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Complete euf project with eq and diseq on pure representatives

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This commit is contained in:
Arie Gurfinkel 2018-06-12 17:23:46 -07:00
parent b246389267
commit 535b8893ae
3 changed files with 65 additions and 27 deletions
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43
src/qe/qe_mbi.cpp
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@ -33,18 +33,18 @@ Notes:
Sketch of approach by example:
A: s <= 2a <= t & f(a) = q
B: t <= 2b <= s + 1 & f(b) != q
1. Extract arithmetic consequences of A over shared vocabulary.
A -> s <= t & (even(t) | s < t)
A -> s <= t & (even(t) | s < t)
2a. Send to B, have B solve shared variables with EUF_B.
epsilon b . B & A_pure
epsilon b . t <= 2b <= s + 1 & s <= t & (even(t) | s < t)
= t <= s + 1 & (even(t) | t <= s) & s <= t & (even(t) | s < t)
= even(t) & t = s
epsilon b . t <= 2b <= s + 1 & s <= t & (even(t) | s < t)
= t <= s + 1 & (even(t) | t <= s) & s <= t & (even(t) | s < t)
= even(t) & t = s
b := t div 2
B & A_pure -> B[b/t div 2] = f(t div 2) != q & t <= s + 1
@ -53,13 +53,13 @@ Notes:
A & B_pure -> false
Invoke the ping-pong principle to extract interpolant.
2b. Solve for shared variables with EUF.
epsilon a . A
epsilon a . A
= a := (s + 1) div 2 & s < t & f((s + 1) div 2) = q
3b. Send to B. Produces core
3b. Send to B. Produces core
s < t & f((s + 1) div 2) = q
4b Solve again in arithmetic for shared variables with EUF.
@ -71,7 +71,7 @@ Notes:
Send to B, produces core (s != t | f(t div 2) != q)
5b. There is no longer a solution for A. A is unsat.
--*/
#include "ast/ast_util.h"
@ -138,7 +138,7 @@ namespace qe {
void prop_mbi_plugin::block(expr_ref_vector const& lits) {
m_solver->assert_expr(mk_not(mk_and(lits)));
}
}
// -------------------------------
// euf_mbi, TBD
@ -158,8 +158,8 @@ namespace qe {
void operator()(expr*) {}
};
euf_mbi_plugin::euf_mbi_plugin(solver* s, solver* sNot):
m(s->get_manager()),
euf_mbi_plugin::euf_mbi_plugin(solver* s, solver* sNot):
m(s->get_manager()),
m_atoms(m),
m_solver(s),
m_dual_solver(sNot) {
@ -205,11 +205,11 @@ namespace qe {
// use the dual solver to find a 'small' implicant
m_dual_solver->get_unsat_core(core);
TRACE("qe", tout << "core: " << core << "\n";);
// project the implicant onto vars
// project the implicant onto vars
tg.set_vars(vars, false);
tg.add_lits(core);
lits.reset();
lits.append(tg.project());
lits.reset();
lits.append(tg.project(*mdl));
TRACE("qe", tout << "project: " << lits << "\n";);
return mbi_sat;
case l_undef:
@ -232,8 +232,8 @@ namespace qe {
void euf_mbi_plugin::block(expr_ref_vector const& lits) {
m_solver->assert_expr(mk_not(mk_and(lits)));
}
}
/** --------------------------------------------------------------
* ping-pong interpolation of Gurfinkel & Vizel
@ -255,7 +255,7 @@ namespace qe {
auto* t2 = turn ? &b : &a;
mbi_result next_res = (*t1)(vars, lits, mdl);
switch (next_res) {
case mbi_sat:
case mbi_sat:
if (last_res == mbi_sat) {
itp = nullptr;
return l_true;
@ -264,7 +264,7 @@ namespace qe {
break; // continue
case mbi_unsat: {
if (lits.empty()) {
// TBD, either a => itp and itp => !b
// TBD, either a => itp and itp => !b
// or b => itp and itp => !a
itp = mk_and(itps[!turn]);
return l_false;
@ -282,7 +282,7 @@ namespace qe {
case mbi_augment:
break;
case mbi_undef:
return l_undef;
return l_undef;
}
turn = !turn;
last_res = next_res;
@ -319,4 +319,3 @@ namespace qe {
}
}
};