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.

1 files changed, 8 insertions, 5 deletions

diff --git a/src/theory/arith/linear_equality.h b/src/theory/arith/linear_equality.h
index 4d1d917b3..b5d439769 100644
--- a/src/theory/arith/linear_equality.h
+++ b/src/theory/arith/linear_equality.h
@@ -36,6 +36,7 @@
 #include "theory/arith/arithvar.h"
 #include "theory/arith/partial_model.h"
 #include "theory/arith/tableau.h"
+#include "theory/arith/constraint.h"
 
 #include "util/stats.h"
 
@@ -101,14 +102,16 @@ private:
    * of the basic variable basic, using the non-basic variables in the row.
    */
   template <bool upperBound>
-  void explainNonbasics(ArithVar basic, NodeBuilder<>& output);
+  void propagateNonbasics(ArithVar basic, Constraint c);
 
 public:
-  void explainNonbasicsLowerBound(ArithVar basic, NodeBuilder<>& output){
-    explainNonbasics<false>(basic, output);
+  void propagateNonbasicsLowerBound(ArithVar basic, Constraint c){
+    Assert(c->isLowerBound());
+    propagateNonbasics<false>(basic, c);
   }
-  void explainNonbasicsUpperBound(ArithVar basic, NodeBuilder<>& output){
-    explainNonbasics<true>(basic, output);
+  void propagateNonbasicsUpperBound(ArithVar basic, Constraint c){
+    Assert(c->isUpperBound());
+    propagateNonbasics<true>(basic, c);
   }
 
   /**