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prep for max/min diff

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This commit is contained in:
Nikolaj Bjorner 2022-05-04 02:08:11 -07:00
parent 87d2a3b4e5
commit c29cfa81ae
5 changed files with 93 additions and 2 deletions
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52
src/sat/smt/array_axioms.cpp
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@ -59,13 +59,15 @@ namespace array {
axiom_record& r = m_axiom_trail[idx];
switch (r.m_kind) {
case axiom_record::kind_t::is_store:
return assert_store_axiom(to_app(r.n->get_expr()));
return assert_store_axiom(r.n->get_app());
case axiom_record::kind_t::is_select:
return assert_select(idx, r);
case axiom_record::kind_t::is_default:
return assert_default(r);
case axiom_record::kind_t::is_extensionality:
return assert_extensionality(r.n->get_expr(), r.select->get_expr());
case axiom_record::kind_t::is_diff:
return assert_diff(r.n->get_app());
case axiom_record::kind_t::is_congruence:
return assert_congruent_axiom(r.n->get_expr(), r.select->get_expr());
default:
@ -273,6 +275,54 @@ namespace array {
return add_clause(lit1, ~lit2);
}
/**
* a = b or default(a) != default(b) or a[md(a,b)] != b[md(a,b)]
*/
bool solver::assert_diff(expr* md) {
expr* x, *y;
SASSERT(a.is_maxdiff(md, x, y) || a.is_mindiff(md, x, y));
expr* args1[2] = { x, md };
expr* args2[2] = { y, md };
literal eq = eq_internalize(x, y);
literal eq_default = eq_internalize(a.mk_default(x), a.mk_default(y));
literal eq_md = eq_internalize(a.mk_select(2, args1), a.mk_select(2, args2));
return add_clause(eq, ~eq_default, ~eq_md);
}
/**
* a = b and a[i] != c[i] => i <= md(b, c) or default(b) != default(c)
* a = c and a[i] != b[i] => i <= md(b, c) or default(b) != default(c)
* where ai = a[i], md = md(b, c)
*/
bool solver::assert_diff_select(app* ai, app* md) {
SASSERT(a.is_select(ai));
SASSERT(ai->get_num_args() == 2);
expr* A = ai->get_arg(0);
expr* i = ai->get_arg(1);
expr* B = md->get_arg(0);
expr* C = md->get_arg(1);
literal eq_default = eq_internalize(a.mk_default(B), a.mk_default(C));
arith_util autil(m);
literal ineq = mk_literal(autil.mk_le(i, md));
bool is_new = false;
if (ctx.get_enode(A)->get_root() == ctx.get_enode(B)->get_root()) {
literal eq_ab = eq_internalize(A, B);
expr* args[2] = { C, i };
literal eq_select = eq_internalize(ai, a.mk_select(2, args));
if (add_clause(~eq_ab, eq_select, ineq, ~eq_default))
is_new = true;
}
if (ctx.get_enode(A)->get_root() == ctx.get_enode(C)->get_root()) {
literal eq_ac = eq_internalize(A, C);
expr* args[2] = { B, i };
literal eq_select = eq_internalize(ai, a.mk_select(2, args));
if (add_clause(~eq_ac, eq_select, ineq, ~eq_default))
is_new = true;
}
return is_new;
}
bool solver::is_map_combinator(expr* map) const {
return a.is_map(map) || a.is_union(map) || a.is_intersect(map) || a.is_difference(map) || a.is_complement(map);
}