Working argument accum mode (...)

The derivative of 'neural' in full accum mode is pretty atrocious now; I
think this is because when you have code like this:

  \(a :: Arr 1 R) ->
    let b = a
    in let c = b
       in sum d

then because the argument, as well as both let bindings, bind a value of
array type, each will introduce an accumulator, hence resulting in three
(!) nested `with` clauses that each just contribute their result back to
their parent. This is pointless, and we should fix this.

1 files changed, 4 insertions, 4 deletions

diff --git a/test/Main.hs b/test/Main.hs
index d18884e..b6f9f2b 100644
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -62,11 +62,11 @@ gradientByCHAD' = \simplIters env term input -> second (second (toTanE env input
     toTan typ primal der = case typ of
       STNil -> der
       STPair t1 t2 -> case der of
-                        Left () -> bimap (zeroTan t1) (zeroTan t2) primal
-                        Right (d₁, d₂) -> bimap (\p1 -> toTan t1 p1 d₁) (\p2 -> toTan t2 p2 d₂) primal
+                        Nothing -> bimap (zeroTan t1) (zeroTan t2) primal
+                        Just (d₁, d₂) -> bimap (\p1 -> toTan t1 p1 d₁) (\p2 -> toTan t2 p2 d₂) primal
       STEither t1 t2 -> case der of
-                          Left () -> bimap (zeroTan t1) (zeroTan t2) primal
-                          Right d -> case (primal, d) of
+                          Nothing -> bimap (zeroTan t1) (zeroTan t2) primal
+                          Just d -> case (primal, d) of
                             (Left p, Left d') -> Left (toTan t1 p d')
                             (Right p, Right d') -> Right (toTan t2 p d')
                             _ -> error "Primal and cotangent disagree on Either alternative"