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Polysat: fixes in solver, forbidden intervals for eq_constraint (#5240)

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* Rename to neg_cond

* Add some logging utilities

* Implement case of forbidden interval covering the whole domain

* Implement diseq_narrow

* Do not activate constraint if we are in a conflict state

* comments

* Assert that lemma isn't undefined

* Update revert_decision to work in the case where narrowing causes propagation

* Fix case of non-disjunctive lemma from forbidden intervals

* Conflict should not leak outside user scope

* Add guard to decide(), some notes

* Add test case

* Add constraints to watchlist of unassigned variable during propagation

* Move common propagation functionality into base class

* Combine eq/diseq narrow

* Compute forbidden interval for equality constraints by considering them as p <=u 0 (or p >u 0 for disequalities)
This commit is contained in:
Jakob Rath 2021-05-03 18:30:17 +02:00 • committed by GitHub
parent 04876ba8b7
commit f7e476a4a0
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15 changed files with 350 additions and 130 deletions
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44
src/test/polysat.cpp
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@ -63,6 +63,21 @@ namespace polysat {
s.check();
}
/// Has constraints which must be inserted into other watchlist to discover UNSAT
static void test_wlist() {
scoped_solver s;
auto a = s.var(s.add_var(3));
auto b = s.var(s.add_var(3));
auto c = s.var(s.add_var(3));
auto d = s.var(s.add_var(3));
s.add_eq(d + c + b + a + 1);
s.add_eq(d + c + b + a);
s.add_eq(d + c + b);
s.add_eq(d + c);
s.add_eq(d);
s.check();
}
/**
* most basic linear equation solving.
@ -143,6 +158,23 @@ namespace polysat {
s.check();
}
/**
* unsat
* - learns 3*x + 1 == 0 by polynomial resolution
* - this forces x == 5, which means the first constraint is unsatisfiable by parity.
*/
static void test_p3() {
scoped_solver s;
auto x = s.var(s.add_var(4));
auto y = s.var(s.add_var(4));
auto z = s.var(s.add_var(4));
s.add_eq(x*x*y + 3*y + 7);
s.add_eq(2*y + z + 8);
s.add_eq(3*x + 4*y*z + 2*z*z + 1);
s.check();
}
// Unique solution: u = 5
static void test_ineq_basic1() {
scoped_solver s;
@ -376,15 +408,23 @@ namespace polysat {
void tst_polysat() {
polysat::test_add_conflicts();
polysat::test_wlist();
polysat::test_l1();
polysat::test_l2();
polysat::test_l3();
polysat::test_l4();
polysat::test_l5();
#if 0
// worry about this later
polysat::test_p1();
polysat::test_p2();
polysat::test_p3();
polysat::test_ineq_basic1();
polysat::test_ineq_basic2();
polysat::test_ineq_basic3();
polysat::test_ineq_basic4();
polysat::test_ineq_basic5();
polysat::test_ineq_basic6();
#if 0
// worry about this later
polysat::test_ineq1();
polysat::test_ineq2();
#endif