Merge from decision branch -- partially working justification heuristic

Overview of changes
* command line option --decision={internal,justification}
* justification heuristic handles all operators except ITEs
  revelant stats: decision::jh::*
* if decisionEngine has solved the problem PropEngine returns
  unknown and smtEngine queries DE to get the answer
  relevant stat: smt::resultSource
* there are known bugs

Full list of commits being merged
r3330 use CD data structures in JH
r3329 add command-line option --decision=MODE
r3328 timer stat, other fixes
r3326 more trace
r3325 enable implies, iff, xor (no further regression losses)
r3324 feed decision engine lemmas, changes to quitting mechanism
r3322 In progress
r3321 more fixes...
r3318 bugfix1 (69 more to go)
r3317 Handle other boolean operators in JH (except ITE)
r3316 mechanism for DE to stopSearch
r3315 merge from trunk + JH translation continuation
r3275 change option to enable JH by default[A

1 files changed, 29 insertions, 0 deletions

diff --git a/src/util/options.cpp b/src/util/options.cpp
index 0bd02f308..4e8bc375b 100644
--- a/src/util/options.cpp
+++ b/src/util/options.cpp
@@ -172,6 +172,7 @@ Additional CVC4 options:\n\
    --print-expr-types     print types with variables when printing exprs\n\
    --lazy-definition-expansion expand define-funs/LAMBDAs lazily\n\
    --simplification=MODE  choose simplification mode, see --simplification=help\n\
+   --decision=MODE        choose decision mode, see --decision=help\n\
    --no-static-learning   turn off static learning (e.g. diamond-breaking)\n\
    --replay=file          replay decisions from file\n\
    --replay-log=file      log decisions and propagations to file\n\
@@ -225,6 +226,16 @@ none\n\
 + do not perform nonclausal simplification\n\
 ";
 
+static const string decisionHelp = "\
+Decision modes currently supported by the --decision option:\n\
+\n\
+internal (default)\n\
++ Use the internal decision hueristics of the SAT solver\n\
+\n\
+justification\n\
++ An ATGP-inspired justification heuristic\n\
+";
+
 static const string dumpHelp = "\
 Dump modes currently supported by the --dump option:\n\
 \n\
@@ -338,6 +349,7 @@ enum OptionValue {
   UF_THEORY,
   LAZY_DEFINITION_EXPANSION,
   SIMPLIFICATION_MODE,
+  DECISION_MODE,
   NO_STATIC_LEARNING,
   INTERACTIVE,
   NO_INTERACTIVE,
@@ -426,6 +438,7 @@ static struct option cmdlineOptions[] = {
   { "uf"         , required_argument, NULL, UF_THEORY   },
   { "lazy-definition-expansion", no_argument, NULL, LAZY_DEFINITION_EXPANSION },
   { "simplification", required_argument, NULL, SIMPLIFICATION_MODE },
+  { "decision", required_argument, NULL, DECISION_MODE },
   { "no-static-learning", no_argument, NULL, NO_STATIC_LEARNING },
   { "interactive", no_argument      , NULL, INTERACTIVE },
   { "no-interactive", no_argument   , NULL, NO_INTERACTIVE },
@@ -696,6 +709,22 @@ throw(OptionException) {
       }
       break;
 
+    case DECISION_MODE:
+      if(!strcmp(optarg, "internal")) {
+        decisionMode = DECISION_STRATEGY_INTERNAL;
+        decisionModeSetByUser = true;
+      } else if(!strcmp(optarg, "justification")) {
+        decisionMode = DECISION_STRATEGY_JUSTIFICATION;
+        decisionModeSetByUser = true;
+      } else if(!strcmp(optarg, "help")) {
+        puts(decisionHelp.c_str());
+        exit(1);
+      } else {
+        throw OptionException(string("unknown option for --decision: `") +
+                              optarg + "'.  Try --decision help.");
+      }
+      break;
+
     case NO_STATIC_LEARNING:
       doStaticLearning = false;
       break;