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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-11-08 05:08:57 -08:00
parent e1bc9cc0bb
commit 57c40e480b
8 changed files with 120 additions and 96 deletions
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65
src/math/polysat/saturation.cpp
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@ -70,11 +70,17 @@ namespace polysat {
SASSERT(!crit1.is_currently_true(s));
LOG("critical " << m_rule << " " << crit1);
LOG("consequent " << c << " value: " << c.bvalue(s));
LOG("consequent " << c << " value: " << c.bvalue(s) << " " << c.is_currently_false(s) << " " << core.contains(~c));
// ensure new core is a conflict
if (!c.is_currently_false(s) && c.bvalue(s) != l_false)
return false;
// avoid loops
if (core.contains(~c))
return false;
core.reset();
for (auto d : m_new_constraints)
core.insert(d);
@ -272,12 +278,12 @@ namespace polysat {
* [x] zx > yx ==> Ω*(x,y) \/ z > y
* [x] yx <= zx ==> Ω*(x,y) \/ y <= z \/ x = 0
*/
bool inf_saturate::try_ugt_x(pvar v, conflict& core, inequality const& c) {
bool inf_saturate::try_ugt_x(pvar v, conflict& core, inequality const& xy_l_xz) {
set_rule("zx <= yx");
pdd x = s.var(v);
pdd y = x;
pdd z = x;
if (!is_xY_l_xZ(v, c, y, z))
if (!is_xY_l_xZ(v, xy_l_xz, y, z))
return false;
if (!is_non_overflow(x, y))
return false;
@ -288,40 +294,37 @@ namespace polysat {
if (!c.is_strict)
m_new_constraints.push_back(~s.eq(x));
push_omega(x, y);
return propagate(core, c, c, c.is_strict, y, z);
return propagate(core, xy_l_xz, xy_l_xz, xy_l_xz.is_strict, y, z);
}
/// [y] z' <= y /\ zx > yx ==> Ω*(x,y) \/ zx > z'x
/// [y] z' <= y /\ yx <= zx ==> Ω*(x,y) \/ z'x <= zx
bool inf_saturate::try_ugt_y(pvar v, conflict& core, inequality const& le_y, inequality const& yx_l_zx, pdd const& x, pdd const& z) {
pdd const y = s.var(v);
SASSERT(is_l_v(v, le_y));
SASSERT(verify_Xy_l_XZ(v, yx_l_zx, x, z));
pdd const y = s.var(v);
if (!is_non_overflow(x, y))
return false;
return false;
pdd const& z_prime = le_y.lhs;
m_new_constraints.reset();
push_omega(x, y);
// z'x <= zx
return propagate(core, le_y, yx_l_zx, yx_l_zx.is_strict || le_y.is_strict, z_prime * x, z * x);
}
bool inf_saturate::try_ugt_y(pvar v, conflict& core, inequality const& c) {
set_rule("z' <= y & yx <= zx");
if (!is_l_v(v, c))
return false;
bool inf_saturate::try_ugt_y(pvar v, conflict& core, inequality const& yx_l_zx) {
set_rule("[y] z' <= y & yx <= zx");
pdd x = s.var(v);
pdd z = x;
if (!is_Xy_l_XZ(v, yx_l_zx, x, z))
return false;
for (auto si : s.m_search) {
if (!si.is_boolean())
continue;
auto dd = s.lit2cnstr(si.lit());
if (!dd->is_ule())
continue;
auto d = dd.as_inequality();
if (is_Xy_l_XZ(v, d, x, z) && try_ugt_y(v, core, c, d, x, z))
auto le_y = dd.as_inequality();
if (is_l_v(v, le_y) && try_ugt_y(v, core, le_y, yx_l_zx, x, z))
return true;
}
return false;
@ -330,30 +333,26 @@ namespace polysat {
/// [x] y <= ax /\ x <= z (non-overflow case)
/// ==> Ω*(a, z) \/ y <= az
bool inf_saturate::try_y_l_ax_and_x_l_z(pvar x, conflict& core, inequality const& c) {
set_rule("y <= ax & x <= z");
bool inf_saturate::try_y_l_ax_and_x_l_z(pvar x, conflict& core, inequality const& y_l_ax) {
set_rule("[x] y <= ax & x <= z");
pdd y = s.var(x);
pdd a = y;
if (!is_Y_l_Ax(x, c, a, y))
if (!is_Y_l_Ax(x, y_l_ax, a, y))
return false;
for (auto si : s.m_search) {
if (!si.is_boolean())
continue;
auto dd = s.lit2cnstr(si.lit());
if (!dd->is_ule())
continue;
if (dd.is_currently_true(s))
continue;
auto d = dd.as_inequality();
if (is_g_v(x, d) && try_y_l_ax_and_x_l_z(x, core, c, d, a, y))
auto x_l_z = dd.as_inequality();
if (is_g_v(x, x_l_z) && try_y_l_ax_and_x_l_z(x, core, y_l_ax, x_l_z, a, y))
return true;
}
return false;
}
bool inf_saturate::try_y_l_ax_and_x_l_z(pvar x, conflict& core, inequality const& y_l_ax, inequality const& x_l_z, pdd const& a, pdd const& y) {
SASSERT(is_g_v(x, x_l_z));
SASSERT(verify_Y_l_Ax(x, y_l_ax, a, y));
pdd z = x_l_z.rhs;
@ -361,28 +360,26 @@ namespace polysat {
return false;
m_new_constraints.reset();
push_omega(a, z);
return propagate(core, x_l_z, y_l_ax, x_l_z.is_strict || y_l_ax.is_strict, y, a * z);
return propagate(core, y_l_ax, x_l_z, x_l_z.is_strict || y_l_ax.is_strict, y, a * z);
}
/// [z] z <= y' /\ zx > yx ==> Ω*(x,y') \/ y'x > yx
/// [z] z <= y' /\ yx <= zx ==> Ω*(x,y') \/ yx <= y'x
bool inf_saturate::try_ugt_z(pvar z, conflict& core, inequality const& c) {
set_rule("ugt_z");
if (!is_g_v(z, c))
return false;
bool inf_saturate::try_ugt_z(pvar z, conflict& core, inequality const& yx_l_zx) {
set_rule("[z] z <= y' /\ zx > yx");
pdd y = s.var(z);
pdd x = y;
if (!is_YX_l_zX(z, yx_l_zx, x, y))
return false;
for (auto si : s.m_search) {
if (!si.is_boolean())
continue;
auto dd = s.lit2cnstr(si.lit());
if (!dd->is_ule())
continue;
if (!dd.is_currently_false(s))
continue;
auto d = dd.as_inequality();
if (is_YX_l_zX(z, d, x, y) && try_ugt_z(z, core, c, d, x, y))
auto z_l_y = dd.as_inequality();
if (is_g_v(z, z_l_y) && try_ugt_z(z, core, z_l_y, yx_l_zx, x, y))
return true;
}
return false;
@ -408,7 +405,7 @@ namespace polysat {
// ==> value(p) <= p => value(p) < q
bool inf_saturate::try_tangent(pvar v, conflict& core, inequality const& c) {
set_rule("tangent");
set_rule("[x] p(x) <= q(x) where value(p) > value(q)");
if (c.is_strict)
return false;
if (!c.src->contains_var(v))