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remove dual solver approach

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2022-01-03 14:08:01 -08:00
parent 1f964eea90
commit 8e3185ffe3
13 changed files with 44 additions and 537 deletions
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30
src/ast/rewriter/seq_axioms.cpp
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@ -1061,16 +1061,12 @@ namespace seq {
// using iterative deepening can be re-used.
//
// create recursive relation 'ra' with properties:
// ra(s, p, t, r) <- s = "" && r = ""
// ra(s, p, t, r) <- s != "" && p = "" && r = t + s
// ra(s, p, t, r) <- s != "" && p + s' = s && t + r' = r && ra(s', p, t, r')
// ra(s, p, t, r) <- s = [s0] + s' && ~prefix(p, s) && r = [s0] + r' && ra(s', p, t, r')
// ra(i, j, s, p, t, r) <- len(s) = i && len(r) = j
// ra(i, j, s, p, t, r) <- len(s) > i = 0 && p = "" && r = t + s
// ra(i, j, s, p, t, r) <- len(s) > i && p != "" && s = extract(s, 0, i) + p + extract(s, i + len(p), len(s)) && r = extract(r, 0, i) + t + extract(r, i + len(p), len(r)) && ra(i + len(p), j + len(t), s, p, t, r)
// ra(i, s, p, t, r) <- ~prefix(p, extract(s, i, len(s)) && at(s,i) = at(r,j) && ra(i + 1, j + 1, s, p, t, r)
// which amounts to:
//
// s = "" -> r = ""
// p = "" -> r = t + s
// prefix(p, s) -> p + s' = s && t + r' = r && ra(s', p, t, r')
// else -> s = [s0] + s' && r = [s0] + r' && ra(s', p, t, r')
//
// Then assert
// ra(s, p, t, replace_all(s, p, t))
@ -1085,16 +1081,23 @@ namespace seq {
sort* domain[4] = { srt, srt, srt, srt };
auto d = plugin.ensure_def(symbol("ra"), 4, domain, m.mk_bool_sort(), true);
func_decl* ra = d.get_def()->get_decl();
sort* isrt = a.mk_int();
var_ref vi(m.mk_var(5, isrt), m);
var_ref vj(m.mk_var(4, isrt), m);
var_ref vs(m.mk_var(3, srt), m);
var_ref vp(m.mk_var(2, srt), m);
var_ref vt(m.mk_var(1, srt), m);
var_ref vr(m.mk_var(0, srt), m);
var* vars[4] = { vs, vp, vt, vr };
expr_ref test1(seq.str.mk_is_empty(vs), m);
expr_ref branch1(seq.str.mk_is_empty(vr), m);
expr_ref test2(seq.str.mk_is_empty(vp), m);
var* vars[6] = { vi, vj, vs, vp, vt, vr };
expr_ref len_s(seq.str.mk_length(vs), m);
expr_ref len_r(seq.str.mk_length(vr), m);
expr_ref test1(m.mk_eq(len_s, vi), m);
expr_ref branch1(m.mk_eq(len_r, vj), m);
expr_ref test2(m.mk_and(a.mk_gt(len_s, vi), m.mk_eq(vi, a.mk_int(0)), seq.str.mk_is_empty(vp)), m);
expr_ref branch2(m.mk_eq(vr, seq.str.mk_concat(vt, vs)), m);
expr_ref test3(seq.str.mk_prefix(vp, vs), m);
NOT_IMPLEMENTED_YET();
#if 0
expr_ref test3(, m);
expr_ref s1(m_sk.mk_prefix_inv(vp, vs), m);
expr_ref r1(m_sk.mk_prefix_inv(vp, vr), m);
expr* args1[4] = { s1, vp, vt, r1 };
@ -1116,6 +1119,7 @@ namespace seq {
expr* args3[4] = { s, p, t, r };
expr_ref lit(m.mk_app(ra, 4, args3), m);
add_clause(lit);
#endif
}
void axioms::replace_re_all_axiom(expr* e) {