hi(w), vlo, wlo))
return false;
if (s && hi(w) != 0 && hi(w) - 1 <= lo(v) && lo(v) <= hi(v) && hi(w) < lo(w) && !new_bound(i, w, lo(w), 0, wlo, whi, vlo, vhi))
return false;
if (s && hi(w) == 1 && !is_fixed(w) && !new_bound(i, w, lo(w), 0, wlo, whi))
return false;
if (!s && hi(v) > hi(w) && !new_bound(i, v, lo(v), hi(w), vhi, whi))
return false;
if (!s && lo(v) > lo(w) && !new_bound(i, w, lo(v), hi(w), vlo, wlo))
return false;
if (!s && hi(w) != 0 && hi(w) < lo(w) && hi(w) <= lo(v) && lo(v) <= hi(v) && !new_bound(i, w, lo(w), 0, vlo, vhi, wlo, whi))
return false;
if (hi(w) != 0 && lo(w) <= hi(w) && hi(w) <= lo(v) && !new_bound(i, v, 0, hi(v), wlo, vlo, whi))
return false;
return true;
}
template<typename Ext>
lbool fixplex<Ext>::conflict(ineq const& i, u_dependency* a, u_dependency* b) {
return conflict(a, m_deps.mk_join(mk_leaf(i.dep), b));
void fixplex<Ext>::conflict(ineq const& i, u_dependency* a, u_dependency* b, u_dependency* c, u_dependency* d) {
conflict(a, m_deps.mk_join(mk_leaf(i.dep), m_deps.mk_join(b, m_deps.mk_join(c, d))));
}
template<typename Ext>
lbool fixplex<Ext>::conflict(u_dependency* a) {
void fixplex<Ext>::conflict(u_dependency* a) {
m_unsat_core.reset();
m_deps.linearize(a, m_unsat_core);
return l_false;
TRACE("polysat", tout << "core: " << m_unsat_core << "\n";);
}
template<typename Ext>
@ -1213,31 +1243,31 @@ namespace polysat {
}
template<typename Ext>
lbool fixplex<Ext>::new_bound(ineq const& i, var_t x, numeral const& l, numeral const& h, u_dependency* a, u_dependency* b) {
bool fixplex<Ext>::new_bound(ineq const& i, var_t x, numeral const& l, numeral const& h, u_dependency* a, u_dependency* b, u_dependency* c, u_dependency* d) {
bool was_fixed = lo(x) + 1 == hi(x);
u_dependency* dep = m_deps.mk_join(mk_leaf(i.dep), m_deps.mk_join(a, b));
u_dependency* dep = m_deps.mk_join(mk_leaf(i.dep), m_deps.mk_join(a, m_deps.mk_join(b, m_deps.mk_join(c, d))));
update_bounds(x, l, h, dep);
if (m_vars[x].is_empty())
return conflict(m_vars[x].m_lo_dep, m_vars[x].m_hi_dep);
return conflict(m_vars[x].m_lo_dep, m_vars[x].m_hi_dep), false;
else if (!was_fixed && lo(x) + 1 == hi(x)) {
// TBD: track based on inequality not row
// fixed_var_eh(r, x);
}
return l_true;
return true;
}
template<typename Ext>
lbool fixplex<Ext>::new_bound(row const& r, var_t x, mod_interval<numeral> const& range) {
bool fixplex<Ext>::new_bound(row const& r, var_t x, mod_interval<numeral> const& range) {
if (range.is_free())
return l_true;
bool was_fixed = lo(x) + 1 == hi(x);
update_bounds(x, range.lo, range.hi, row2dep(r));
IF_VERBOSE(0, verbose_stream() << "new-bound v" << x << " " << m_vars[x] << "\n");
if (m_vars[x].is_empty())
return conflict(m_vars[x].m_lo_dep, m_vars[x].m_hi_dep);
if (m_vars[x].is_empty())
return conflict(m_vars[x].m_lo_dep, m_vars[x].m_hi_dep), false;
else if (!was_fixed && lo(x) + 1 == hi(x))
fixed_var_eh(r, x);
return l_true;
return true;
}
template<typename Ext>
@ -1249,6 +1279,12 @@ namespace polysat {
if (vi.m_is_base) out << "b:" << vi.m_base2row << " " << pp(m_rows[vi.m_base2row].m_value) << " ";
out << "\n";
}
for (auto const& i : m_ineqs) {
if (i.strict)
out << "v" << i.v << " < v" << i.w << "\n";
else
out << "v" << i.v << " <= v" << i.w << "\n";
}
return out;
}

View file

@ -286,12 +286,10 @@ namespace polysat {
lbool linear_solver::check() {
lbool res = l_true;
m_unsat_f = nullptr;
for (auto* f : m_fix) {
if (!f)
continue;
lbool r = f->make_feasible();
for (auto* fp : m_fix_ptr) {
lbool r = fp->make_feasible();
if (r == l_false) {
m_unsat_f = f;
m_unsat_f = fp;
return r;
}
if (r == l_undef)
@ -313,12 +311,13 @@ namespace polysat {
}
// current value assigned to (linear) variable according to tableau.
rational linear_solver::value(pvar v) {
bool linear_solver::value(pvar v, rational& val) {
unsigned sz = s.size(v);
auto* fp = sz2fixplex(sz);
if (!fp)
return rational::zero();
return fp->get_value(pvar2var(sz, v));
return false;
val = fp->get_value(pvar2var(sz, v));
return true;
}
};

View file

@ -41,8 +41,6 @@ namespace polysat {
inc_level_i,
add_var_i,
add_mono_i,
add_ineq_i,
add_row_i,
set_active_i
};
@ -135,7 +133,7 @@ namespace polysat {
void unsat_core(ptr_vector<constraint>& constraints, unsigned_vector& deps);
// current value assigned to (linear) variable according to tableau.
rational value(pvar v);
bool value(pvar v, rational& val);
std::ostream& display(std::ostream& out) const { return out; }
void collect_statistics(::statistics & st) const {}

View file

@ -1,5 +1,10 @@
#include "math/polysat/fixplex.h"
#include "math/polysat/fixplex_def.h"
#include "ast/bv_decl_plugin.h"
#include "ast/reg_decl_plugins.h"
#include "smt/smt_kernel.h"
#include "smt/params/smt_params.h"
namespace polysat {
@ -118,7 +123,6 @@ namespace polysat {
static void test_gcd() {
std::cout << "gcd\n";
uint64_ext::manager e;
uint64_t x = 0, y = 0, z = 0, a = 0, b = 0;
uint64_t g = e.gcd(15, 27);
std::cout << g << "\n";
std::cout << 15 << " " << e.mul_inverse(15) << " " << 15*e.mul_inverse(15) << "\n";
@ -126,9 +130,172 @@ namespace polysat {
std::cout << 60 << " " << e.mul_inverse(60) << " " << 60*e.mul_inverse(60) << "\n";
std::cout << 29 << " " << e.mul_inverse(29) << " " << 29*e.mul_inverse(29) << "\n";
}
static void test_ineq1() {
std::cout << "ineq1\n";
scoped_fp fp;
var_t x = 0, y = 1;
fp.add_lt(x, y, 1);
fp.add_le(y, x, 2);
fp.run();
}
static void test_ineqs() {
var_t x = 0, y = 1;
unsigned nb = 6;
uint64_t bounds[6] = { 0, 1, 2, 10 , (uint64_t)-2, (uint64_t)-1 };
ast_manager m;
reg_decl_plugins(m);
bv_util bv(m);
expr_ref X(m.mk_const("x", bv.mk_sort(64)), m);
expr_ref Y(m.mk_const("y", bv.mk_sort(64)), m);
smt_params pa;
smt::kernel solver(m, pa);
auto mk_ult = [&](expr* a, expr* b) {
return m.mk_not(bv.mk_ule(b, a));
};
auto add_bound = [&](expr* x, uint64_t i, uint64_t j) {
expr_ref I(bv.mk_numeral(i, 64), m);
expr_ref J(bv.mk_numeral(j, 64), m);
if (i < j) {
solver.assert_expr(bv.mk_ule(I, x));
solver.assert_expr(mk_ult(x, J));
}
else if (i > j && j != 0)
solver.assert_expr(m.mk_or(bv.mk_ule(I, x), mk_ult(x, J)));
else if (i > j && j == 0)
solver.assert_expr(bv.mk_ule(I, x));
};
auto test_le = [&](bool test_le, uint64_t i, uint64_t j, uint64_t k, uint64_t l) {
if (i == j && i != 0)
return;
if (k == l && k != 0)
return;
scoped_fp fp;
fp.set_bounds(x, i, j, 1);
fp.set_bounds(y, k, l, 2);
if (test_le)
fp.add_le(x, y, 3);
else
fp.add_lt(x, y, 3);
lbool feas = fp.make_feasible();
// validate result
solver.push();
if (test_le)
solver.assert_expr(bv.mk_ule(X, Y));
else
solver.assert_expr(mk_ult(X, Y));
add_bound(X, i, j);
add_bound(Y, k, l);
lbool feas2 = solver.check();
if (feas == feas2) {
solver.pop(1);
return;
}
if (feas2 == l_false && feas == l_true) {
std::cout << "BUG!\n";
solver.pop(1);
return;
}
bool bad = false;
switch (feas) {
case l_false:
for (unsigned c : fp.get_unsat_core())
std::cout << c << "\n";
std::cout << "\n";
break;
case l_true:
case l_undef:
// Check for missed bounds:
solver.push();
solver.assert_expr(m.mk_eq(X, bv.mk_numeral(fp.lo(x), 64)));
if (l_true != solver.check()) {
std::cout << "missed lower bound on x\n";
bad = true;
}
solver.pop(1);
solver.push();
solver.assert_expr(m.mk_eq(Y, bv.mk_numeral(fp.lo(y), 64)));
if (l_true != solver.check()) {
std::cout << "missed lower bound on y\n";
bad = true;
}
solver.pop(1);
if (fp.lo(x) != fp.hi(x) && fp.hi(x) != 0) {
solver.push();
solver.assert_expr(m.mk_eq(X, bv.mk_numeral(fp.hi(x)-1, 64)));
if (l_true != solver.check()) {
std::cout << "missed upper bound on x\n";
bad = true;
}
solver.pop(1);
}
if (fp.lo(y) != fp.hi(y) && fp.hi(y) != 0) {
solver.push();
solver.assert_expr(m.mk_eq(Y, bv.mk_numeral(fp.hi(y) - 1, 64)));
if (l_true != solver.check()) {
std::cout << "missed upper bound on y\n";
bad = true;
}
solver.pop(1);
}
if (bad) {
std::cout << fp << "\n";
std::cout << feas << " " << feas2 << "\n";
}
break;
}
// check assignment is valid when returning satisfiable.
if (false && feas == l_true) {
rational vx = fp.get_value(x);
rational vy = fp.get_value(y);
SASSERT(vx <= vy);
SASSERT(i >= j || (rational(i, rational::ui64()) <= vx && vx < rational(j, rational::ui64())));
SASSERT(k >= l || (rational(k, rational::ui64()) <= vy && vy < rational(l, rational::ui64())));
}
solver.pop(1);
return;
};
for (unsigned i = 0; i < nb; ++i)
for (unsigned j = 0; j < nb; ++j)
for (unsigned k = 0; k < nb; ++k)
for (unsigned l = 0; l < nb; ++l) {
test_le(true, bounds[i], bounds[j], bounds[k], bounds[l]);
test_le(false, bounds[i], bounds[j], bounds[k], bounds[l]);
}
}
}
void tst_fixplex() {
polysat::test_ineq1();
polysat::test_ineqs();
return;
polysat::test1();
polysat::test2();
polysat::test3();