Boogie:

* Set Z3's QI_COST as the sum of "weight" and "generation", not their product.  This worked better when setting the :weight of a quantifier (see below).

Dafny:
* Improved axiomatization of sequences; in particular, use an axiom to generate terms that say what the two pieces of a concatenation are
* Two of the (previous) sequence axioms could cause a matching loop, in cases where Z3's arithmetic reasoning does not infer all rational arithmetic equalities during instantiation.  The effect of this was apparently not noticed before, perhaps the concatenation/drop properties previously had to be supplied in manual assert statements.  But now, with the improved sequence axiomatization (see previous bullet), this effect became remarkably noticeable.  To reduce the bad effect of this apparent matching loop, Michal and I added a :weight annotation on two of the axioms, which, along with the Boogie change above, seems to give acceptable results.
* Removed several assert lemmas that are no longer needed in Test programs (the test programs now contain only about a handful of such lemmas)

1 files changed, 7 insertions, 2 deletions

diff --git a/Binaries/DafnyPrelude.bpl b/Binaries/DafnyPrelude.bpl
index 520f9c77..eeb4f103 100644
--- a/Binaries/DafnyPrelude.bpl
+++ b/Binaries/DafnyPrelude.bpl
@@ -153,7 +153,7 @@ axiom (forall<T> s: Seq T, n: int :: { Seq#Length(Seq#Take(s,n)) }
   0 <= n ==>

     (n <= Seq#Length(s) ==> Seq#Length(Seq#Take(s,n)) == n) &&

     (Seq#Length(s) < n ==> Seq#Length(Seq#Take(s,n)) == Seq#Length(s)));

-axiom (forall<T> s: Seq T, n: int, j: int :: { Seq#Index(Seq#Take(s,n), j) }

+axiom (forall<T> s: Seq T, n: int, j: int :: { Seq#Index(Seq#Take(s,n), j) } {:weight 25}

   0 <= j && j < n && j < Seq#Length(s) ==>

     Seq#Index(Seq#Take(s,n), j) == Seq#Index(s, j));

 

@@ -162,10 +162,15 @@ axiom (forall<T> s: Seq T, n: int :: { Seq#Length(Seq#Drop(s,n)) }
   0 <= n ==>

     (n <= Seq#Length(s) ==> Seq#Length(Seq#Drop(s,n)) == Seq#Length(s) - n) &&

     (Seq#Length(s) < n ==> Seq#Length(Seq#Drop(s,n)) == 0));

-axiom (forall<T> s: Seq T, n: int, j: int :: { Seq#Index(Seq#Drop(s,n), j) }

+axiom (forall<T> s: Seq T, n: int, j: int :: { Seq#Index(Seq#Drop(s,n), j) } {:weight 25}

   0 <= n && 0 <= j && j < Seq#Length(s)-n ==>

     Seq#Index(Seq#Drop(s,n), j) == Seq#Index(s, j+n));

 

+axiom (forall<T> s, t: Seq T ::

+  { Seq#Append(s, t) }

+  Seq#Take(Seq#Append(s, t), Seq#Length(s)) == s &&

+  Seq#Drop(Seq#Append(s, t), Seq#Length(s)) == t);

+

 // ---------------------------------------------------------------

 // -- If then else -----------------------------------------------

 // ---------------------------------------------------------------