Merges branches/arithmetic/atom-database r2979 through 3247 into trunk. Below is a highlight of the changes:

- This introduces a new normal form to arithmetic.
-- Equalities and disequalities are in solved form.
   Roughly speaking this means: (= x (+ y z)) is in normal form.
   (See the comments in normal_form.h for what this formally requires.)
-- The normal form for inequality atoms always uses GEQ and GT instead of GEQ and LEQ.
   Integer atoms always use GEQ.
- Constraint was added to TheoryArith.
-- A constraint is a triple of (k x v) where:
--- k is the type of the constraint (either LowerBound, UpperBound, Equality or Disequality),
--- x is an ArithVar, and
--- v is a DeltaRational value.
-- Constraints are always attached to a ConstraintDatabase.
-- A Constraint has its negation in the ConstraintDatabase [at least for now].
-- Every constraint belongs to a set of constraints for each ArithVar sorted by the delta rational values.
-- This set can be iterated over and provides efficient access to other constraints for this variable.
-- A literal may be attached to a constraint.
-- Constraints with attached literals may be marked as being asserted to the theory (sat context dependent).
-- Constraints can be propagated.
-- Every constraint has a proof (sat context dependent).
-- Proofs can be explained for either conflicts or propagations (if the node was propagated). (These proofs may be different.)
-- Equalities and disequalities can be marked as being split (user context dependent)
- This removes and replaces:
-- src/theory/arith/arith_prop_manager.*
-- src/theory/arith/atom_database.*
-- src/theory/arith/ordered_set.h
- Added isZero(), isOne() and isNegativeOne() to Rational and Integer.
- Added operator+ to CDList::const_iterator.
- Added const_iterator to CDQueue.
- Changes to regression tests.

6 files changed, 57 insertions, 3 deletions

diff --git a/src/util/integer_cln_imp.h b/src/util/integer_cln_imp.h
index 9d67e8fba..d3e5c07ca 100644
--- a/src/util/integer_cln_imp.h
+++ b/src/util/integer_cln_imp.h
@@ -366,6 +366,18 @@ public:
     return cln::cl_I_to_int(sgn);
   }
 
+  bool isZero() const {
+    return cln::zerop(d_value);
+  }
+
+  bool isOne() const {
+    return d_value == 1;
+  }
+
+  bool isNegativeOne() const {
+    return d_value == -1;
+  }
+
   //friend std::ostream& operator<<(std::ostream& os, const Integer& n);
 
   long getLong() const {
diff --git a/src/util/integer_gmp_imp.h b/src/util/integer_gmp_imp.h
index ceb585852..74b4adad0 100644
--- a/src/util/integer_gmp_imp.h
+++ b/src/util/integer_gmp_imp.h
@@ -276,6 +276,18 @@ public:
     return mpz_sgn(d_value.get_mpz_t());
   }
 
+  bool isZero() const {
+    return sgn() == 0;
+  }
+
+  bool isOne() const {
+    return mpz_cmp_si(d_value.get_mpz_t(), 1) == 0;
+  }
+
+  bool isNegativeOne() const {
+    return mpz_cmp_si(d_value.get_mpz_t(), -1) == 0;
+  }
+
   /**
    * Raise this Integer to the power <code>exp</code>.
    *
diff --git a/src/util/options.cpp b/src/util/options.cpp
index b6956a31b..b6a306ee0 100644
--- a/src/util/options.cpp
+++ b/src/util/options.cpp
@@ -110,6 +110,7 @@ Options::Options() :
   ufSymmetryBreaker(false),
   ufSymmetryBreakerSetByUser(false),
   dioSolver(true),
+  arithRewriteEq(true),
   lemmaOutputChannel(NULL),
   lemmaInputChannel(NULL),
   threads(2),// default should be 1 probably, but say 2 for now
@@ -183,6 +184,7 @@ Additional CVC4 options:\n\
    --enable-symmetry-breaker turns on UF symmetry breaker (Deharbe et al., CADE 2011) [on by default only for QF_UF]\n\
    --disable-symmetry-breaker turns off UF symmetry breaker\n\
    --disable-dio-solver   turns off Linear Diophantine Equation solver (Griggio, JSAT 2012)\n\
+   --disable-arith-rewrite-equalities   turns off the preprocessing rewrite turning equalities into a conjunction of inequalities.\n \
    --threads=N            sets the number of solver threads\n\
    --threadN=string       configures thread N (0..#threads-1)\n\
    --filter-lemma-length=N don't share lemmas strictly longer than N\n\
@@ -356,6 +358,7 @@ enum OptionValue {
   ARITHMETIC_PIVOT_THRESHOLD,
   ARITHMETIC_PROP_MAX_LENGTH,
   ARITHMETIC_DIO_SOLVER,
+  ARITHMETIC_REWRITE_EQUALITIES,
   ENABLE_SYMMETRY_BREAKER,
   DISABLE_SYMMETRY_BREAKER,
   PARALLEL_THREADS,
@@ -445,6 +448,7 @@ static struct option cmdlineOptions[] = {
   { "print-winner", no_argument     , NULL, PRINT_WINNER  },
   { "disable-arithmetic-propagation", no_argument, NULL, ARITHMETIC_PROPAGATION },
   { "disable-dio-solver", no_argument, NULL, ARITHMETIC_DIO_SOLVER },
+  { "disable-arith-rewrite-equalities", no_argument, NULL, ARITHMETIC_REWRITE_EQUALITIES },
   { "enable-symmetry-breaker", no_argument, NULL, ENABLE_SYMMETRY_BREAKER },
   { "disable-symmetry-breaker", no_argument, NULL, DISABLE_SYMMETRY_BREAKER },
   { "threads", required_argument, NULL, PARALLEL_THREADS },
@@ -796,6 +800,10 @@ throw(OptionException) {
       dioSolver = false;
       break;
 
+    case ARITHMETIC_REWRITE_EQUALITIES:
+      arithRewriteEq = false;
+      break;
+
     case ENABLE_SYMMETRY_BREAKER:
       ufSymmetryBreaker = true;
       ufSymmetryBreakerSetByUser = true;
diff --git a/src/util/options.h b/src/util/options.h
index 4bf8b5b75..c7fbcd896 100644
--- a/src/util/options.h
+++ b/src/util/options.h
@@ -156,7 +156,7 @@ struct CVC4_PUBLIC Options {
 
   /** Whether we produce proofs. */
   bool proof;
-  
+
   /** Whether we support SmtEngine::getAssignment() for this run. */
   bool produceAssignments;
 
@@ -195,7 +195,7 @@ struct CVC4_PUBLIC Options {
 
   /** Variable activity decay factor for Minisat */
   double satVarDecay;
-  
+
   /** Clause activity decay factor for Minisat */
   double satClauseDecay;
 
@@ -238,6 +238,12 @@ struct CVC4_PUBLIC Options {
    */
   bool dioSolver;
 
+  /**
+   * Whether to split (= x y) into (and (<= x y) (>= x y)) in
+   * arithmetic preprocessing.
+   */
+  bool arithRewriteEq;
+
   /** The output channel to receive notfication events for new lemmas */
   LemmaOutputChannel* lemmaOutputChannel;
   LemmaInputChannel* lemmaInputChannel;
@@ -251,7 +257,7 @@ struct CVC4_PUBLIC Options {
   /** Thread ID, for internal use in case of multi-threaded run */
   int thread_id;
 
-  /** 
+  /**
    * In multi-threaded setting print output of each thread at the
    * end of run, separated by a divider ("----").
    **/
diff --git a/src/util/rational_cln_imp.h b/src/util/rational_cln_imp.h
index 69eede0d6..c2da0e7ed 100644
--- a/src/util/rational_cln_imp.h
+++ b/src/util/rational_cln_imp.h
@@ -196,6 +196,14 @@ public:
     return cln::zerop(d_value);
   }
 
+  bool isOne() const {
+    return d_value == 1;
+  }
+
+  bool isNegativeOne() const {
+    return d_value == -1;
+  }
+
   Rational abs() const {
     if(sgn() < 0){
       return -(*this);
diff --git a/src/util/rational_gmp_imp.h b/src/util/rational_gmp_imp.h
index 751c8f137..ef0720263 100644
--- a/src/util/rational_gmp_imp.h
+++ b/src/util/rational_gmp_imp.h
@@ -173,6 +173,14 @@ public:
     return sgn() == 0;
   }
 
+  bool isOne() const {
+    return mpq_cmp_si(d_value.get_mpq_t(), 1, 1) == 0;
+  }
+
+  bool isNegativeOne() const {
+    return mpq_cmp_si(d_value.get_mpq_t(), -1, 1) == 0;
+  }
+
   Rational abs() const {
     if(sgn() < 0){
       return -(*this);