mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-22 16:45:31 +00:00
Code Activity

fi disequal: add special treatment for v > -a*v

Browse source
This commit is contained in:
Jakob Rath 2022-01-24 17:03:49 +01:00
parent 7d3308b00e
commit 8c2f268506
2 changed files with 48 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

27
src/math/polysat/viable.cpp
View file

@ -327,10 +327,31 @@ namespace polysat {
};
if (lhs > rhs || (e->src.is_negative() && lhs == rhs)) {
rational lo = val - delta_l(val);
rational hi = val + delta_u(val) + 1;
rational lo;
rational hi;
// TODO: extract into separate function
if (e->src.is_negative() && a2.is_one() && b1.is_zero() && b2.is_zero()) {
// special case: v > -a*v for some numeral a
rational const& a = mod(-a1, mod_value);
if (val.is_zero()) {
lo = 0;
hi = ceil( (mod_value + 1) / (a + 1) );
} else {
rational const y = mod(-a * val, mod_value);
lo = ceil( val + (y - max_value) / a );
hi = ceil( (y + a*val + 1) / (a + 1) );
// can always extend to 0
if (lo.is_one())
lo = 0;
}
} else {
// general case
lo = val - delta_l(val);
hi = val + delta_u(val) + 1;
// TODO: increase interval
}
// TODO: increase interval
LOG("refine-disequal-lin: " << " [" << lo << ", " << hi << "[");
SASSERT(0 <= lo && lo <= val);

24
src/test/polysat.cpp
View file

@ -1097,6 +1097,29 @@ public:
s.check();
}
static void test_fi_disequal_mild() {
{
// small version
scoped_solver s(__func__);
auto a = s.var(s.add_var(6));
auto b = s.var(s.add_var(6));
// v > -3*v
s.add_eq(a - 3);
s.add_ult(-a*b, b);
s.check();
}
{
// large version
scoped_solver s(__func__);
auto a = s.var(s.add_var(256));
auto b = s.var(s.add_var(256));
// v > -100*v
s.add_eq(a - 100);
s.add_ult(-a*b, b);
s.check();
}
}
// Goal: we probably mix up polysat variables and PDD variables at several points; try to uncover such cases
// NOTE: actually, add_var seems to keep them in sync, so this is not an issue at the moment (but we should still test it later)
// static void test_mixed_vars() {
@ -1352,6 +1375,7 @@ void tst_polysat() {
test_polysat::test_fi_zero();
test_polysat::test_fi_nonzero();
test_polysat::test_fi_nonmax();
test_polysat::test_fi_disequal_mild();
return;
test_polysat::test_l2();