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reorganizing the code

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
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Leonardo de Moura 2012-10-23 22:14:35 -07:00
parent 9e299b88c4
commit 0a4446ae26
255 changed files with 17 additions and 17 deletions
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src/rewriter/der.cpp
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@ -1,467 +0,0 @@
/*++
Copyright (c) 2006 Microsoft Corporation
Module Name:
der.cpp
Abstract:
<abstract>
Author:
Leonardo de Moura (leonardo) 2008-01-27.
Revision History:
Christoph Wintersteiger, 2010-03-30: Added Destr. Multi-Equality Resolution
--*/
#include"der.h"
#include"occurs.h"
#include"for_each_expr.h"
#include"rewriter_def.h"
#include"ast_pp.h"
#include"ast_ll_pp.h"
#include"ast_smt2_pp.h"
static bool is_var(expr * e, unsigned num_decls) {
return is_var(e) && to_var(e)->get_idx() < num_decls;
}
static bool is_neg_var(ast_manager & m, expr * e, unsigned num_decls) {
return m.is_not(e) && is_var(to_app(e)->get_arg(0)) && to_var(to_app(e)->get_arg(0))->get_idx() < num_decls;
}
/**
\brief Return true if \c e is of the form (not (= VAR t)) or (not (iff VAR t)) or (iff VAR t) or (iff (not VAR) t) or (VAR IDX) or (not (VAR IDX)).
The last case can be viewed
*/
bool der::is_var_diseq(expr * e, unsigned num_decls, var * & v, expr_ref & t) {
// (not (= VAR t)) and (not (iff VAR t)) cases
if (m_manager.is_not(e) && (m_manager.is_eq(to_app(e)->get_arg(0)) || m_manager.is_iff(to_app(e)->get_arg(0)))) {
app * eq = to_app(to_app(e)->get_arg(0));
SASSERT(m_manager.is_eq(eq) || m_manager.is_iff(eq));
expr * lhs = eq->get_arg(0);
expr * rhs = eq->get_arg(1);
if (!is_var(lhs, num_decls) && !is_var(rhs, num_decls))
return false;
if (!is_var(lhs, num_decls))
std::swap(lhs, rhs);
SASSERT(is_var(lhs, num_decls));
// Remark: Occurs check is not necessary here... the top-sort procedure will check for cycles...
// if (occurs(lhs, rhs)) {
// return false;
// }
v = to_var(lhs);
t = rhs;
TRACE("der", tout << mk_pp(e, m_manager) << "\n";);
return true;
}
// (iff VAR t) and (iff (not VAR) t) cases
else if (m_manager.is_iff(e)) {
expr * lhs = to_app(e)->get_arg(0);
expr * rhs = to_app(e)->get_arg(1);
// (iff VAR t) case
if (is_var(lhs, num_decls) || is_var(rhs, num_decls)) {
if (!is_var(lhs, num_decls))
std::swap(lhs, rhs);
SASSERT(is_var(lhs, num_decls));
// Remark: Occurs check is not necessary here... the top-sort procedure will check for cycles...
// if (occurs(lhs, rhs)) {
// return false;
// }
v = to_var(lhs);
t = m_manager.mk_not(rhs);
m_new_exprs.push_back(t);
TRACE("der", tout << mk_pp(e, m_manager) << "\n";);
return true;
}
// (iff (not VAR) t) case
else if (is_neg_var(m_manager, lhs, num_decls) || is_neg_var(m_manager, rhs, num_decls)) {
if (!is_neg_var(m_manager, lhs, num_decls))
std::swap(lhs, rhs);
SASSERT(is_neg_var(m_manager, lhs, num_decls));
expr * lhs_var = to_app(lhs)->get_arg(0);
// Remark: Occurs check is not necessary here... the top-sort procedure will check for cycles...
// if (occurs(lhs_var, rhs)) {
// return false;
// }
v = to_var(lhs_var);
t = rhs;
TRACE("der", tout << mk_pp(e, m_manager) << "\n";);
return true;
}
else {
return false;
}
}
// VAR != false case
else if (is_var(e, num_decls)) {
t = m_manager.mk_false();
v = to_var(e);
TRACE("der", tout << mk_pp(e, m_manager) << "\n";);
return true;
}
// VAR != true case
else if (is_neg_var(m_manager, e, num_decls)) {
t = m_manager.mk_true();
v = to_var(to_app(e)->get_arg(0));
TRACE("der", tout << mk_pp(e, m_manager) << "\n";);
return true;
}
else {
return false;
}
}
void der::operator()(quantifier * q, expr_ref & r, proof_ref & pr) {
bool reduced = false;
pr = 0;
r = q;
TRACE("der", tout << mk_pp(q, m_manager) << "\n";);
// Keep applying it until r doesn't change anymore
do {
proof_ref curr_pr(m_manager);
q = to_quantifier(r);
reduce1(q, r, curr_pr);
if (q != r)
reduced = true;
if (m_manager.proofs_enabled()) {
pr = m_manager.mk_transitivity(pr, curr_pr);
}
} while (q != r && is_quantifier(r));
// Eliminate variables that have become unused
if (reduced && is_forall(r)) {
quantifier * q = to_quantifier(r);
elim_unused_vars(m_manager, q, r);
if (m_manager.proofs_enabled()) {
proof * p1 = m_manager.mk_elim_unused_vars(q, r);
pr = m_manager.mk_transitivity(pr, p1);
}
}
m_new_exprs.reset();
}
void der::reduce1(quantifier * q, expr_ref & r, proof_ref & pr) {
if (!is_forall(q)) {
pr = 0;
r = q;
return;
}
expr * e = q->get_expr();
unsigned num_decls = q->get_num_decls();
var * v = 0;
expr_ref t(m_manager);
if (m_manager.is_or(e)) {
unsigned num_args = to_app(e)->get_num_args();
unsigned i = 0;
unsigned diseq_count = 0;
unsigned largest_vinx = 0;
m_map.reset();
m_pos2var.reset();
m_inx2var.reset();
m_pos2var.reserve(num_args, -1);
// Find all disequalities
for (; i < num_args; i++) {
if (is_var_diseq(to_app(e)->get_arg(i), num_decls, v, t)) {
unsigned idx = v->get_idx();
if(m_map.get(idx, 0) == 0) {
m_map.reserve(idx + 1, 0);
m_inx2var.reserve(idx + 1, 0);
m_map[idx] = t;
m_inx2var[idx] = v;
m_pos2var[i] = idx;
diseq_count++;
largest_vinx = (idx>largest_vinx) ? idx : largest_vinx;
}
}
}
if (diseq_count > 0) {
get_elimination_order();
SASSERT(m_order.size() <= diseq_count); // some might be missing because of cycles
if (!m_order.empty()) {
create_substitution(largest_vinx + 1);
apply_substitution(q, r);
}
}
else {
TRACE("der_bug", tout << "Did not find any diseq\n" << mk_pp(q, m_manager) << "\n";);
r = q;
}
}
// Remark: get_elimination_order/top-sort checks for cycles, but it is not invoked for unit clauses.
// So, we must perform a occurs check here.
else if (is_var_diseq(e, num_decls, v, t) && !occurs(v, t)) {
r = m_manager.mk_false();
}
else
r = q;
if (m_manager.proofs_enabled()) {
pr = r == q ? 0 : m_manager.mk_der(q, r);
}
}
void der_sort_vars(ptr_vector<var> & vars, ptr_vector<expr> & definitions, unsigned_vector & order) {
order.reset();
// eliminate self loops, and definitions containing quantifiers.
bool found = false;
for (unsigned i = 0; i < definitions.size(); i++) {
var * v = vars[i];
expr * t = definitions[i];
if (t == 0 || has_quantifiers(t) || occurs(v, t))
definitions[i] = 0;
else
found = true; // found at least one candidate
}
if (!found)
return;
typedef std::pair<expr *, unsigned> frame;
svector<frame> todo;
expr_fast_mark1 visiting;
expr_fast_mark2 done;
unsigned vidx, num;
for (unsigned i = 0; i < definitions.size(); i++) {
if (definitions[i] == 0)
continue;
var * v = vars[i];
SASSERT(v->get_idx() == i);
SASSERT(todo.empty());
todo.push_back(frame(v, 0));
while (!todo.empty()) {
start:
frame & fr = todo.back();
expr * t = fr.first;
if (t->get_ref_count() > 1 && done.is_marked(t)) {
todo.pop_back();
continue;
}
switch (t->get_kind()) {
case AST_VAR:
vidx = to_var(t)->get_idx();
if (fr.second == 0) {
CTRACE("der_bug", vidx >= definitions.size(), tout << "vidx: " << vidx << "\n";);
// Remark: The size of definitions may be smaller than the number of variables occuring in the quantified formula.
if (definitions.get(vidx, 0) != 0) {
if (visiting.is_marked(t)) {
// cycle detected: remove t
visiting.reset_mark(t);
definitions[vidx] = 0;
}
else {
visiting.mark(t);
fr.second = 1;
todo.push_back(frame(definitions[vidx], 0));
goto start;
}
}
}
else {
SASSERT(fr.second == 1);
if (definitions.get(vidx, 0) != 0) {
visiting.reset_mark(t);
order.push_back(vidx);
}
else {
// var was removed from the list of candidate vars to elim cycle
// do nothing
}
}
if (t->get_ref_count() > 1)
done.mark(t);
todo.pop_back();
break;
case AST_QUANTIFIER:
UNREACHABLE();
todo.pop_back();
break;
case AST_APP:
num = to_app(t)->get_num_args();
while (fr.second < num) {
expr * arg = to_app(t)->get_arg(fr.second);
fr.second++;
if (arg->get_ref_count() > 1 && done.is_marked(arg))
continue;
todo.push_back(frame(arg, 0));
goto start;
}
if (t->get_ref_count() > 1)
done.mark(t);
todo.pop_back();
break;
default:
UNREACHABLE();
todo.pop_back();
break;
}
}
}
}
void der::get_elimination_order() {
m_order.reset();
TRACE("top_sort",
tout << "DEFINITIONS: " << std::endl;
for(unsigned i = 0; i < m_map.size(); i++)
if(m_map[i]) tout << "VAR " << i << " = " << mk_pp(m_map[i], m_manager) << std::endl;
);
// der::top_sort ts(m_manager);
der_sort_vars(m_inx2var, m_map, m_order);
TRACE("der",
tout << "Elimination m_order:" << std::endl;
for(unsigned i=0; i<m_order.size(); i++)
{
if (i != 0) tout << ",";
tout << m_order[i];
}
tout << std::endl;
);
}
void der::create_substitution(unsigned sz) {
m_subst_map.reset();
m_subst_map.resize(sz, 0);
for(unsigned i = 0; i < m_order.size(); i++) {
expr_ref cur(m_map[m_order[i]], m_manager);
// do all the previous substitutions before inserting
expr_ref r(m_manager);
m_subst(cur, m_subst_map.size(), m_subst_map.c_ptr(), r);
unsigned inx = sz - m_order[i]- 1;
SASSERT(m_subst_map[inx]==0);
m_subst_map[inx] = r;
}
}
void der::apply_substitution(quantifier * q, expr_ref & r) {
expr * e = q->get_expr();
unsigned num_args=to_app(e)->get_num_args();
// get a new expression
m_new_args.reset();
for(unsigned i = 0; i < num_args; i++) {
int x = m_pos2var[i];
if (x != -1 && m_map[x] != 0)
continue; // this is a disequality with definition (vanishes)
m_new_args.push_back(to_app(e)->get_arg(i));
}
unsigned sz = m_new_args.size();
expr_ref t(m_manager);
t = (sz == 1) ? m_new_args[0] : m_manager.mk_or(sz, m_new_args.c_ptr());
expr_ref new_e(m_manager);
m_subst(t, m_subst_map.size(), m_subst_map.c_ptr(), new_e);
// don't forget to update the quantifier patterns
expr_ref_buffer new_patterns(m_manager);
expr_ref_buffer new_no_patterns(m_manager);
for (unsigned j = 0; j < q->get_num_patterns(); j++) {
expr_ref new_pat(m_manager);
m_subst(q->get_pattern(j), m_subst_map.size(), m_subst_map.c_ptr(), new_pat);
new_patterns.push_back(new_pat);
}
for (unsigned j = 0; j < q->get_num_no_patterns(); j++) {
expr_ref new_nopat(m_manager);
m_subst(q->get_no_pattern(j), m_subst_map.size(), m_subst_map.c_ptr(), new_nopat);
new_no_patterns.push_back(new_nopat);
}
r = m_manager.update_quantifier(q, new_patterns.size(), new_patterns.c_ptr(),
new_no_patterns.size(), new_no_patterns.c_ptr(), new_e);
}
struct der_rewriter_cfg : public default_rewriter_cfg {
der m_der;
der_rewriter_cfg(ast_manager & m):m_der(m) {}
ast_manager & m() const { return m_der.m(); }
bool reduce_quantifier(quantifier * old_q,
expr * new_body,
expr * const * new_patterns,
expr * const * new_no_patterns,
expr_ref & result,
proof_ref & result_pr) {
quantifier_ref q1(m());
q1 = m().update_quantifier(old_q, old_q->get_num_patterns(), new_patterns, old_q->get_num_no_patterns(), new_no_patterns, new_body);
m_der(q1, result, result_pr);
return true;
}
};
template class rewriter_tpl<der_rewriter_cfg>;
struct der_rewriter::imp : public rewriter_tpl<der_rewriter_cfg> {
der_rewriter_cfg m_cfg;
imp(ast_manager & m):
rewriter_tpl<der_rewriter_cfg>(m, m.proofs_enabled(), m_cfg),
m_cfg(m) {
}
};
der_rewriter::der_rewriter(ast_manager & m) {
m_imp = alloc(imp, m);
}
der_rewriter::~der_rewriter() {
dealloc(m_imp);
}
ast_manager & der_rewriter::m() const {
return m_imp->m();
}
void der_rewriter::operator()(expr * t, expr_ref & result, proof_ref & result_pr) {
m_imp->operator()(t, result, result_pr);
}
void der_rewriter::set_cancel(bool f) {
#pragma omp critical (der_rewriter)
{
m_imp->set_cancel(f);
}
}
void der_rewriter::cleanup() {
ast_manager & m = m_imp->m();
#pragma omp critical (th_rewriter)
{
dealloc(m_imp);
m_imp = alloc(imp, m);
}
}
void der_rewriter::reset() {
m_imp->reset();
}