From f6ba7be1733d99eb767bb38b30533ac70e179676 Mon Sep 17 00:00:00 2001
From: Neil Brown <neil@twistedsquare.com>
Date: Tue, 15 Jan 2008 17:33:19 +0000
Subject: [PATCH] Changed various uses of the maximum function to make sure
 they always succeed

---
 transformations/ArrayUsageCheck.hs     | 4 ++--
 transformations/ArrayUsageCheckTest.hs | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/transformations/ArrayUsageCheck.hs b/transformations/ArrayUsageCheck.hs
index a302b12..5b50090 100644
--- a/transformations/ArrayUsageCheck.hs
+++ b/transformations/ArrayUsageCheck.hs
@@ -357,7 +357,7 @@ makeEquations es high = makeEquations' >>* (\(s,v,lh) -> [(s,squareEquations eqI
     mapToArray :: (IArray a v, Num v, Num k, Ord k, Ix k) => Map.Map k v -> a k v
     mapToArray m = accumArray (+) 0 (0, highest') . Map.assocs $ m
       where
-        highest' = maximum $ Map.keys m
+        highest' = maximum $ 0 : Map.keys m
     
     -- | Given a pair of equation sets, makes all the equations in the lists be the length
     -- of the longest equation.  All missing elements are of course given value zero.
@@ -368,7 +368,7 @@ makeEquations es high = makeEquations' >>* (\(s,v,lh) -> [(s,squareEquations eqI
         makeSize :: (Show i, Show e,IArray a e, Ix i, Enum i) => (i,i) -> e -> a i e -> a i e
         makeSize size def arr = array size [(i,arrayLookupWithDefault def arr i) | i <- [fst size .. snd size]]
       
-        highest = maximum $ concatMap indices $ eqs ++ ineqs
+        highest = maximum $ 0 : (concatMap indices $ eqs ++ ineqs)
     
 type CoeffIndex = Int
 type EqualityConstraintEquation = Array CoeffIndex Integer
diff --git a/transformations/ArrayUsageCheckTest.hs b/transformations/ArrayUsageCheckTest.hs
index 4fb5cf2..c4ee671 100644
--- a/transformations/ArrayUsageCheckTest.hs
+++ b/transformations/ArrayUsageCheckTest.hs
@@ -175,7 +175,7 @@ makeConsistent eqs ineqs = (map ensure eqs', map ensure ineqs')
     ineqs' = map (\(Ineq e) -> e) ineqs
       
     ensure = accumArray (+) 0 (0, largestIndex)
-    largestIndex = maximum $ map (maximum . map fst) $ eqs' ++ ineqs'
+    largestIndex = maximum $ map (maximum . map fst) $ [[(0,0)]] ++ eqs' ++ ineqs'
 
 
 -- | Returns Nothing if there is definitely no solution, or (Just ineq) if