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wip - adding context equation solver

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the solve_eqs_tactic is to be replaced by a re-implementation that uses solve_eqs in the simplifiers directory.
The re-implementation should address efficiency issues with the previous code.
At this point it punts on low level proofs. The plan is to use coarser
dependency tracking instead of low level proofs for pre-processing. Dependencies can be converted into a proof hint representation that can be checked using a stronger checker.
This commit is contained in:
Nikolaj Bjorner 2022-11-05 10:34:57 -07:00
parent ae2672f132
commit 4d8860c0bc
15 changed files with 416 additions and 117 deletions
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39
src/ast/simplifiers/solve_eqs.cpp
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@ -23,22 +23,29 @@ Author:
#include "ast/recfun_decl_plugin.h"
#include "ast/rewriter/expr_replacer.h"
#include "ast/simplifiers/solve_eqs.h"
#include "ast/simplifiers/solve_context_eqs.h"
#include "ast/converters/generic_model_converter.h"
#include "params/tactic_params.hpp"
namespace euf {
void solve_eqs::get_eqs(dep_eq_vector& eqs) {
for (extract_eq* ex : m_extract_plugins)
for (unsigned i = m_qhead; i < m_fmls.size(); ++i)
ex->get_eqs(m_fmls[i], eqs);
}
// initialize graph that maps variable ids to next ids
void solve_eqs::extract_dep_graph(dep_eq_vector& eqs) {
m_var2id.reset();
m_id2var.reset();
m_next.reset();
unsigned sz = 0;
for (auto const& [v, t, d] : eqs)
for (auto const& [orig, v, t, d] : eqs)
sz = std::max(sz, v->get_id());
m_var2id.resize(sz + 1, UINT_MAX);
for (auto const& [v, t, d] : eqs) {
for (auto const& [orig, v, t, d] : eqs) {
if (is_var(v) || !can_be_var(v))
continue;
m_var2id[v->get_id()] = m_id2var.size();
@ -91,7 +98,7 @@ namespace euf {
continue;
m_id2level[id] = curr_level++;
for (auto const& eq : m_next[j]) {
auto const& [v, t, d] = eq;
auto const& [orig, v, t, d] = eq;
if (!is_safe(curr_level, t))
continue;
m_next[j][0] = eq;
@ -114,7 +121,7 @@ namespace euf {
for (unsigned id : m_subst_ids) {
if (!m.inc())
break;
auto const& [v, def, dep] = m_next[id][0];
auto const& [orig, v, def, dep] = m_next[id][0];
auto [new_def, new_dep] = rp->replace_with_dep(def);
m_stats.m_num_steps += rp->get_num_steps() + 1;
++m_stats.m_num_elim_vars;
@ -134,7 +141,7 @@ namespace euf {
});
}
void solve_eqs::apply_subst() {
void solve_eqs::apply_subst(vector<dependent_expr>& old_fmls) {
if (!m.inc())
return;
scoped_ptr<expr_replacer> rp = mk_default_expr_replacer(m, true);
@ -146,6 +153,7 @@ namespace euf {
if (new_f == f)
continue;
new_dep = m.mk_join(d, new_dep);
old_fmls.push_back(m_fmls[i]);
m_fmls.update(i, dependent_expr(m, new_f, new_dep));
}
}
@ -157,6 +165,7 @@ namespace euf {
unsigned count = 0;
do {
vector<dependent_expr> old_fmls;
m_subst_ids.reset();
if (!m.inc())
return;
@ -164,18 +173,30 @@ namespace euf {
get_eqs(eqs);
extract_dep_graph(eqs);
extract_subst();
apply_subst();
apply_subst(old_fmls);
++count;
}
while (!m_subst_ids.empty() && count < 20);
save_subst({});
if (m_config.m_context_solve) {
vector<dependent_expr> old_fmls;
dep_eq_vector eqs;
m_subst_ids.reset();
solve_context_eqs context_solve(*this);
context_solve.collect_nested_equalities(eqs);
extract_dep_graph(eqs);
extract_subst();
apply_subst(old_fmls);
save_subst(old_fmls);
}
advance_qhead(m_fmls.size());
save_subst();
}
void solve_eqs::save_subst() {
void solve_eqs::save_subst(vector<dependent_expr> const& old_fmls) {
if (!m_subst->empty())
m_fmls.model_trail()->push(m_subst.detach(), {});
m_fmls.model_trail().push(m_subst.detach(), old_fmls);
}
void solve_eqs::filter_unsafe_vars() {