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update substitution routines

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2013-01-21 21:47:43 -08:00
parent 7cad0b4a1f
commit b9cc7080e7
3 changed files with 79 additions and 12 deletions
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2
scripts/mk_project.py
View file

@ -22,7 +22,7 @@ def init_project_def():
add_lib('normal_forms', ['rewriter'], 'ast/normal_forms')
add_lib('model', ['rewriter'])
add_lib('tactic', ['ast', 'model'])
add_lib('substitution', ['ast'], 'ast/substitution')
add_lib('substitution', ['ast', 'rewriter'], 'ast/substitution')
add_lib('parser_util', ['ast'], 'parsers/util')
add_lib('grobner', ['ast'], 'math/grobner')
add_lib('euclid', ['util'], 'math/euclid')

66
src/ast/substitution/substitution.cpp
View file

@ -20,22 +20,23 @@ Revision History:
#include"substitution.h"
#include"ast_pp.h"
#include"ast_ll_pp.h"
#include"rewriter.h"
substitution::substitution(ast_manager & m):
m_manager(m),
m_new_exprs(m) {
m_refs(m),
m_new_exprs(m),
m_state(CLEAN) {
}
void substitution::reset() {
reset_subst();
m_subst.reset();
m_vars.reset();
m_refs.reset();
m_scopes.reset();
reset_cache();
}
void substitution::reset_subst() {
m_subst.reset();
m_vars.reset();
m_scopes.reset();
}
void substitution::reset_cache() {
TRACE("subst_bug", tout << "substitution::reset_cache\n";
@ -43,6 +44,7 @@ void substitution::reset_cache() {
m_apply_cache.reset();
m_new_exprs.reset();
m_state = CLEAN;
}
void substitution::pop_scope(unsigned num_scopes) {
@ -57,8 +59,9 @@ void substitution::pop_scope(unsigned num_scopes) {
m_subst.erase(curr.first, curr.second);
}
m_vars.shrink(old_sz);
m_refs.shrink(old_sz);
m_scopes.shrink(new_lvl);
m_apply_cache.reset();
reset_cache();
}
inline void substitution::apply_visit(expr_offset const & n, bool & visited) {
@ -73,11 +76,14 @@ void substitution::apply(unsigned num_actual_offsets, unsigned const * deltas, e
TRACE("subst_bug", tout << "BEGIN substitution::apply\n";);
// It is incorrect to cache results between different calls if we are applying a substitution
// modulo a substitution s -> t.
if (s != expr_offset(0,0))
if (m_state == INSERT || s != expr_offset(0,0))
reset_cache();
m_state = APPLY;
unsigned j;
expr * e;
unsigned off;
@ -161,6 +167,48 @@ void substitution::apply(unsigned num_actual_offsets, unsigned const * deltas, e
}
}
break;
case AST_QUANTIFIER: {
quantifier* q = to_quantifier(e);
unsigned num_vars = q->get_num_decls();
substitution subst(m_manager);
expr_ref er(m_manager);
subst.reserve(m_subst.offsets_capacity(), m_subst.vars_capacity());
var_shifter var_sh(m_manager);
expr_offset r;
for (unsigned i = 0; i < m_subst.offsets_capacity(); i++) {
for (unsigned j = 0; j < m_subst.vars_capacity(); j++) {
if (find(j, i, r)) {
var_sh(r.get_expr(), num_vars, er);
subst.insert(j, i, expr_offset(er, r.get_offset()));
}
}
}
expr_offset body(q->get_expr(), off);
expr_ref s1_ref(m_manager), t1_ref(m_manager);
if (s.get_expr() != 0) {
var_sh(s.get_expr(), num_vars, s1_ref);
}
if (t.get_expr() != 0) {
var_sh(t.get_expr(), num_vars, t1_ref);
}
expr_offset s1(s1_ref, s.get_offset());
expr_offset t1(t1_ref, t.get_offset());
expr_ref_vector pats(m_manager), no_pats(m_manager);
for (unsigned i = 0; i < q->get_num_patterns(); ++i) {
subst.apply(num_actual_offsets, deltas, expr_offset(q->get_pattern(i), off), s1, t1, er);
pats.push_back(er);
}
for (unsigned i = 0; i < q->get_num_no_patterns(); ++i) {
subst.apply(num_actual_offsets, deltas, expr_offset(q->get_no_pattern(i), off), s1, t1, er);
no_pats.push_back(er);
}
subst.apply(num_actual_offsets, deltas, body, s1, t1, er);
er = m_manager.update_quantifier(q, pats.size(), pats.c_ptr(), no_pats.size(), no_pats.c_ptr(), er);
m_todo.pop_back();
m_new_exprs.push_back(er);
m_apply_cache.insert(n, er);
break;
}
default:
UNREACHABLE();
}

23
src/ast/substitution/substitution.h
View file

@ -16,6 +16,19 @@ Author:
Revision History:
nbjorner 2013-01-21:
- reset the apply cache on pop_scope to make sure that popped
substitutions are invalidated.
- reset_cache if a new binding was added after application
of a substitution.
- Add m_refs to make sure terms in the range of the
substitution have the same life-time as the substitution.
- Remove reset_subst() function. If called without resetting the cache, then
results of applying substitutions are incoherent.
- Replace UNREACHABLE segment for quantifiers by recursive invocation of substitution
that updates expressions within quantifiers. It shifts all variables in the domain
of the current substitution by the number of quantified variables.
--*/
#ifndef _SUBSTITUTION_H_
#define _SUBSTITUTION_H_
@ -34,6 +47,7 @@ class substitution {
// field for backtracking
typedef std::pair<unsigned, unsigned> var_offset;
svector<var_offset> m_vars;
expr_ref_vector m_refs;
unsigned_vector m_scopes;
// fields for applying substitutions
@ -45,6 +59,11 @@ class substitution {
enum color { White, Grey, Black };
expr_offset_map<color> m_color;
// keep track of how substitution state was last updated.
enum state { CLEAN, APPLY, INSERT };
state m_state;
#ifdef Z3DEBUG
unsigned m_max_offset_since_reset;
#endif
@ -81,8 +100,6 @@ public:
// reset everything
void reset();
// reset only the mapping from variables to expressions
void reset_subst();
// reset only the substitution application cache
void reset_cache();
@ -119,7 +136,9 @@ public:
TRACE("subst_insert", tout << "inserting: #" << v_idx << ":" << offset << " --> " << mk_pp(t.get_expr(), m_manager)
<< ":" << t.get_offset() << "\n";);
m_vars.push_back(var_offset(v_idx, offset));
m_refs.push_back(t.get_expr());
m_subst.insert(v_idx, offset, t);
m_state = INSERT;
}
void insert(var * v, unsigned offset, expr_offset const & t) { insert(v->get_idx(), offset, t); }
void insert(expr_offset v, expr_offset const & t) {