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Move language containment into ltl_simplifier.

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* src/ltlvisit/simplify.cc: Integrate the tau03
containment rules.
* src/ltlvisit/simplify.hh: Add options to select simplifications.
* src/ltlvisit/reduce.cc (reduce): Do not call reduce_tau03().
* src/ltlvisit/contain.cc (reduce_tau03_visitor): Remove.
(reduce_tau03): Implement it using ltl_simplifier.
This commit is contained in:
Alexandre Duret-Lutz 2011-08-24 15:54:06 +02:00
parent 82b42494db
commit 1087c62356
4 changed files with 442 additions and 539 deletions
Download patch file Download diff file Expand all files Collapse all files

264
src/ltlvisit/contain.cc
View file

@ -22,6 +22,7 @@
// 02111-1307, USA. // 02111-1307, USA.
#include "contain.hh" #include "contain.hh"
#include "simplify.hh"
#include "tunabbrev.hh" #include "tunabbrev.hh"
#include "ltlast/unop.hh" #include "ltlast/unop.hh"
#include "ltlast/binop.hh" #include "ltlast/binop.hh"
@ -144,271 +145,16 @@ namespace spot
} }
namespace
{
struct reduce_tau03_visitor : public clone_visitor {
bool stronger;
language_containment_checker* lcc;
reduce_tau03_visitor(bool stronger,
language_containment_checker* lcc)
: stronger(stronger), lcc(lcc)
{
}
void
visit(unop* uo)
{
formula* a = recurse(uo->child());
switch (uo->op())
{
case unop::X:
// if X(a) = a, then keep only a !
if (stronger && lcc->equal(a, uo))
{
result_ = a;
break;
}
default:
result_ = unop::instance(uo->op(), a);
}
}
void
visit(binop* bo)
{
formula* a = recurse(bo->first());
formula* b = recurse(bo->second());
switch (bo->op())
{
case binop::U:
// if (a U b) => b, then keep b !
if (stronger && lcc->contained(bo, b))
{
a->destroy();
result_ = b;
}
// if a => b, then a U b = b.
else if ((!stronger) && lcc->contained(a, b))
{
a->destroy();
result_ = b;
}
// if !a => b, then a U b = Fb
else if (lcc->neg_contained(a, b))
{
a->destroy();
result_ = unop::instance(unop::F, b);
}
else
{
result_ = binop::instance(binop::U, a, b);
}
break;
case binop::W:
// if (a W b) => b, then keep b !
if (stronger && lcc->contained(bo, b))
{
a->destroy();
result_ = b;
}
// if a => b, then a W b = b.
else if ((!stronger) && lcc->contained(a, b))
{
a->destroy();
result_ = b;
}
// if !a => b, then a W b = 1
else if (lcc->neg_contained(a, b))
{
a->destroy();
b->destroy();
result_ = constant::true_instance();
}
else
{
result_ = binop::instance(binop::W, a, b);
}
break;
case binop::R:
// if b => a, then a R b = b.
if (lcc->contained(b, a))
{
a->destroy();
result_ = b;
}
// if a => !b, then a R b = Gb
else if (lcc->contained_neg(a, b))
{
a->destroy();
result_ = unop::instance(unop::G, b);
}
else
{
result_ = binop::instance(binop::R, a, b);
}
break;
case binop::M:
// if b => a, then a M b = b.
if (lcc->contained(b, a))
{
a->destroy();
result_ = b;
}
// if a => !b, then a M b = 0
else if (lcc->contained_neg(a, b))
{
a->destroy();
b->destroy();
result_ = constant::false_instance();
}
else
{
result_ = binop::instance(binop::M, a, b);
}
break;
default:
result_ = binop::instance(bo->op(), a, b);
}
}
void
visit(automatop*)
{
assert(0);
}
void
visit(multop* mo)
{
multop::vec* res = new multop::vec;
unsigned mos = mo->size();
for (unsigned i = 0; i < mos; ++i)
res->push_back(recurse(mo->nth(i)));
result_ = 0;
bool changed = false;
switch (mo->op())
{
case multop::Or:
for (unsigned i = 0; i < mos; ++i)
{
if (!(*res)[i])
continue;
for (unsigned j = i + 1; j < mos; ++j)
{
if (!(*res)[j])
continue;
// if !i => j, then i|j = true
if (lcc->neg_contained((*res)[i], (*res)[j]))
{
result_ = constant::true_instance();
goto constant_;
}
// if i => j, then i|j = j
else if (lcc->contained((*res)[i], (*res)[j]))
{
(*res)[i]->destroy();
(*res)[i] = 0;
changed = true;
break;
}
// if j => i, then i|j = i
else if (lcc->contained((*res)[j], (*res)[i]))
{
(*res)[j]->destroy();
(*res)[j] = 0;
changed = true;
}
}
}
break;
case multop::And:
for (unsigned i = 0; i < mos; ++i)
{
if (!(*res)[i])
continue;
for (unsigned j = i + 1; j < mos; ++j)
{
if (!(*res)[j])
continue;
// if i => !j, then i&j = false
if (lcc->contained_neg((*res)[i], (*res)[j]))
{
result_ = constant::false_instance();
goto constant_;
}
// if i => j, then i&j = i
else if (lcc->contained((*res)[i], (*res)[j]))
{
(*res)[j]->destroy();
(*res)[j] = 0;
changed = true;
}
// if j => i, then i&j = j
else if (lcc->contained((*res)[j], (*res)[i]))
{
(*res)[i]->destroy();
(*res)[i] = 0;
changed = true;
break;
}
}
}
break;
case multop::Concat:
case multop::Fusion:
case multop::AndNLM:
break;
}
if (changed)
{
multop::vec* nres = new multop::vec;
for (unsigned i = 0; i < mos; ++i)
if ((*res)[i])
nres->push_back((*res)[i]);
delete res;
res = nres;
}
result_ = multop::instance(mo->op(), res);
return;
constant_:
for (unsigned i = 0; i < mos; ++i)
if ((*res)[i])
(*res)[i]->destroy();
delete res;
}
formula*
recurse(formula* f)
{
if (!f->is_psl_formula())
return f->clone();
reduce_tau03_visitor v(stronger, lcc);
const_cast<formula*>(f)->accept(v);
return v.result();
}
};
}
formula* formula*
reduce_tau03(const formula* f, bool stronger) reduce_tau03(const formula* f, bool stronger)
{ {
if (!f->is_psl_formula()) if (!f->is_psl_formula())
return f->clone(); return f->clone();
bdd_dict b; ltl_simplifier_options opt(false, false, false,
reduce_tau03_visitor v(stronger, true, stronger);
new language_containment_checker(&b, ltl_simplifier simpl(opt);
true, true, return simpl.simplify(f);
false, false));
// reduce_tau03_visitor does not handle Xor, Implies, and Equiv.
f = unabbreviate_ltl(f);
const_cast<formula*>(f)->accept(v);
f->destroy();
delete v.lcc;
return v.result();
} }
} }
} }

15
src/ltlvisit/reduce.cc
View file

@ -28,7 +28,6 @@
#include "lunabbrev.hh" #include "lunabbrev.hh"
#include "simpfg.hh" #include "simpfg.hh"
#include "nenoform.hh" #include "nenoform.hh"
#include "contain.hh"
#include "simplify.hh" #include "simplify.hh"
namespace spot namespace spot
@ -73,20 +72,8 @@ namespace spot
f2->destroy(); f2->destroy();
f2 = f1; f2 = f1;
f1 = simplifier.simplify(f2); f = simplifier.simplify(f2);
f2->destroy(); f2->destroy();
f2 = f1;
if (opt & (Reduce_Containment_Checks
| Reduce_Containment_Checks_Stronger))
{
formula* f1 =
reduce_tau03(f2,
opt & Reduce_Containment_Checks_Stronger);
f2->destroy();
f2 = f1;
}
f = f2;
} }
prev->destroy(); prev->destroy();

537
src/ltlvisit/simplify.cc
View file

@ -18,6 +18,14 @@
// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA // Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA. // 02111-1307, USA.
#include <iostream>
//#define TRACE
#ifdef TRACE
#define trace std::cerr
#else
#define trace while (0) std::cerr
#endif
#include "simplify.hh" #include "simplify.hh"
#include "misc/hash.hh" #include "misc/hash.hh"
@ -25,6 +33,8 @@
#include "ltlast/allnodes.hh" #include "ltlast/allnodes.hh"
#include "ltlast/visitor.hh" #include "ltlast/visitor.hh"
#include "ltlvisit/syntimpl.hh" #include "ltlvisit/syntimpl.hh"
#include "ltlvisit/contain.hh"
#include "ltlvisit/tostring.hh"
#include <cassert> #include <cassert>
namespace spot namespace spot
@ -40,8 +50,10 @@ namespace spot
typedef Sgi::hash_map<const formula*, bdd, typedef Sgi::hash_map<const formula*, bdd,
ptr_hash<formula> > f2b_map; ptr_hash<formula> > f2b_map;
public: public:
bdd_dict dict;
ltl_simplifier_options options; ltl_simplifier_options options;
syntactic_implication_cache syntimpl; syntactic_implication_cache syntimpl;
language_containment_checker lcc;
~ltl_simplifier_cache() ~ltl_simplifier_cache()
{ {
@ -79,11 +91,14 @@ namespace spot
} }
ltl_simplifier_cache() ltl_simplifier_cache()
: lcc(&dict, true, true, false, false)
{ {
} }
ltl_simplifier_cache(ltl_simplifier_options opt) : options(opt) ltl_simplifier_cache(ltl_simplifier_options opt)
: options(opt), lcc(&dict, true, true, false, false)
{ {
opt.containment_checks |= opt.containment_checks_stronger;
} }
// Convert a Boolean formula into a BDD for easier comparison. // Convert a Boolean formula into a BDD for easier comparison.
@ -193,19 +208,126 @@ namespace spot
nenoform_[orig->clone()] = nenoform->clone(); nenoform_[orig->clone()] = nenoform->clone();
} }
// Return true if f1 < f2 (i.e. f1 implies f2 syntactically) // Return true iff the option set (syntactic implication
// or containment checks) allow to prove that f1 => f2.
bool
implication(const formula* f1, const formula* f2)
{
return (options.synt_impl && syntactic_implication(f1, f2))
|| (options.containment_checks && contained(f1, f2));
}
// Return true if f1 => f2 syntactically
bool bool
syntactic_implication(const formula* f1, const formula* f2) syntactic_implication(const formula* f1, const formula* f2)
{ {
// We cannot run syntactic_implication on SERE formulae,
// except on Boolean formulae.
if (f1->is_sere_formula() && !f1->is_boolean())
return false;
if (f2->is_sere_formula() && !f2->is_boolean())
return false;
return syntimpl.syntactic_implication(f1, f2); return syntimpl.syntactic_implication(f1, f2);
} }
// If right==false, true if !f1 < f2, false otherwise. // Return true if f1 => f2
// If right==true, true if f1 < !f2, false otherwise. bool
bool syntactic_implication_neg(const formula* f1, const formula* f2, contained(const formula* f1, const formula* f2)
{
if (!f1->is_psl_formula() || !f2->is_psl_formula())
return false;
return lcc.contained(f1, f2);
}
// If right==false, true if !f1 => f2, false otherwise.
// If right==true, true if f1 => !f2, false otherwise.
bool
syntactic_implication_neg(const formula* f1, const formula* f2,
bool right) bool right)
{ {
return syntimpl.syntactic_implication_neg(f1, f2, right); // We cannot run syntactic_implication_neg on SERE formulae,
// except on Boolean formulae.
if (f1->is_sere_formula() && !f1->is_boolean())
return false;
if (f2->is_sere_formula() && !f2->is_boolean())
return false;
trace << "[SIN] Does " << (right ? "(" : "!(")
<< to_string(f1) << ") implies "
<< (right ? "!(" : "(") << to_string(f2) << ") ?"
<< std::endl;
if (syntimpl.syntactic_implication_neg(f1, f2, right))
{
trace << "[SIN] Yes" << std::endl;
return true;
}
else
{
trace << "[SIN] No" << std::endl;
return false;
}
}
// Return true if f1 => !f2
bool contained_neg(const formula* f1, const formula* f2)
{
if (!f1->is_psl_formula() || !f2->is_psl_formula())
return false;
trace << "[CN] Does (" << to_string(f1) << ") implies !("
<< to_string(f2) << ") ?" << std::endl;
if (lcc.contained_neg(f1, f2))
{
trace << "[CN] Yes" << std::endl;
return true;
}
else
{
trace << "[CN] No" << std::endl;
return false;
}
}
// Return true if f1 => !f2
bool neg_contained(const formula* f1, const formula* f2)
{
if (!f1->is_psl_formula() || !f2->is_psl_formula())
return false;
trace << "[NC] Does (" << to_string(f1) << ") implies !("
<< to_string(f2) << ") ?" << std::endl;
if (lcc.neg_contained(f1, f2))
{
trace << "[NC] Yes" << std::endl;
return true;
}
else
{
trace << "[NC] No" << std::endl;
return false;
}
}
// Return true iff the option set (syntactic implication
// or containment checks) allow to prove that
// - !f2 => f2 (case where right=false)
// - f1 => !f2 (case where right=true)
bool
implication_neg(const formula* f1, const formula* f2, bool right)
{
trace << "[IN] Does " << (right ? "(" : "!(")
<< to_string(f1) << ") implies "
<< (right ? "!(" : "(") << to_string(f2) << ") ?"
<< std::endl;
if ((options.synt_impl && syntactic_implication_neg(f1, f2, right))
|| (options.containment_checks && right && contained_neg(f1, f2))
|| (options.containment_checks && !right && neg_contained(f1, f2)))
{
trace << "[IN] Yes" << std::endl;
return true;
}
else
{
trace << "[IN] No" << std::endl;
return false;
}
} }
const formula* const formula*
@ -788,10 +910,13 @@ namespace spot
init(); init();
multop::vec::const_iterator end = v->end(); multop::vec::const_iterator end = v->end();
for (multop::vec::const_iterator i = v->begin(); i < end; ++i) for (multop::vec::const_iterator i = v->begin(); i < end; ++i)
{
if (*i) // skip null pointers left by previous simplifications
{ {
process(*i); process(*i);
(*i)->destroy(); (*i)->destroy();
} }
}
delete v; delete v;
} }
@ -891,10 +1016,17 @@ namespace spot
// XGF(f) = GF(f) and XFG(f) = FG(f) // XGF(f) = GF(f) and XFG(f) = FG(f)
// The former comes from Somenzi&Bloem (CAV'00). // The former comes from Somenzi&Bloem (CAV'00).
// It's not clear why they do not list the second. // It's not clear why they do not list the second.
if (is_GF(result_) || is_FG(result_)) if (opt_.reduce_basics &&
(is_GF(result_) || is_FG(result_)))
return; return;
} }
// If Xa = a, keep only a.
if (opt_.containment_checks_stronger
&& c_->lcc.equal(result_, uo))
return;
// Disabled: X(f1 & GF(f2)) = X(f1) & GF(f2) // Disabled: X(f1 & GF(f2)) = X(f1) & GF(f2)
// Disabled: X(f1 | GF(f2)) = X(f1) | GF(f2) // Disabled: X(f1 | GF(f2)) = X(f1) | GF(f2)
// Disabled: X(f1 & FG(f2)) = X(f1) & FG(f2) // Disabled: X(f1 & FG(f2)) = X(f1) & FG(f2)
@ -914,11 +1046,9 @@ namespace spot
if (opt_.event_univ && result_->is_eventual()) if (opt_.event_univ && result_->is_eventual())
return; return;
if (!opt_.reduce_basics) if (opt_.reduce_basics)
break;
// F(a U b) = F(b)
{ {
// F(a U b) = F(b)
binop* bo = is_U(result_); binop* bo = is_U(result_);
if (bo) if (bo)
{ {
@ -928,7 +1058,6 @@ namespace spot
result_ = recurse_destroy(r); result_ = recurse_destroy(r);
return; return;
} }
}
// FX(a) = XF(a) // FX(a) = XF(a)
{ {
@ -944,6 +1073,12 @@ namespace spot
return; return;
} }
} }
}
// if Fa => a, keep a.
if (opt_.containment_checks_stronger
&& c_->lcc.contained(uo, result_))
return;
// Disabled: F(f1 & GF(f2)) = F(f1) & GF(f2) // Disabled: F(f1 & GF(f2)) = F(f1) & GF(f2)
// //
@ -972,8 +1107,8 @@ namespace spot
if (opt_.event_univ && result_->is_universal()) if (opt_.event_univ && result_->is_universal())
return; return;
if (!opt_.reduce_basics) if (opt_.reduce_basics)
break; {
// G(a R b) = G(b) // G(a R b) = G(b)
if (result_->kind() == formula::BinOp) if (result_->kind() == formula::BinOp)
@ -1013,22 +1148,38 @@ namespace spot
multop* mo = static_cast<multop*>(result_); multop* mo = static_cast<multop*>(result_);
if (mo->op() == multop::Or) if (mo->op() == multop::Or)
{ {
mo->clone();
mospliter s(mospliter::Strip_GF | mospliter s(mospliter::Strip_GF |
mospliter::Split_EventUniv, mospliter::Split_EventUniv,
mo, c_); mo, c_);
s.res_EventUniv->push_back(unop_multop(unop::G, s.res_EventUniv->
multop::Or, push_back(unop_multop(unop::G, multop::Or,
s.res_other)); s.res_other));
s.res_EventUniv->push_back(unop_unop_multop(unop::G, s.res_EventUniv->
unop::F, push_back(unop_unop_multop(unop::G, unop::F,
multop::Or, multop::Or, s.res_GF));
s.res_GF)); result_ = multop::instance(multop::Or,
result_ = multop::instance(multop::Or, s.res_EventUniv); s.res_EventUniv);
if (result_ != uo) if (result_ != uo)
{
mo->destroy();
result_ = recurse_destroy(result_); result_ = recurse_destroy(result_);
return; return;
} }
else
{
// Revert to the previous value of result_,
// for the next simplification.
result_->destroy();
result_ = mo;
} }
}
}
}
// if a => Ga, keep a.
if (opt_.containment_checks_stronger
&& c_->lcc.contained(result_, uo))
return;
break; break;
case unop::Finish: case unop::Finish:
case unop::Closure: case unop::Closure:
@ -1044,50 +1195,51 @@ namespace spot
{ {
binop::type op = bo->op(); binop::type op = bo->op();
formula* f2 = recurse(bo->second()); formula* b = recurse(bo->second());
if (opt_.event_univ) if (opt_.event_univ)
{ {
/* If b is a pure eventuality formula then a U b = b. /* If b is a pure eventuality formula then a U b = b.
If b is a pure universality formula a R b = b. */ If b is a pure universality formula a R b = b. */
if ((f2->is_eventual() && (op == binop::U)) if ((b->is_eventual() && (op == binop::U))
|| (f2->is_universal() && (op == binop::R))) || (b->is_universal() && (op == binop::R)))
{ {
result_ = f2; result_ = b;
return; return;
} }
} }
formula* f1 = recurse(bo->first()); formula* a = recurse(bo->first());
if (opt_.event_univ) if (opt_.event_univ)
{ {
/* If a is a pure eventuality formula then a M b = a & b. /* If a is a pure eventuality formula then a M b = a & b.
If a is a pure universality formula a W b = a|b. */ If a is a pure universality formula a W b = a|b. */
if (f1->is_eventual() && (op == binop::M)) if (a->is_eventual() && (op == binop::M))
{ {
formula* tmp = multop::instance(multop::And, f1, f2); formula* tmp = multop::instance(multop::And, a, b);
result_ = recurse(tmp); result_ = recurse(tmp);
tmp->destroy(); tmp->destroy();
return; return;
} }
if (f1->is_universal() && (op == binop::W)) if (a->is_universal() && (op == binop::W))
{ {
formula* tmp = multop::instance(multop::Or, f1, f2); formula* tmp = multop::instance(multop::Or, a, b);
result_ = recurse(tmp); result_ = recurse(tmp);
tmp->destroy(); tmp->destroy();
return; return;
} }
} }
/* case of implies */ // Inclusion-based rules
if (opt_.synt_impl) if (opt_.synt_impl | opt_.containment_checks)
{ {
switch (op) switch (op)
{ {
case binop::Xor: case binop::Xor:
case binop::Equiv: case binop::Equiv:
case binop::Implies: case binop::Implies:
assert(!"operator not supported for syntactic implication"); assert(!"operator not supported for implication rules");
return; return;
case binop::UConcat: case binop::UConcat:
case binop::EConcat: case binop::EConcat:
@ -1095,141 +1247,150 @@ namespace spot
break; break;
case binop::U: case binop::U:
/* a < b => a U b = b */ // if a => b, then a U b = b
if (c_->syntactic_implication(f1, f2)) // if (a U b) => b, then a U b = b (for stronger containment)
if (c_->implication(a, b)
|| (opt_.containment_checks_stronger
&& c_->contained(bo, b)))
{ {
result_ = f2; a->destroy();
f1->destroy(); result_ = b;
return; return;
} }
/* !b < a => a U b = Fb */ // if !a => b, then a U b = Fb
if (c_->syntactic_implication_neg(f2, f1, false)) if (c_->implication_neg(a, b, false))
{ {
result_ = unop::instance(unop::F, f2); a->destroy();
f1->destroy(); result_ =
recurse_destroy(unop::instance(unop::F, b));
return; return;
} }
/* a < b => a U (b U c) = (b U c) */ // if a => b, then a U (b U c) = (b U c)
/* a < b => a U (b W c) = (b W c) */ // if a => b, then a U (b W c) = (b W c)
if (f2->kind() == formula::BinOp) if (b->kind() == formula::BinOp)
{ {
binop* bo = static_cast<binop*>(f2); binop* bo = static_cast<binop*>(b);
if ((bo->op() == binop::U || bo->op() == binop::W) if ((bo->op() == binop::U || bo->op() == binop::W)
&& c_->syntactic_implication(f1, bo->first())) && c_->implication(a, bo->first()))
{ {
result_ = f2; a->destroy();
f1->destroy(); result_ = b;
return; return;
} }
} }
break; break;
case binop::R: case binop::R:
/* b < a => a R b = b */ // if b => a, then a R b = b
if (c_->syntactic_implication(f2, f1)) if (c_->implication(b, a))
{ {
result_ = f2; a->destroy();
f1->destroy(); result_ = b;
return; return;
} }
/* b < !a => a R b = Gb */ // if b => !a, then a R b = Gb
if (c_->syntactic_implication_neg(f2, f1, true)) if (c_->implication_neg(b, a, true))
{ {
result_ = unop::instance(unop::G, f2); a->destroy();
f1->destroy(); result_ = unop::instance(unop::G, b);
return; return;
} }
if (f2->kind() == formula::BinOp) if (b->kind() == formula::BinOp)
{ {
/* b < a => a R (b R c) = b R c */ // if b => a, then a R (b R c) = b R c
/* b < a => a R (b M c) = b M c */ // if b => a, then a R (b M c) = b M c
binop* bo = static_cast<binop*>(f2); binop* bo = static_cast<binop*>(b);
if ((bo->op() == binop::R || bo->op() == binop::M) if ((bo->op() == binop::R || bo->op() == binop::M)
&& c_->syntactic_implication(bo->first(), f1)) && c_->implication(bo->first(), a))
{ {
result_ = f2; a->destroy();
f1->destroy(); result_ = b;
return; return;
} }
/* a < b => a R (b R c) = a R c */ // if a => b, then a R (b R c) = a R c
if (bo->op() == binop::R if (bo->op() == binop::R
&& c_->syntactic_implication(f1, bo->first())) && c_->implication(a, bo->first()))
{ {
result_ = binop::instance(binop::R, f1, b->destroy();
bo->second()->clone()); result_ = recurse_destroy
f2->destroy(); (binop::instance(binop::R, a,
bo->second()->clone()));
return; return;
} }
} }
break; break;
case binop::W: case binop::W:
/* a < b => a W b = b */ // if a => b, then a W b = b
if (c_->syntactic_implication(f1, f2)) // if a W b => b, then a W b = b (for stronger containment)
if (c_->implication(a, b)
|| (opt_.containment_checks_stronger
&& c_->contained(bo, b)))
{ {
result_ = f2; a->destroy();
f1->destroy(); result_ = b;
return; return;
} }
/* !b < a => a W b = 1 */ // if !a => b then a W b = 1
if (c_->syntactic_implication_neg(f2, f1, false)) if (c_->implication_neg(a, b, false))
{ {
a->destroy();
b->destroy();
result_ = constant::true_instance(); result_ = constant::true_instance();
f1->destroy();
f2->destroy();
return; return;
} }
/* a < b => a W (b W c) = (b W c) */ // if a => b, then a W (b W c) = (b W c)
if (f2->kind() == formula::BinOp) if (b->kind() == formula::BinOp)
{ {
binop* bo = static_cast<binop*>(f2); binop* bo = static_cast<binop*>(b);
if (bo->op() == binop::W if (bo->op() == binop::W
&& c_->syntactic_implication(f1, bo->first())) && c_->implication(a, bo->first()))
{ {
result_ = f2; a->destroy();
f1->destroy(); result_ = b;
return; return;
} }
} }
break; break;
case binop::M: case binop::M:
/* b < a => a M b = b */ // if b => a, then a M b = b
if (c_->syntactic_implication(f2, f1)) if (c_->implication(b, a))
{ {
result_ = f2; a->destroy();
f1->destroy(); result_ = b;
return; return;
} }
/* b < !a => a M b = 0 */ // if b => !a, then a M b = 0
if (c_->syntactic_implication_neg(f2, f1, true)) if (c_->implication_neg(b, a, true))
{ {
a->destroy();
b->destroy();
result_ = constant::false_instance(); result_ = constant::false_instance();
f1->destroy();
f2->destroy();
return; return;
} }
if (f2->kind() == formula::BinOp) if (b->kind() == formula::BinOp)
{ {
/* b < a => a M (b M c) = b M c */ // if b => a, then a M (b M c) = b M c
binop* bo = static_cast<binop*>(f2); binop* bo = static_cast<binop*>(b);
if (bo->op() == binop::M if (bo->op() == binop::M
&& c_->syntactic_implication(bo->first(), f1)) && c_->implication(bo->first(), a))
{ {
result_ = f2; result_ = b;
f1->destroy(); a->destroy();
return; return;
} }
/* a < b => a M (b M c) = a M c */ // if a => b, then a M (b M c) = a M c
/* a < b => a M (b R c) = a M c */ // if a => b, then a M (b R c) = a M c
if ((bo->op() == binop::M || bo->op() == binop::R) if ((bo->op() == binop::M || bo->op() == binop::R)
&& c_->syntactic_implication(f1, bo->first())) && c_->implication(a, bo->first()))
{ {
result_ = binop::instance(binop::M, f1, b->destroy();
bo->second()->clone()); result_ = recurse_destroy
f2->destroy(); (binop::instance(binop::M, a,
bo->second()->clone()));
return; return;
} }
} }
@ -1237,39 +1398,44 @@ namespace spot
} }
} }
if (!opt_.reduce_basics)
{
result_ = binop::instance(op, a, b);
return;
}
// Rewrite U,R,W,M as F or G when possible. // Rewrite U,R,W,M as F or G when possible.
switch (op) switch (op)
{ {
case binop::U: case binop::U:
// true U f2 == F(f2) // true U b == F(b)
if (f1 == constant::true_instance()) if (a == constant::true_instance())
{ {
result_ = recurse_destroy(unop::instance(unop::F, f2)); result_ = recurse_destroy(unop::instance(unop::F, b));
return; return;
} }
break; break;
case binop::R: case binop::R:
// false R f2 == G(f2) // false R b == G(b)
if (f1 == constant::false_instance()) if (a == constant::false_instance())
{ {
result_ = recurse_destroy(unop::instance(unop::G, f2)); result_ = recurse_destroy(unop::instance(unop::G, b));
return; return;
} }
break; break;
case binop::W: case binop::W:
// f1 W false == G(f1) // a W false == G(a)
if (f2 == constant::false_instance()) if (b == constant::false_instance())
{ {
result_ = recurse_destroy(unop::instance(unop::G, f1)); result_ = recurse_destroy(unop::instance(unop::G, a));
return; return;
} }
break; break;
case binop::M: case binop::M:
// f1 M true == F(f1) // a M true == F(a)
if (f2 == constant::false_instance()) if (b == constant::false_instance())
{ {
result_ = recurse_destroy(unop::instance(unop::F, f1)); result_ = recurse_destroy(unop::instance(unop::F, a));
return; return;
} }
break; break;
@ -1291,18 +1457,18 @@ namespace spot
// a R true = true // a R true = true
// a W true = true // a W true = true
// a M false = false // a M false = false
if (is_constant(f2)) if (is_constant(b))
{ {
result_ = f2; result_ = b;
f1->destroy(); a->destroy();
return; return;
} }
// Same effect as dynamic_cast<unop*>, only faster. // Same effect as dynamic_cast<unop*>, only faster.
unop* fu1 = unop* fu1 =
(f1->kind() == formula::UnOp) ? static_cast<unop*>(f1) : 0; (a->kind() == formula::UnOp) ? static_cast<unop*>(a) : 0;
unop* fu2 = unop* fu2 =
(f2->kind() == formula::UnOp) ? static_cast<unop*>(f2) : 0; (b->kind() == formula::UnOp) ? static_cast<unop*>(b) : 0;
// X(a) U X(b) = X(a U b) // X(a) U X(b) = X(a U b)
// X(a) R X(b) = X(a R b) // X(a) R X(b) = X(a R b)
@ -1315,8 +1481,8 @@ namespace spot
formula* bin = binop::instance(op, formula* bin = binop::instance(op,
fu1->child()->clone(), fu1->child()->clone(),
fu2->child()->clone()); fu2->child()->clone());
f1->destroy(); a->destroy();
f2->destroy(); b->destroy();
result_ = recurse_destroy(unop::instance(unop::X, bin)); result_ = recurse_destroy(unop::instance(unop::X, bin));
return; return;
} }
@ -1325,18 +1491,18 @@ namespace spot
{ {
// a U Ga = Ga // a U Ga = Ga
// a W Ga = Ga // a W Ga = Ga
if (fu2 && fu2->op() == unop::G && fu2->child() == f1) if (fu2 && fu2->op() == unop::G && fu2->child() == a)
{ {
f1->destroy(); a->destroy();
result_ = f2; result_ = b;
return; return;
} }
// a U (b | c | G(a)) = a W (b | c) // a U (b | c | G(a)) = a W (b | c)
// a W (b | c | G(a)) = a W (b | c) // a W (b | c | G(a)) = a W (b | c)
if (f2->kind() == formula::MultOp) if (b->kind() == formula::MultOp)
{ {
multop* fm2 = static_cast<multop*>(f2); multop* fm2 = static_cast<multop*>(b);
if (fm2->op() == multop::Or) if (fm2->op() == multop::Or)
{ {
int s = fm2->size(); int s = fm2->size();
@ -1345,7 +1511,7 @@ namespace spot
if (fm2->nth(i)->kind() != formula::UnOp) if (fm2->nth(i)->kind() != formula::UnOp)
continue; continue;
unop* c = static_cast<unop*>(fm2->nth(i)); unop* c = static_cast<unop*>(fm2->nth(i));
if (c->op() == unop::G && c->child() == f1) if (c->op() == unop::G && c->child() == a)
{ {
multop::vec* v = new multop::vec; multop::vec* v = new multop::vec;
v->reserve(s - 1); v->reserve(s - 1);
@ -1355,9 +1521,9 @@ namespace spot
// skip j=i // skip j=i
for (++j; j < s; ++j) for (++j; j < s; ++j)
v->push_back(fm2->nth(j)->clone()); v->push_back(fm2->nth(j)->clone());
f2->destroy(); b->destroy();
result_ = recurse_destroy(binop::instance result_ = recurse_destroy(binop::instance
(binop::W, f1, (binop::W, a,
multop::instance(multop::Or, v))); multop::instance(multop::Or, v)));
return; return;
} }
@ -1369,18 +1535,18 @@ namespace spot
{ {
// a R Fa = Fa // a R Fa = Fa
// a M Fa = Fa // a M Fa = Fa
if (fu2 && fu2->op() == unop::F && fu2->child() == f1) if (fu2 && fu2->op() == unop::F && fu2->child() == a)
{ {
f1->destroy(); a->destroy();
result_ = f2; result_ = b;
return; return;
} }
// a R (b & c & F(a)) = a M b // a R (b & c & F(a)) = a M b
// a M (b & c & F(a)) = a M b // a M (b & c & F(a)) = a M b
if (f2->kind() == formula::MultOp) if (b->kind() == formula::MultOp)
{ {
multop* fm2 = static_cast<multop*>(f2); multop* fm2 = static_cast<multop*>(b);
if (fm2->op() == multop::And) if (fm2->op() == multop::And)
{ {
int s = fm2->size(); int s = fm2->size();
@ -1389,7 +1555,7 @@ namespace spot
if (fm2->nth(i)->kind() != formula::UnOp) if (fm2->nth(i)->kind() != formula::UnOp)
continue; continue;
unop* c = static_cast<unop*>(fm2->nth(i)); unop* c = static_cast<unop*>(fm2->nth(i));
if (c->op() == unop::F && c->child() == f1) if (c->op() == unop::F && c->child() == a)
{ {
multop::vec* v = new multop::vec; multop::vec* v = new multop::vec;
v->reserve(s - 1); v->reserve(s - 1);
@ -1399,9 +1565,9 @@ namespace spot
// skip j=i // skip j=i
for (++j; j < s; ++j) for (++j; j < s; ++j)
v->push_back(fm2->nth(j)->clone()); v->push_back(fm2->nth(j)->clone());
f2->destroy(); b->destroy();
result_ = recurse_destroy(binop::instance result_ = recurse_destroy(binop::instance
(binop::M, f1, (binop::M, a,
multop::instance(multop::And, v))); multop::instance(multop::And, v)));
return; return;
} }
@ -1416,11 +1582,11 @@ namespace spot
case binop::EConcat: case binop::EConcat:
case binop::UConcat: case binop::UConcat:
case binop::EConcatMarked: case binop::EConcatMarked:
// No simplification. // No simplification... Yet?
break; break;
} }
result_ = binop::instance(op, f1, f2); result_ = binop::instance(op, a, b);
} }
void void
@ -1440,77 +1606,74 @@ namespace spot
multop::type op = mo->op(); multop::type op = mo->op();
if ((opt_.synt_impl) if ((opt_.synt_impl | opt_.containment_checks)
&& (op != multop::Concat) && (op != multop::Concat)
&& (op != multop::Fusion)) && (op != multop::Fusion))
{ {
bool is_and = op != multop::Or; // And or AndNLM
constant* neutral = is_and
? constant::false_instance() : constant::true_instance();
bool removed = true; multop::vec::iterator f1 = res->begin();
multop::vec::iterator f1;
multop::vec::iterator f2;
while (removed)
{
removed = false;
f2 = f1 = res->begin();
++f1;
while (f1 != res->end()) while (f1 != res->end())
{ {
assert(f1 != f2); multop::vec::iterator f2 = f1;
// a < b => a + b = b ++f2
// a < b => a & b = a ;
if ((c_->syntactic_implication(*f1, *f2) && // f1 < f2 while (f2 != res->end())
(mo->op() == multop::Or)) ||
((c_->syntactic_implication(*f2, *f1)) && // f2 < f1
(mo->op() == multop::And)))
{ {
// We keep f2 assert(f1 != f2);
// if f1 => f2, then f1 | f2 = f2
// if f2 => f1, then f1 & f2 = f2
if ((op == multop::Or && c_->implication(*f1, *f2))
|| (op == multop::And && c_->implication(*f2, *f1)))
{
// Remove f1.
(*f1)->destroy(); (*f1)->destroy();
res->erase(f1); *f1 = 0;
removed = true; ++f1;
break; break;
} }
else if ((c_->syntactic_implication(*f2, *f1) // f2 < f1 // if f2 => f1, then f1 | f2 = f1
&& (mo->op() == multop::Or)) || // if f1 => f2, then f1 & f2 = f1
((c_->syntactic_implication(*f1, *f2)) // f1 < f2 else if ((op == multop::Or && c_->implication(*f2, *f1))
&& (mo->op() == multop::And))) || (op == multop::And
&& c_->implication(*f1, *f2)))
{ {
// We keep f1 // Remove f2.
(*f2)->destroy(); (*f2)->destroy();
res->erase(f2); // replace it by the last element from the array.
removed = true; // and start again at the current position.
break; if (f2 != --res->end())
{
*f2 = res->back();
res->pop_back();
continue;
} }
else else
++f1;
}
}
// We cannot run syntactic_implication_neg on SERE
// formulae, unless they are just Boolean formulae.
if (mo->is_boolean() || !mo->is_sere_formula())
{ {
bool is_and = mo->op() != multop::Or; res->pop_back();
/* f1 < !f2 => f1 & f2 = false break;
!f1 < f2 => f1 | f2 = true */ }
for (f1 = res->begin(); f1 != res->end(); f1++) }
for (f2 = res->begin(); f2 != res->end(); f2++) // if f1 => !f2, then f1 & f2 = false
if (f1 != f2 && // if !f1 => f2, then f1 | f2 = true
c_->syntactic_implication_neg(*f1, *f2, is_and)) else if (c_->implication_neg(*f1, *f2, is_and))
{ {
for (multop::vec::iterator j = res->begin(); for (multop::vec::iterator j = res->begin();
j != res->end(); j++) j != res->end(); j++)
if (*j)
(*j)->destroy(); (*j)->destroy();
res->clear();
delete res; delete res;
if (is_and) result_ = neutral;
result_ = constant::false_instance();
else
result_ = constant::true_instance();
return; return;
} }
else
++f2;
}
++f1;
} }
} }
assert(!res->empty()); assert(!res->empty());
@ -1521,7 +1684,7 @@ namespace spot
{ {
case multop::And: case multop::And:
{ {
// Gather all operand by type. // Gather all operands by type.
mospliter s(mospliter::Strip_X | mospliter s(mospliter::Strip_X |
mospliter::Strip_FG | mospliter::Strip_FG |
mospliter::Strip_G | mospliter::Strip_G |

21
src/ltlvisit/simplify.hh
View file

@ -31,15 +31,20 @@ namespace spot
class ltl_simplifier_options class ltl_simplifier_options
{ {
public: public:
ltl_simplifier_options() ltl_simplifier_options(bool basics = true,
: reduce_basics(true), bool synt_impl = true,
synt_impl(true), bool event_univ = true,
event_univ(true), bool containment_checks = false,
containment_checks(false), bool containment_checks_stronger = false,
containment_checks_stronger(false), bool nenoform_stop_on_boolean = false)
: reduce_basics(basics),
synt_impl(synt_impl),
event_univ(event_univ),
containment_checks(containment_checks),
containment_checks_stronger(containment_checks_stronger),
// If true, Boolean subformulae will not be put into // If true, Boolean subformulae will not be put into
// negative normal form. // negative normal form.
nenoform_stop_on_boolean(false) nenoform_stop_on_boolean(nenoform_stop_on_boolean)
{ {
} }
@ -48,6 +53,8 @@ namespace spot
bool event_univ; bool event_univ;
bool containment_checks; bool containment_checks;
bool containment_checks_stronger; bool containment_checks_stronger;
// If true, Boolean subformulae will not be put into
// negative normal form.
bool nenoform_stop_on_boolean; bool nenoform_stop_on_boolean;
}; };