Factor out handling of subtraction

Shimuuar · Aug 30, 2012 · ee4709b · ee4709b
1 parent 02fa0b3
commit ee4709b
Showing 1 changed file with 2 additions and 6 deletions.
diff --git a/Numeric/BLAS/Expression.hs b/Numeric/BLAS/Expression.hs
@@ -193,6 +193,8 @@ evalST :: (() -> Cont s) -> Expr m a -> ST s (Mutable m s a)
 {-# INLINE evalST #-}
 -- Reduce double scale.
 evalST cont (Scale q α (Scale _ β e)) = cont q $ Scale () (α*β) e
+-- Convert subtraction to addition
+evalST cont (Sub _ x (Scale q α y)) = cont q $ Add () x (Scale () (-α) y)
 --
 --   Addition
 --   ========
@@ -209,9 +211,7 @@ evalST cont (Add _  m            (VecH q v u))  | Just m_ <- mutable (cont q) m
 evalST cont (Add _  m (Scale _ α (VecH q v u))) | Just m_ <- mutable (cont q) m = inplaceEvalVVH (cont q)   α  v u =<< m_
 -- NOTE: A ← α·x·y' + A | for subtraction coefficient α must be negated
 evalST cont (Sub _  m            (VecT q v u))  | Just m_ <- mutable (cont q) m = inplaceEvalVVT (cont q) (-1) v u =<< m_
-evalST cont (Sub _  m (Scale _ α (VecT q v u))) | Just m_ <- mutable (cont q) m = inplaceEvalVVT (cont q) (-α) v u =<< m_
 evalST cont (Sub _  m            (VecH q v u))  | Just m_ <- mutable (cont q) m = inplaceEvalVVH (cont q) (-1) v u =<< m_
-evalST cont (Sub _  m (Scale _ α (VecH q v u))) | Just m_ <- mutable (cont q) m = inplaceEvalVVH (cont q) (-α) v u =<< m_
 --
 -- * Matrix x Vector
 evalST cont (Add _            u             (MulMV q m v))  | Just u_ <- mutable (cont q) u = inplaceEvalMV (cont q)   1  m v 1 =<< u_
@@ -221,8 +221,6 @@ evalST cont (Add _ (Scale _ β u) (Scale _ α (MulMV q m v))) | Just u_ <- mutab
 -- NOTE: y ← α·A·x + β·y   | for subtraction coefficient α must be negated
 evalST cont (Sub _            u             (MulMV q m v))  | Just u_ <- mutable (cont q) u = inplaceEvalMV (cont q) (-1) m v 1 =<< u_
 evalST cont (Sub _            u  (Scale _ α (MulMV q m v))) | Just u_ <- mutable (cont q) u = inplaceEvalMV (cont q) (-α) m v 1 =<< u_
-evalST cont (Sub _ (Scale _ β u)            (MulMV q m v))  | Just u_ <- mutable (cont q) u = inplaceEvalMV (cont q) (-1) m v β =<< u_
-evalST cont (Sub _ (Scale _ β u) (Scale _ α (MulMV q m v))) | Just u_ <- mutable (cont q) u = inplaceEvalMV (cont q) (-α) m v β =<< u_
 --
 -- * op(Matrix) x Vector
 evalST cont (Add _            u             (MulTMV q t m v))  | Just u_ <- mutable (cont q) u = inplaceEvalTMV (cont q)   1  t m v 1 =<< u_
@@ -232,8 +230,6 @@ evalST cont (Add _ (Scale _ β u) (Scale _ α (MulTMV q t m v))) | Just u_ <- mu
 -- NOTE: C ← α·op(A)·op(B) + β·C   | for subtraction coefficient α must be negated
 evalST cont (Sub _            u             (MulTMV q t m v))  | Just u_ <- mutable (cont q) u = inplaceEvalTMV (cont q) (-1) t m v 1 =<< u_
 evalST cont (Sub _            u  (Scale _ α (MulTMV q t m v))) | Just u_ <- mutable (cont q) u = inplaceEvalTMV (cont q) (-α) t m v 1 =<< u_
-evalST cont (Sub _ (Scale _ β u)            (MulTMV q t m v))  | Just u_ <- mutable (cont q) u = inplaceEvalTMV (cont q) (-1) t m v β =<< u_
-evalST cont (Sub _ (Scale _ β u) (Scale _ α (MulTMV q t m v))) | Just u_ <- mutable (cont q) u = inplaceEvalTMV (cont q) (-α) t m v β =<< u_
 -- * No nice rules match. We have to use generic function. But still
 --   let try to reuse temporaries as much as possible
 evalST cont (Add q x y)