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merge ltlvisit/ ltlast/ ltlenv/ into a single tl/ directory

Browse source 
The ltl prefix does not make a lot of sens anymore (since we
support psl as well).  ltlast/ and ltlenv/ were almost empty.
And ltlvisit/ did not contain any visitor anymore.

* src/ltlvisit/, src/ltlast/, src/ltlenv/: Merge into...
* src/tl/: ...this.
* NEWS: Mention the change.
* README, bench/stutter/stutter_invariance_formulas.cc,
bench/stutter/stutter_invariance_randomgraph.cc, configure.ac,
doc/org/tut01.org, doc/org/tut02.org, doc/org/tut10.org, doc/tl/tl.tex,
iface/ltsmin/ltsmin.hh, iface/ltsmin/modelcheck.cc, src/Makefile.am,
src/bin/autfilt.cc, src/bin/common_output.cc, src/bin/common_output.hh,
src/bin/common_r.hh, src/bin/common_trans.cc, src/bin/genltl.cc,
src/bin/ltl2tgba.cc, src/bin/ltl2tgta.cc, src/bin/ltlcross.cc,
src/bin/ltldo.cc, src/bin/ltlfilt.cc, src/bin/ltlgrind.cc,
src/bin/randltl.cc, src/kripke/kripkeexplicit.hh,
src/kripkeparse/public.hh, src/parseaut/public.hh, src/priv/accmap.hh,
src/ta/taexplicit.hh, src/ta/tgtaexplicit.hh, src/tests/equalsf.cc,
src/tests/ikwiad.cc, src/tests/length.cc, src/tests/ltlrel.cc,
src/tests/randtgba.cc, src/tests/readltl.cc, src/tests/reduc.cc,
src/tests/syntimpl.cc, src/tests/taatgba.cc, src/tests/tostring.cc,
src/tests/twagraph.cc, src/twa/acc.hh, src/twa/bdddict.cc,
src/twa/bdddict.hh, src/twa/bddprint.cc, src/twa/taatgba.cc,
src/twa/taatgba.hh, src/twa/twa.hh, src/twa/twagraph.cc,
src/twa/twagraph.hh, src/twa/twasafracomplement.cc,
src/twaalgos/compsusp.cc, src/twaalgos/compsusp.hh,
src/twaalgos/dtgbasat.cc, src/twaalgos/hoa.cc,
src/twaalgos/isweakscc.cc, src/twaalgos/lbtt.cc,
src/twaalgos/ltl2taa.cc, src/twaalgos/ltl2taa.hh,
src/twaalgos/ltl2tgba_fm.cc, src/twaalgos/ltl2tgba_fm.hh,
src/twaalgos/minimize.hh, src/twaalgos/neverclaim.cc,
src/twaalgos/randomgraph.hh, src/twaalgos/relabel.hh,
src/twaalgos/remprop.hh, src/twaalgos/stats.cc, src/twaalgos/stutter.cc,
src/twaalgos/translate.hh, wrap/python/spot_impl.i,
src/ltlparse/ltlparse.yy, src/ltlparse/public.hh: Adjust.
This commit is contained in:
Alexandre Duret-Lutz 2015-09-28 15:15:55 +02:00
parent 3e10dba978
commit 6ded5e75c4
119 changed files with 269 additions and 343 deletions
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src/tl/relabel.cc Normal file
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// -*- coding: utf-8 -*-
// Copyright (C) 2012, 2013, 2014, 2015 Laboratoire de Recherche et
// Développement de l'Epita (LRDE).
//
// This file is part of Spot, a model checking library.
//
// Spot is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// Spot is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
// License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "relabel.hh"
#include <sstream>
#include "misc/hash.hh"
#include <map>
#include <set>
#include <stack>
#include <iostream>
namespace spot
{
namespace ltl
{
//////////////////////////////////////////////////////////////////////
// Basic relabeler
//////////////////////////////////////////////////////////////////////
namespace
{
struct ap_generator
{
virtual formula next() = 0;
virtual ~ap_generator() {}
};
struct pnn_generator final: ap_generator
{
unsigned nn;
pnn_generator()
: nn(0)
{
}
formula next()
{
std::ostringstream s;
s << 'p' << nn++;
return formula::ap(s.str());
}
};
struct abc_generator final: ap_generator
{
public:
abc_generator()
: nn(0)
{
}
unsigned nn;
formula next()
{
std::string s;
unsigned n = nn++;
do
{
s.push_back('a' + (n % 26));
n /= 26;
}
while (n);
return formula::ap(s);
}
};
class relabeler
{
public:
typedef std::unordered_map<formula, formula> map;
map newname;
ap_generator* gen;
relabeling_map* oldnames;
relabeler(ap_generator* gen, relabeling_map* m)
: gen(gen), oldnames(m)
{
}
~relabeler()
{
delete gen;
}
formula rename(formula old)
{
auto r = newname.emplace(old, nullptr);
if (!r.second)
{
return r.first->second;
}
else
{
formula res = gen->next();
r.first->second = res;
if (oldnames)
(*oldnames)[res] = old;
return res;
}
}
formula
visit(formula f)
{
if (f.is(op::ap))
return rename(f);
else
return f.map([this](formula f)
{
return this->visit(f);
});
}
};
}
formula
relabel(formula f, relabeling_style style, relabeling_map* m)
{
ap_generator* gen = nullptr;
switch (style)
{
case Pnn:
gen = new pnn_generator;
break;
case Abc:
gen = new abc_generator;
break;
}
relabeler r(gen, m);
return r.visit(f);
}
//////////////////////////////////////////////////////////////////////
// Boolean-subexpression relabeler
//////////////////////////////////////////////////////////////////////
// Here we want to rewrite a formula such as
// "a & b & X(c & d) & GF(c & d)" into "p0 & Xp1 & GFp1"
// where Boolean subexpressions are replaced by fresh propositions.
//
// Detecting Boolean subexpressions is not a problem.
// Furthermore, because we are already representing LTL formulas
// with sharing of identical sub-expressions we can easily rename
// a subexpression (such as c&d above) only once. However this
// scheme has two problems:
//
// 1. It will not detect inter-dependent Boolean subexpressions.
// For instance it will mistakenly relabel "(a & b) U (a & !b)"
// as "p0 U p1", hiding the dependency between a&b and a&!b.
//
// 2. Because of our n-ary operators, it will fail to
// notice that (a & b) is a sub-expression of (a & b & c).
//
// The code below only addresses point 1 so that interdependent
// subexpressions are not relabeled. Point 2 could be improved in
// a future version of somebody feels inclined to do so.
//
// The way we compute the subexpressions that can be relabeled is
// by transforming the formula syntax tree into an undirected
// graph, and computing the cut points of this graph. The cut
// points (or articulation points) are the nodes whose removal
// would split the graph in two components. To ensure that a
// Boolean operator is only considered as a cut point if it would
// separate all of its children from the rest of the graph, we
// connect all the children of Boolean operators.
//
// For instance (a & b) U (c & d) has two (Boolean) cut points
// corresponding to the two AND operators:
//
// (a&b)U(c&d)
// ╱ ╲
// a&b c&d
// ╱ ╲ ╱ ╲
// a─────b c─────d
//
// (The root node is also a cut-point, but we only consider Boolean
// cut-points for relabeling.)
//
// On the other hand, (a & b) U (b & !c) has only one Boolean
// cut-point which corresponds to the NOT operator:
//
// (a&b)U(b&!c)
// ╱ ╲
// a&b b&c
// ╱ ╲ ╱ ╲
// a─────b────!c
// │
// c
//
// Note that if the children of a&b and b&c were not connected,
// a&b and b&c would be considered as cut points because they
// separate "a" or "!c" from the rest of the graph.
//
// The relabeling of a formula is therefore done in 3 passes:
// 1. convert the formula's syntax tree into an undirected graph,
// adding links between children of Boolean operators
// 2. compute the (Boolean) cut points of that graph, using the
// Hopcroft-Tarjan algorithm (see below for a reference)
// 3. recursively scan the formula's tree until we reach
// either a (Boolean) cut point or an atomic proposition, and
// replace that node by a fresh atomic proposition.
//
// In the example above (a&b)U(b&!c), the last recursion
// stop a, b, and !c, producing (p0&p1)U(p1&p2).
namespace
{
typedef std::vector<formula> succ_vec;
typedef std::map<formula, succ_vec> fgraph;
// Convert the formula's syntax tree into an undirected graph
// labeled by subformulas.
class formula_to_fgraph final
{
public:
fgraph& g;
std::stack<formula> s;
formula_to_fgraph(fgraph& g):
g(g)
{
}
~formula_to_fgraph()
{
}
void
visit(formula f)
{
{
// Connect to parent
auto in = g.emplace(f, succ_vec());
if (!s.empty())
{
formula top = s.top();
in.first->second.push_back(top);
g[top].push_back(f);
if (!in.second)
return;
}
else
{
assert(in.second);
}
}
s.push(f);
unsigned sz = f.size();
unsigned i = 0;
if (sz > 2 && !f.is_boolean())
{
/// If we have a formula like (a & b & Xc), consider
/// it as ((a & b) & Xc) in the graph to isolate the
/// Boolean operands as a single node.
formula b = f.boolean_operands(&i);
if (b)
visit(b);
}
for (; i < sz; ++i)
visit(f[i]);
if (sz > 1 && f.is_boolean())
{
// For Boolean nodes, connect all children in a
// loop. This way the node can only be a cut-point
// if it separates all children from the reset of
// the graph (not only one).
formula pred = f[0];
for (i = 1; i < sz; ++i)
{
formula next = f[i];
// Note that we only add an edge in one
// direction, because we are building a cycle
// between all children anyway.
g[pred].push_back(next);
pred = next;
}
g[pred].push_back(f[0]);
}
s.pop();
}
};
typedef std::set<formula> fset;
struct data_entry // for each node of the graph
{
unsigned num; // serial number, in pre-order
unsigned low; // lowest number accessible via unstacked descendants
data_entry(unsigned num = 0, unsigned low = 0)
: num(num), low(low)
{
}
};
typedef std::unordered_map<formula, data_entry> fmap_t;
struct stack_entry
{
formula grand_parent;
formula parent; // current node
succ_vec::const_iterator current_child;
succ_vec::const_iterator last_child;
};
typedef std::stack<stack_entry> stack_t;
// Fill c with the Boolean cutpoints of g, starting from start.
//
// This is based no "Efficient Algorithms for Graph
// Manipulation", J. Hopcroft & R. Tarjan, in Communications of
// the ACM, 16 (6), June 1973.
//
// It differs from the original algorithm by returning only the
// Boolean cutpoints, and not dealing with the initial state
// properly (our initial state will always be considered as a
// cut-point, but since we only return Boolean cut-points it's
// OK: if the top-most formula is Boolean we want to replace it
// as a whole).
void cut_points(const fgraph& g, fset& c, formula start)
{
stack_t s;
unsigned num = 0;
fmap_t data;
data_entry d = { num, num };
data[start] = d;
++num;
const succ_vec& children = g.find(start)->second;
stack_entry e = { start, start, children.begin(), children.end() };
s.push(e);
while (!s.empty())
{
stack_entry& e = s.top();
if (e.current_child != e.last_child)
{
// Skip the edge if it is just the reverse of the one
// we took.
formula child = *e.current_child;
if (child == e.grand_parent)
{
++e.current_child;
continue;
}
auto i = data.emplace(std::piecewise_construct,
std::forward_as_tuple(child),
std::forward_as_tuple(num, num));
if (i.second) // New destination.
{
++num;
const succ_vec& children = g.find(child)->second;
stack_entry newe = { e.parent, child,
children.begin(), children.end() };
s.push(newe);
}
else // Destination exists.
{
data_entry& dparent = data[e.parent];
data_entry& dchild = i.first->second;
// If this is a back-edge, update
// the low field of the parent.
if (dchild.num <= dparent.num)
if (dparent.low > dchild.num)
dparent.low = dchild.num;
}
++e.current_child;
}
else
{
formula grand_parent = e.grand_parent;
formula parent = e.parent;
s.pop();
if (!s.empty())
{
data_entry& dparent = data[parent];
data_entry& dgrand_parent = data[grand_parent];
if (dparent.low >= dgrand_parent.num // cut-point
&& grand_parent.is_boolean())
c.insert(grand_parent);
if (dparent.low < dgrand_parent.low)
dgrand_parent.low = dparent.low;
}
}
}
}
class bse_relabeler final: public relabeler
{
public:
fset& c;
bse_relabeler(ap_generator* gen, fset& c,
relabeling_map* m)
: relabeler(gen, m), c(c)
{
}
using relabeler::visit;
formula
visit(formula f)
{
if (f.is(op::ap) || (c.find(f) != c.end()))
return rename(f);
unsigned sz = f.size();
if (sz <= 2)
return f.map([this](formula f)
{
return visit(f);
});
unsigned i = 0;
std::vector<formula> res;
/// If we have a formula like (a & b & Xc), consider
/// it as ((a & b) & Xc) in the graph to isolate the
/// Boolean operands as a single node.
formula b = f.boolean_operands(&i);
if (b)
{
res.reserve(sz - i + 1);
res.push_back(visit(b));
}
else
{
res.reserve(sz);
}
for (; i < sz; ++i)
res.push_back(visit(f[i]));
return formula::multop(f.kind(), res);
}
};
}
formula
relabel_bse(formula f, relabeling_style style, relabeling_map* m)
{
fgraph g;
// Build the graph g from the formula f.
{
formula_to_fgraph conv(g);
conv.visit(f);
}
// Compute its cut-points
fset c;
cut_points(g, c, f);
// Relabel the formula recursively, stopping
// at cut-points or atomic propositions.
ap_generator* gen = nullptr;
switch (style)
{
case Pnn:
gen = new pnn_generator;
break;
case Abc:
gen = new abc_generator;
break;
}
bse_relabeler rel(gen, c, m);
return rel.visit(f);
}
}
}