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simplify: rewrite GF(a & GFb) as G(Fa & Fb)

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Fixes #185.

* spot/tl/simplify.cc: Implement the new rule.
* NEWS, doc/tl/tl.tex: Document it.
* tests/core/reduccmp.test: Test it.
This commit is contained in:
Alexandre Duret-Lutz 2016-09-22 17:37:55 +02:00
parent 01d84c4d52
commit 6528d75339
4 changed files with 30 additions and 0 deletions
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8
NEWS
View file

@ -1,5 +1,13 @@
New in spot 2.1.1a (not yet released)
Library:
* New LTL simplification rule:
- GF(f & q) = G(F(f) & q) if q is
purely universal and a pure eventuality. In particular
GF(f & GF(g)) now ultimately simplifies to G(F(f) & F(g)).
Bug fixes:
- Fix spurious uninitialized read reported by valgrind when

1
doc/tl/tl.tex
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@ -1690,6 +1690,7 @@ $q,\,q_i$ & a pure eventuality that is also purely universal \\
\G(f_1\OR\ldots\OR f_n \OR q_1 \OR \ldots \OR q_p)&\equiv \G(f_1\OR\ldots\OR f_n)\OR q_1 \OR \ldots \OR q_p \\
\F(f_1\AND\ldots\AND f_n \AND q_1 \AND \ldots \AND q_p)&\equivEU \F(f_1\AND\ldots\AND f_n)\AND q_1 \AND \ldots \AND q_p \\
\G(f_1\AND\ldots\AND f_n \AND q_1 \AND \ldots \AND q_p)&\equivEU \G(f_1\AND\ldots\AND f_n)\AND q_1 \AND \ldots \AND q_p \\
\G\F(f_1\AND\ldots\AND f_n \AND q_1 \AND \ldots \AND q_p)&\equiv \G(\F(f_1\AND\ldots\AND f_n)\AND q_1 \AND \ldots \AND q_p) \\
\G(f_1\AND\ldots\AND f_n \AND e_1 \AND \ldots \AND e_m \AND \G(e_{m+1}) \AND \ldots\AND \G(e_p))&\equivEU \G(f_1\AND\ldots\AND f_n)\AND \G(e_1 \AND \ldots \AND e_p) \\
\G(f_1\AND\ldots\AND f_n \AND \G(g_1) \AND \ldots \AND \G(g_m) &\equiv \G(f_1\AND\ldots\AND f_n\AND g_1 \AND \ldots \AND g_m) \\
\F(f_1 \OR \ldots \OR f_n \OR u_1 \OR \ldots \OR u_m \OR \F(u_{m+1})\OR\ldots\OR \F(u_p)) &\equivEU \F(f_1\OR \ldots\OR f_n) \OR \F(u_1 \OR \ldots \OR u_p)\\

19
spot/tl/simplify.cc
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@ -968,6 +968,12 @@ namespace spot
// So we do not consider this rewriting rule by
// default. However if favor_event_univ is set,
// we want to move the GF out of the F.
//
// Also if this appears inside a G, we want to
// reduce it:
// GF(f1 & GF(f2)) = G(F(f1) & GF(f2))
// = G(F(f1) & F(f2))
// But this is handled by the G case.
if (opt_.favor_event_univ)
// F(f1&f2&FG(f3)&FG(f4)&f5&f6) =
// F(f1&f2) & FG(f3&f4) & f5 & f6
@ -1114,6 +1120,19 @@ namespace spot
return recurse(unop_unop(op::G, op::F, out));
}
}
// GF(f1 & f2 & eu1 & eu2) = G(F(f1 & f2) & eu1 & eu2
if (opt_.event_univ && c.is({op::F, op::And}))
{
mospliter s(mospliter::Split_EventUniv,
c[0], c_);
s.res_EventUniv->
push_back(unop_multop(op::F, op::And,
std::move(*s.res_other)));
formula res =
formula::G(formula::And(std::move(*s.res_EventUniv)));
if (res != f)
return recurse(res);
}
}
// if a => Ga, keep a.
if (opt_.containment_checks_stronger

2
tests/core/reduccmp.test
View file

@ -403,6 +403,8 @@ G(GFc|GFd|FGe|FGf), F(GF(c|d)|Ge|Gf)
{e[*0..5]}<>->f, {e[*1..5]}<>->f
{e[*0..5]}[]->f, {e[*1..5]}[]->f
{(e+[*0])[*0..5]}[]->f, {e[*1..5]}[]->f
# issue 185
GF(a && GF(b) && c), G(F(a & c) & Fb)
# not reduced
{a;(b[*2..4];c*;([*0]+{d;e}))*}!, {a;(b[*2..4];c*;([*0]+{d;e}))*}!
{c[*];e[*]}[]-> a, {c[*];e[*]}[]-> a