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cleanup

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Nikolaj Bjorner 2023-12-31 15:22:21 -08:00
parent 57cb999061
commit b25451bd87
3 changed files with 31 additions and 35 deletions
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29
src/sat/smt/polysat/saturation.cpp
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@ -10,18 +10,6 @@ Author:
Nikolaj Bjorner (nbjorner) 2021-03-19
Jakob Rath 2021-04-6
TODO: preserve falsification
- each rule selects a certain premises that are problematic.
If the problematic premise is false under the current assignment, the newly inferred
literal should also be false in the assignment in order to preserve conflicts.
TODO: when we check that 'x' is "unary":
- in principle, 'x' could be any polynomial. However, we need to divide the lhs by x, and we don't have general polynomial division yet.
so for now we just allow the form 'value*variable'.
(extension to arbitrary monomials for 'x' should be fairly easy too)
--*/
#include "sat/smt/polysat/core.h"
#include "sat/smt/polysat/saturation.h"
@ -125,16 +113,15 @@ namespace polysat {
pdd x = c.var(v);
pdd y = x;
pdd z = x;
auto& C = c.cs();
if (!i.is_xY_l_xZ(v, y, z))
return;
auto ovfl = C.umul_ovfl(x, y);
if (i.is_strict())
add_clause("[x] yx < zx ==> Ω*(x,y) \\/ y < z", { i.dep(), ovfl, C.ult(y, z)}, false);
add_clause("[x] yx < zx ==> Ω*(x,y) \\/ y < z", { i.dep(), ovfl, C.ult(y, z)}, true);
else
add_clause("[x] yx <= zx ==> Ω*(x,y) \\/ y <= z \\/ x = 0", { i.dep(), ovfl, C.eq(x), C.ule(y, z) }, false);
add_clause("[x] yx <= zx ==> Ω*(x,y) \\/ y <= z \\/ x = 0", { i.dep(), ovfl, C.eq(x), C.ule(y, z) }, true);
}
/**
@ -149,14 +136,14 @@ namespace polysat {
auto y = c.var(v);
pdd x = y;
pdd z = y;
auto& C = c.cs();
if (!i.is_Xy_l_XZ(v, x, z))
return;
for (constraint_id id : constraint_iterator(c, [&](auto const& sc) { return inequality::is_l_v(y, sc); })) {
auto j = inequality::from_ule(c, id);
pdd const& z_prime = i.lhs();
bool is_strict = i.is_strict() || j.is_strict();
add_clause("[y] z' <= y & yx <= zx", { i.dep(), j.dep(), C.umul_ovfl(x, y), ineq(is_strict, z_prime * x, z * x) }, true);
add_clause("[y] z' <= y & yx <= zx ==> Ω*(x,y) \/ z'x <= zx",
{ i.dep(), j.dep(), C.umul_ovfl(x, y), ineq(is_strict, z_prime * x, z * x) }, true);
}
}
@ -178,14 +165,14 @@ namespace polysat {
auto j = inequality::from_ule(c, id);
auto y_prime = j.rhs();
bool is_strict = i.is_strict() || j.is_strict();
add_clause("[z] z <= y' && yx <= zx", { i.dep(), j.dep(), c.umul_ovfl(x, y_prime), ineq(is_strict, y * x, y_prime * x) }, true);
add_clause("[z] z <= y' && yx <= zx ==> Ω*(x,y') \/ yx <= y'x",
{ i.dep(), j.dep(), c.umul_ovfl(x, y_prime), ineq(is_strict, y * x, y_prime * x) }, true);
}
}
// Ovfl(x, y) & ~Ovfl(y, z) ==> x > z
void saturation::try_umul_ovfl(pvar v, umul_ovfl const& sc) {
auto p = sc.p(), q = sc.q();
auto& C = c.cs();
auto match_mul_arg = [&](auto const& sc2) {
auto p2 = sc2.to_umul_ovfl().p(), q2 = sc2.to_umul_ovfl().q();
return p == p2 || p == q2 || q == p2 || q == q2;
@ -209,9 +196,9 @@ namespace polysat {
auto d2 = c.get_dependency(id);
auto [q1, q2] = extract_mul_args(sc2);
if (sc.sign())
add_clause("[y] ~ovfl(p, q1) & ovfl(p, q2) ==> q1 < q2", { d1, d2, C.ult(q1, q2) }, false);
add_clause("[y] ~ovfl(p, q1) & ovfl(p, q2) ==> q1 < q2", { d1, d2, C.ult(q1, q2) }, true);
else
add_clause("[y] ovfl(p, q1) & ~ovfl(p, q2) ==> q1 > q2", { d1, d2, C.ult(q2, q1)}, false);
add_clause("[y] ovfl(p, q1) & ~ovfl(p, q2) ==> q1 > q2", { d1, d2, C.ult(q2, q1)}, true);
}
}