mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-08-24 03:57:51 +00:00
Code Activity

add notes and tangent lemma

Browse source 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-09-21 11:30:50 -07:00
parent 0426b23d0c
commit 444084f396
6 changed files with 49 additions and 13 deletions
Download patch file Download diff file Expand all files Collapse all files

30
src/math/polysat/ule_constraint.cpp
View file

@ -12,16 +12,17 @@ Author:
Notes:
TODO: Maybe we want to rewrite some of the following into equalities? (i.e., into p<=0)
TODO: add rewrite rules to simplify expressions
- k1 <= k2 ==> 0 <= 0 if k1 <= k2
- k1 <= k2 ==> 1 <= 0 if k1 > k2
- 0 <= p ==> 0 <= 0
- p <= -1 ==> 0 <= 0
- k*p <= 0 ==> p <= 0 if k is odd
p <= 0 <==> p = 0
-1 <= p <==> p = -1
1 <= p <==> p != 0
p <= -2 <==> p != -1
e.g.
x - 2 >= 1 <==> x != 2
2 - x >= -1 <==> x = 3
- k <= p ==> p - k <= k - 1
- p <= p + q ==> p <= -q - 1
- p + k <= p ==> p + k <= k - 1 for k > 0
--*/
@ -33,10 +34,17 @@ namespace polysat {
ule_constraint::ule_constraint(constraint_manager& m, pdd const& l, pdd const& r) :
constraint(m, ckind_t::ule_t), m_lhs(l), m_rhs(r) {
m_vars.append(l.free_vars());
for (auto v : r.free_vars())
simplify();
m_vars.append(m_lhs.free_vars());
for (auto v : m_rhs.free_vars())
if (!m_vars.contains(v))
m_vars.push_back(v);
}
void ule_constraint::simplify() {
if (m_lhs.is_val() && m_rhs.is_val()) {
if (m_lhs.val() <= m_rhs.val())
m_lhs = m_rhs = 0;