mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-24 17:45:32 +00:00
Code Activity

add TODO marker in saturation for overflow rule

Browse source 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2022-12-03 09:07:24 -08:00
parent 0657cdd4a7
commit 0288704a59
2 changed files with 77 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

66
src/math/polysat/saturation.cpp
View file

@ -128,6 +128,31 @@ namespace polysat {
return i.lhs() == y && i.rhs() == a * s.var(x);
}
/**
* Match [x] a*x <= y
*/
bool saturation::is_Ax_l_Y(pvar x, inequality const& i, pdd& a, pdd& y) {
y = i.rhs();
return is_xY(x, i.lhs(), a);
}
bool saturation::verify_Ax_l_Y(pvar x, inequality const& i, pdd const& a, pdd const& y) {
return i.rhs() == y && i.lhs() == a * s.var(x);
}
/**
* Match [x] a*x + b <= y
*/
bool saturation::is_AxB_l_Y(pvar x, inequality const& i, pdd& a, pdd& b, pdd& y) {
y = i.rhs();
pdd aa = a, bb = b;
return i.lhs().degree(x) == 1 && (i.lhs().factor(x, 1, aa, bb), aa == a && bb == b);
}
bool saturation::verify_AxB_l_Y(pvar x, inequality const& i, pdd const& a, pdd const& b, pdd const& y) {
return i.rhs() == y && i.lhs() == a * s.var(x) + b;
}
/**
* Match [coeff*x] coeff*x*Y where x is a variable
*/
@ -339,6 +364,47 @@ namespace polysat {
* x*y = k & ~ovfl(x,y) & x = j => y = k/j where j is a divisor of k
*/
bool saturation::try_mul_bounds(pvar x, conflict& core, inequality const& axb_l_y) {
set_rule("[x] ax + b <= y & y = 0 & b = 0 & a <= k => x = 0 or a = 0 or x >= 2^K/k");
auto& m = s.var2pdd(x);
pdd y = m.zero();
pdd a = m.zero();
pdd b = m.zero();
pdd k = m.zero();
rational b_val, y_val;
if (!is_AxB_l_Y(x, axb_l_y, a, b, y))
return false;
if (a.is_one())
return false;
if (!s.try_eval(b, b_val))
return false;
if (b_val != 0)
return false;
if (!s.try_eval(y, y_val))
return false;
if (y_val != 0)
return false;
for (auto si : s.m_search) {
if (!si.is_boolean())
continue;
if (si.is_resolved())
continue;
auto d = s.lit2cnstr(si.lit());
if (!d->is_ule())
continue;
auto a_l_k = inequality::from_ule(d);
if (a_l_k.lhs() != a)
continue;
if (!k.is_val())
continue;
if (k.val() == 0)
continue;
// propagate(core, axb_l_y, a_l_k, b = 0, y = 0 => x = 0 or a = 0 or x >= 2^K/k)
}
return false;
}
/**
* [x] p(x) <= q(x) where value(p) > value(q)
* ==> q <= value(q) => p <= value(q)

13
src/math/polysat/saturation.h
View file

@ -44,6 +44,7 @@ namespace polysat {
bool try_ugt_z(pvar z, conflict& core, inequality const& c);
bool try_ugt_z(pvar z, conflict& core, inequality const& x_l_z0, inequality const& yz_l_xz, pdd const& y, pdd const& x);
bool try_mul_bounds(pvar x, conflict& core, inequality const& axb_l_y);
bool try_tangent(pvar v, conflict& core, inequality const& c);
// c := lhs ~ v
@ -61,8 +62,16 @@ namespace polysat {
bool verify_Xy_l_XZ(pvar y, inequality const& c, pdd const& x, pdd const& z);
// c := Y ~ Ax
bool is_Y_l_Ax(pvar x, inequality const& d, pdd& a, pdd& y);
bool verify_Y_l_Ax(pvar x, inequality const& d, pdd const& a, pdd const& y);
bool is_Y_l_Ax(pvar x, inequality const& c, pdd& a, pdd& y);
bool verify_Y_l_Ax(pvar x, inequality const& c, pdd const& a, pdd const& y);
// c := Ax ~ Y
bool is_Ax_l_Y(pvar x, inequality const& c, pdd& a, pdd& y);
bool verify_Ax_l_Y(pvar x, inequality const& c, pdd const& a, pdd const& y);
// c := Ax + B ~ Y
bool is_AxB_l_Y(pvar x, inequality const& c, pdd& a, pdd& b, pdd& y);
bool verify_AxB_l_Y(pvar x, inequality const& c, pdd const& a, pdd const& b, pdd const& y);
// c := Y*X ~ z*X
bool is_YX_l_zX(pvar z, inequality const& c, pdd& x, pdd& y);