genltl: add --gf-implies

* spot/gen/formulas.cc, spot/gen/formulas.hh: Implement
LTL_GF_IMPLIES.
* bin/genltl.cc: Add --gf-implies.
* NEWS: Mention it.
* tests/core/genltl.test: Use it.

NEWS

@@ -10,9 +10,10 @@ New in spot 2.4.4.dev (net yet released)
 
   Tools:
 
-  - genltl learned to generate a new family of formulas, taken from
+  - genltl learned to generate two new family of formulas, taken from
     the SYNTCOMP competition on reactive synthesis:
-    --gf-equiv=RANGE      (GFa{1} & GFa{2} & ... & GFa{n}) <-> GFz
+    --gf-equiv=RANGE       (GFa1 & GFa2 & ... & GFan) <-> GFz
+    --gf-implies=RANGE     (GFa1 & GFa2 & ... & GFan) -> GFz
 
   - genltl learned to generate 4 new families of formulas, taken
     from Müller & Sickert's GandALF'17 paper:

bin/genltl.cc

@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2012, 2013, 2015-2017 Laboratoire de Recherche et
+// Copyright (C) 2012, 2013, 2015-2018 Laboratoire de Recherche et
 // Développement de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -88,6 +88,8 @@ static const argp_option options[] =
       "F(p0 | XG(p1 | XG(p2 | ... XG(pn))))", 0},
     { "gf-equiv", gen::LTL_GF_EQUIV, "RANGE", 0,
       "(GFa1 & GFa2 & ... & GFan) <-> GFz", 0},
+    { "gf-implies", gen::LTL_GF_IMPLIES, "RANGE", 0,
+      "(GFa1 & GFa2 & ... & GFan) -> GFz", 0},
     { "gh-q", gen::LTL_GH_Q, "RANGE", 0,
       "(F(p1)|G(p2))&(F(p2)|G(p3))&...&(F(pn)|G(p{n+1}))", 0 },
     { "gh-r", gen::LTL_GH_R, "RANGE", 0,

spot/gen/formulas.cc

@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2012-2017 Laboratoire de Recherche et Developpement
+// Copyright (C) 2012-2018 Laboratoire de Recherche et Developpement
 // de l'EPITA (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -41,18 +41,6 @@ namespace spot
   {
     namespace
     {
-      static formula
-      LTL_GF_equiv(int n, const std::string& a, const std::string& z)
-      {
-        std::vector<formula> gfs;
-        for (int i = 0; i < n; ++i)
-          gfs.emplace_back(formula::G(formula::F(
-                  formula::ap(a + std::to_string(i+1)))));
-
-        return formula::Equiv(formula::And(gfs),
-                              formula::G(formula::F(formula::ap(z))));
-      }
-
       static formula
       ms_example(const char* a, const char* b, int n)
       {
@@ -272,6 +260,18 @@ namespace spot
         return result;
       }
 
+      static formula
+      LTL_GF_equiv_implies(int n, const std::string& a, const std::string& z,
+                           bool equiv)
+      {
+        formula left = GF_n(a, n);
+        formula right = formula::G(formula::F(formula::ap(z)));
+        if (equiv)
+          return formula::Equiv(left, right);
+        else
+          return formula::Implies(left, right);
+      }
+
       //  (((p1 OP p2) OP p3)...OP pn)   if right_assoc == false
       //  (p1 OP (p2 OP (p3 OP (... pn)  if right_assoc == true
       static formula
@@ -1172,7 +1172,9 @@ namespace spot
         case LTL_FXG_OR:
           return FXG_or_n("p", n);
         case LTL_GF_EQUIV:
-          return LTL_GF_equiv(n, "a", "z");
+          return LTL_GF_equiv_implies(n, "a", "z", true);
+        case LTL_GF_IMPLIES:
+          return LTL_GF_equiv_implies(n, "a", "z", false);
         case LTL_GH_Q:
           return Q_n("p", n);
         case LTL_GH_R:
@@ -1254,6 +1256,7 @@ namespace spot
           "eh-patterns",
           "fxg-or",
           "gf-equiv",
+          "gf-implies",
           "gh-q",
           "gh-r",
           "go-theta",
@@ -1312,6 +1315,7 @@ namespace spot
           return 12;
         case LTL_FXG_OR:
         case LTL_GF_EQUIV:
+        case LTL_GF_IMPLIES:
         case LTL_GH_Q:
         case LTL_GH_R:
         case LTL_GO_THETA:

spot/gen/formulas.hh

@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2017 Laboratoire de Recherche et Developpement de
+// Copyright (C) 2017, 2018 Laboratoire de Recherche et Developpement de
 // l'EPITA (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -191,6 +191,7 @@ namespace spot
       LTL_EH_PATTERNS,
       LTL_FXG_OR,
       LTL_GF_EQUIV,
+      LTL_GF_IMPLIES,
       LTL_GH_Q,
       LTL_GH_R,
       LTL_GO_THETA,

tests/core/genltl.test

@@ -1,6 +1,6 @@
 #!/bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2016, 2017 Laboratoire de Recherche et Développement
+# Copyright (C) 2016-2018 Laboratoire de Recherche et Développement
 # de l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
@@ -136,7 +136,7 @@ test $(genltl --kr-nlogn=4 | ltl2tgba --low --stats=%s) -ge 16
 test $(genltl --kr-n=4 | ltl2tgba --low --stats=%s) -ge 16
 
 genltl --ms-example=0..4 --ms-phi-r=0..2 --ms-phi-s=0..2 --ms-phi-h=0..4 \
-       --gf-equiv=0..5 --format=%F=%L,%f |
+       --gf-equiv=0..5 --gf-implies=0..5 --format=%F=%L,%f |
     ltl2tgba -G -D -F-/2 --stats='%<,%s' > out
 cat >exp<<EOF
 ms-example=0,1
@@ -161,11 +161,17 @@ gf-equiv=2,8
 gf-equiv=3,21
 gf-equiv=4,81
 gf-equiv=5,431
+gf-implies=0,1
+gf-implies=1,5
+gf-implies=2,12
+gf-implies=3,41
+gf-implies=4,186
+gf-implies=5,1047
 EOF
 diff out exp
 
 # Running ltl2tgba on one formula at a time should give the same results
 genltl --ms-example=0..4 --ms-phi-r=0..2 --ms-phi-s=0..2 --ms-phi-h=0..4 \
-       --gf-equiv=0..5 --format=%F=%L,%f |
+       --gf-equiv=0..5 --gf-implies=0..5 --format=%F=%L,%f |
     ltldo -F-/2 'ltl2tgba -G -D' --stats='%<,%s' > out
 diff out exp