From a0068469c57efcb482c193022042113f570572b3 Mon Sep 17 00:00:00 2001
From: Kiana Sheibani <kiana.a.sheibani@gmail.com>
Date: Mon, 25 Sep 2023 22:55:33 -0400
Subject: [PATCH] Revamp all of the standard array API

---
 src/Data/NP.idr                       |   5 +
 src/Data/NumIdr/Array.idr             |   2 +-
 src/Data/NumIdr/Array/Array.idr       | 274 ++++++++++++--------------
 src/Data/NumIdr/Array/Coords.idr      |  72 ++++---
 src/Data/NumIdr/Array/Rep.idr         | 231 ++++++++++++++++++++++
 src/Data/NumIdr/PrimArray.idr         | 148 +++++++++++---
 src/Data/NumIdr/PrimArray/Boxed.idr   |  33 +++-
 src/Data/NumIdr/PrimArray/Bytes.idr   | 193 ++++--------------
 src/Data/NumIdr/PrimArray/Delayed.idr |  21 +-
 src/Data/NumIdr/PrimArray/Linked.idr  |  40 ++++
 10 files changed, 655 insertions(+), 364 deletions(-)

diff --git a/src/Data/NP.idr b/src/Data/NP.idr
index 678a29a..6ee76e4 100644
--- a/src/Data/NP.idr
+++ b/src/Data/NP.idr
@@ -26,6 +26,11 @@ public export
       elems {all=[_]} [x] = show x
       elems {all=_::_} (x :: xs) = show x ++ ", " ++ elems xs
 
+-- use this when idris can't figure out the constraint above
+public export
+eqNP : forall f. (forall t. Eq (f t)) => (x, y : NP f ts) -> Bool
+eqNP [] [] = True
+eqNP (x :: xs) (y :: ys) = x == y && eqNP xs ys
 
 
 public export
diff --git a/src/Data/NumIdr/Array.idr b/src/Data/NumIdr/Array.idr
index fd81478..9efe967 100644
--- a/src/Data/NumIdr/Array.idr
+++ b/src/Data/NumIdr/Array.idr
@@ -3,4 +3,4 @@ module Data.NumIdr.Array
 import public Data.NP
 import public Data.NumIdr.Array.Array
 import public Data.NumIdr.Array.Coords
-import public Data.NumIdr.Array.Order
+import public Data.NumIdr.Array.Rep
diff --git a/src/Data/NumIdr/Array/Array.idr b/src/Data/NumIdr/Array/Array.idr
index 7d9c404..4768843 100644
--- a/src/Data/NumIdr/Array/Array.idr
+++ b/src/Data/NumIdr/Array/Array.idr
@@ -112,7 +112,7 @@ viewShape arr = rewrite shapeEq arr in
 export
 repeat : {default B rep : Rep} -> RepConstraint rep a =>
             (s : Vect rk Nat) -> a -> Array s a
-repeat s x = MkArray rep s (constant s x)
+repeat s x = MkArray rep s (PrimArray.constant s x)
 
 ||| Create an array filled with zeros.
 |||
@@ -138,9 +138,9 @@ ones {rep} s = repeat {rep} s 1
 ||| @ s   The shape of the constructed array
 ||| @ rep  The internal representation of the constructed array
 export
-fromVect : {default B rep : Rep} -> RepConstraint rep a =>
+fromVect : {default B rep : Rep} -> LinearRep rep => RepConstraint rep a =>
               (s : Vect rk Nat) -> Vect (product s) a -> Array s a
-fromVect s v = ?fv
+fromVect {rep} s v = MkArray rep s (PrimArray.fromList {rep} s $ toList v)
 
 
 ||| Create an array by taking values from a stream.
@@ -148,7 +148,7 @@ fromVect s v = ?fv
 ||| @ s   The shape of the constructed array
 ||| @ rep  The internal representation of the constructed array
 export
-fromStream : {default B rep : Rep} -> RepConstraint rep a =>
+fromStream : {default B rep : Rep} -> LinearRep rep => RepConstraint rep a =>
                 (s : Vect rk Nat) -> Stream a -> Array s a
 fromStream {rep} s str = fromVect {rep} s (take _ str)
 
@@ -211,12 +211,12 @@ index is (MkArray _ _ arr) = PrimArray.index is arr
 export %inline
 (!!) : Array s a -> Coords s -> a
 arr !! is = index is arr
-{-
+
 ||| Update the entry at the given coordinates using the function.
 export
 indexUpdate : Coords s -> (a -> a) -> Array s a -> Array s a
-indexUpdate is f (MkArray ord sts s arr) =
-  MkArray ord sts s (updateAt (getLocation sts is) f arr)
+indexUpdate is f (MkArray rep @{rc} s arr) =
+  MkArray rep @{rc} s (indexUpdate @{rc} is f arr)
 
 ||| Set the entry at the given coordinates to the given value.
 export
@@ -227,17 +227,8 @@ indexSet is = indexUpdate is . const
 ||| Index the array using the given range of coordinates, returning a new array.
 export
 indexRange : (rs : CoordsRange s) -> Array s a -> Array (newShape rs) a
-indexRange {s} rs arr with (viewShape arr)
-  _ | Shape s =
-    let ord = getOrder arr
-        sts = calcStrides ord s'
-    in  MkArray ord sts s'
-          (unsafeFromIns (product s') $
-            map (\(is,is') => (getLocation' sts is',
-                                index (getLocation' (strides arr) is) (getPrim arr)))
-            $ getCoordsList rs)
-  where s' : Vect ? Nat
-        s' = newShape rs
+indexRange rs (MkArray rep @{rc} s arr) =
+  MkArray rep @{rc} _ (PrimArray.indexRange @{rc} rs arr)
 
 ||| Index the array using the given range of coordinates, returning a new array.
 |||
@@ -250,13 +241,8 @@ arr !!.. rs = indexRange rs arr
 export
 indexSetRange : (rs : CoordsRange s) -> Array (newShape rs) a ->
                   Array s a -> Array s a
-indexSetRange rs rpl (MkArray ord sts s arr) =
-  MkArray ord sts s (unsafePerformIO $ do
-    let arr' = copy arr
-    unsafeDoIns (map (\(is,is') =>
-      (getLocation' sts is, index (getLocation' (strides rpl) is') (getPrim rpl)))
-        $ getCoordsList rs) arr'
-    pure arr')
+indexSetRange rs (MkArray _ _ rpl) (MkArray rep s arr) =
+  MkArray rep s (PrimArray.indexSetRange {rep} rs (convertRep rpl) arr)
 
 
 ||| Update the sub-array at the given range of coordinates by applying
@@ -266,13 +252,14 @@ indexUpdateRange : (rs : CoordsRange s) ->
                     (Array (newShape rs) a -> Array (newShape rs) a) ->
                     Array s a -> Array s a
 indexUpdateRange rs f arr = indexSetRange rs (f $ arr !!.. rs) arr
--}
+
 
 ||| Index the array using the given coordinates, returning `Nothing` if the
 ||| coordinates are out of bounds.
 export
 indexNB : Vect rk Nat -> Array {rk} s a -> Maybe a
-indexNB is (MkArray _ _ arr) = PrimArray.indexNB is arr
+indexNB is (MkArray rep @{rc} s arr) =
+  map (\is => index is (MkArray rep @{rc} s arr)) (validateCoords s is)
 
 ||| Index the array using the given coordinates, returning `Nothing` if the
 ||| coordinates are out of bounds.
@@ -281,15 +268,13 @@ indexNB is (MkArray _ _ arr) = PrimArray.indexNB is arr
 export %inline
 (!?) : Array {rk} s a -> Vect rk Nat -> Maybe a
 arr !? is = indexNB is arr
-{-
+
 ||| Update the entry at the given coordinates using the function. `Nothing` is
 ||| returned if the coordinates are out of bounds.
 export
 indexUpdateNB : Vect rk Nat -> (a -> a) -> Array {rk} s a -> Maybe (Array s a)
-indexUpdateNB is f (MkArray ord sts s arr) =
-  if all id $ zipWith (<) is s
-  then Just $ MkArray ord sts s (updateAt (getLocation' sts is) f arr)
-  else Nothing
+indexUpdateNB is f (MkArray rep @{rc} s arr) =
+  map (\is => indexUpdate is f (MkArray rep @{rc} s arr)) (validateCoords s is)
 
 ||| Set the entry at the given coordinates using the function. `Nothing` is
 ||| returned if the coordinates are out of bounds.
@@ -302,20 +287,8 @@ indexSetNB is = indexUpdateNB is . const
 ||| If any of the given indices are out of bounds, then `Nothing` is returned.
 export
 indexRangeNB : (rs : Vect rk CRangeNB) -> Array s a -> Maybe (Array (newShape s rs) a)
-indexRangeNB {s} rs arr with (viewShape arr)
-  _ | Shape s =
-    if validateShape s rs
-    then
-      let ord = getOrder arr
-          sts = calcStrides ord s'
-      in  Just $ MkArray ord sts s'
-            (unsafeFromIns (product s') $
-              map (\(is,is') => (getLocation' sts is',
-                                  index (getLocation' (strides arr) is) (getPrim arr)))
-              $ getCoordsList s rs)
-    else Nothing
-  where s' : Vect ? Nat
-        s' = newShape s rs
+indexRangeNB rs (MkArray rep @{rc} s arr) =
+  map (\rs => believe_me $ Array.indexRange rs (MkArray rep @{rc} s arr)) (validateCRange s rs)
 
 ||| Index the array using the given range of coordinates, returning a new array.
 ||| If any of the given indices are out of bounds, then `Nothing` is returned.
@@ -324,7 +297,7 @@ indexRangeNB {s} rs arr with (viewShape arr)
 export %inline
 (!?..) : Array s a -> (rs : Vect rk CRangeNB) -> Maybe (Array (newShape s rs) a)
 arr !?.. rs = indexRangeNB rs arr
--}
+
 
 ||| Index the array using the given coordinates.
 ||| WARNING: This function does not perform any bounds check on its inputs.
@@ -342,30 +315,21 @@ export %inline
 (!#) : Array {rk} s a -> Vect rk Nat -> a
 arr !# is = indexUnsafe is arr
 
-{-
+
 ||| Index the array using the given range of coordinates, returning a new array.
 ||| WARNING: This function does not perform any bounds check on its inputs.
 ||| Misuse of this function can easily break memory safety.
-export
+export %unsafe
 indexRangeUnsafe : (rs : Vect rk CRangeNB) -> Array s a -> Array (newShape s rs) a
-indexRangeUnsafe {s} rs arr with (viewShape arr)
-  _ | Shape s =
-    let ord = getOrder arr
-        sts = calcStrides ord s'
-    in  MkArray ord sts s'
-          (unsafeFromIns (product s') $
-            map (\(is,is') => (getLocation' sts is',
-                                index (getLocation' (strides arr) is) (getPrim arr)))
-            $ getCoordsList s rs)
-  where s' : Vect ? Nat
-        s' = newShape s rs
+indexRangeUnsafe rs (MkArray rep @{rc} s arr) =
+  believe_me $ Array.indexRange (assertCRange s rs) (MkArray rep @{rc} s arr)
 
 ||| Index the array using the given range of coordinates, returning a new array.
 ||| WARNING: This function does not perform any bounds check on its inputs.
 ||| Misuse of this function can easily break memory safety.
 |||
 ||| This is the operator form of `indexRangeUnsafe`.
-export %inline
+export %inline %unsafe
 (!#..) : Array s a -> (rs : Vect rk CRangeNB) -> Array (newShape s rs) a
 arr !#.. is = indexRangeUnsafe is arr
 
@@ -375,35 +339,42 @@ arr !#.. is = indexRangeUnsafe is arr
 -- Operations on arrays
 --------------------------------------------------------------------------------
 
-
-||| Reshape the array into the given shape and reinterpret it according to
-||| the given order.
-|||
-||| @ s'  The shape to convert the array to
-||| @ ord The order to reinterpret the array by
 export
-reshape' : (s' : Vect rk' Nat) -> (ord : Order) -> Array {rk} s a ->
-             (0 ok : product s = product s') => Array s' a
-reshape' s' ord' arr = MkArray ord' (calcStrides ord' s') s' (getPrim arr)
+mapArray' : (a -> a) -> Array s a -> Array s a
+mapArray' f (MkArray rep _ arr) = MkArray rep _ (mapPrim f arr)
+
+export
+mapArray : (a -> b) -> (arr : Array s a) -> RepConstraint (getRep arr) b => Array s b
+mapArray f (MkArray rep _ arr) @{rc} = MkArray rep @{rc} _ (mapPrim f arr)
+
+export
+zipWithArray' : (a -> a -> a) -> Array s a -> Array s a -> Array s a
+zipWithArray' {s} f a b with (viewShape a)
+  _ | Shape s = MkArray (mergeRep (getRep a) (getRep b))
+                          @{mergeRepConstraint (getRepC a) (getRepC b)} s
+                          $ PrimArray.fromFunctionNB @{mergeRepConstraint (getRepC a) (getRepC b)} _
+                              (\is => f (a !# is) (b !# is))
+
+export
+zipWithArray : (a -> b -> c) -> (arr : Array s a) -> (arr' : Array s b) ->
+                RepConstraint (mergeRep (getRep arr) (getRep arr')) c => Array s c
+zipWithArray {s} f a b @{rc} with (viewShape a)
+  _ | Shape s = MkArray (mergeRep (getRep a) (getRep b)) @{rc} s
+                          $ PrimArray.fromFunctionNB _ (\is => f (a !# is) (b !# is))
+
 
 ||| Reshape the array into the given shape.
 |||
 ||| @ s' The shape to convert the array to
 export
-reshape : (s' : Vect rk' Nat) -> Array {rk} s a ->
+reshape : (s' : Vect rk' Nat) -> (arr : Array {rk} s a) -> LinearRep (getRep arr) =>
             (0 ok : product s = product s') => Array s' a
-reshape s' arr = reshape' s' (getOrder arr) arr
-
+reshape s' (MkArray rep _ arr) = MkArray rep s' (PrimArray.reshape s' arr)
 
 ||| Change the internal order of the array's elements.
 export
-reorder : Order -> Array s a -> Array s a
-reorder {s} ord' arr with (viewShape arr)
-  _ | Shape s = let sts = calcStrides ord' s
-                in  MkArray ord' sts _ (unsafeFromIns (product s) $
-                      map (\is => (getLocation' sts is, index (getLocation' (strides arr) is) (getPrim arr))) $
-                      getAllCoords' s)
-
+convertRep : (rep : Rep) -> RepConstraint rep a => Array s a -> Array s a
+convertRep rep (MkArray _ s arr) = MkArray rep s (PrimArray.convertRep arr)
 
 ||| Resize the array to a new shape, preserving the coordinates of the original
 ||| elements. New coordinates are filled with a default value.
@@ -412,7 +383,7 @@ reorder {s} ord' arr with (viewShape arr)
 ||| @ def The default value to fill the array with
 export
 resize : (s' : Vect rk Nat) -> (def : a) -> Array {rk} s a -> Array s' a
-resize s' def arr = fromFunction' s' (getOrder arr) (fromMaybe def . (arr !?) . toNB)
+resize s' def arr = fromFunction {rep=getRep arr} @{getRepC arr} s' (fromMaybe def . (arr !?) . toNB)
 
 ||| Resize the array to a new shape, preserving the coordinates of the original
 ||| elements. This function requires a proof that the new shape is strictly
@@ -427,20 +398,11 @@ resizeLTE : (s' : Vect rk Nat) -> (0 ok : NP Prelude.id (zipWith LTE s' s)) =>
 resizeLTE s' arr = resize s' (believe_me ()) arr
 
 
-||| List all of the values in an array in row-major order.
-export
-elements : Array {rk} s a -> Vect (product s) a
-elements (MkArray _ sts sh p) =
-  let elems = map (flip index p . getLocation' sts) (getAllCoords' sh)
-  -- TODO: prove that the number of elements is `product s`
-  in assert_total $ case toVect (product sh) elems of Just v => v
-
-
 ||| List all of the values in an array along with their coordinates.
 export
 enumerateNB : Array {rk} s a -> List (Vect rk Nat, a)
-enumerateNB (MkArray _ sts sh p) =
-  map (\is => (is, index (getLocation' sts is) p)) (getAllCoords' sh)
+enumerateNB (MkArray _ s arr) =
+  map (\is => (is, PrimArray.indexUnsafe is arr)) (getAllCoords' s)
 
 ||| List all of the values in an array along with their coordinates.
 export
@@ -448,6 +410,12 @@ enumerate : Array s a -> List (Coords s, a)
 enumerate {s} arr with (viewShape arr)
   _ | Shape s = map (\is => (is, index is arr)) (getAllCoords s)
 
+||| List all of the values in an array in row-major order.
+export
+elements : Array {rk} s a -> Vect (product s) a
+elements (MkArray _ s arr) =
+  believe_me $ Vect.fromList $
+    map (flip PrimArray.indexUnsafe arr) (getAllCoords' s)
 
 ||| Join two arrays along a particular axis, e.g. combining two matrices
 ||| vertically or horizontally. All other axes of the arrays must have the
@@ -457,16 +425,12 @@ enumerate {s} arr with (viewShape arr)
 export
 concat : (axis : Fin rk) -> Array {rk} s a -> Array (replaceAt axis d s) a ->
           Array (updateAt axis (+d) s) a
-concat axis a b = let sA = shape a
-                      sB = shape b
-                      dA = index axis sA
-                      dB = index axis sB
-                      s = replaceAt axis (dA + dB) sA
-                      sts = calcStrides COrder s
-                      ins = map (mapFst $ getLocation' sts . toNB) (enumerate a)
-                            ++ map (mapFst $ getLocation' sts . updateAt axis (+dA) . toNB) (enumerate b)
-                      -- TODO: prove that the type-level shape and `s` are equivalent
-                  in  believe_me $ MkArray COrder sts s (unsafeFromIns (product s) ins)
+concat {s,d} axis a b with (viewShape a, viewShape b)
+  _ | (Shape s, Shape (replaceAt axis d s)) =
+    believe_me $ Array.fromFunctionNB {rep=mergeRep (getRep a) (getRep b)}
+                  @{mergeRepConstraint (getRepC a) (getRepC b)} (updateAt axis (+ index axis (shape b)) s)
+      (\is => let limit = index axis s
+              in if index axis is < limit then a !# is else b !# updateAt axis (`minus` limit) is)
 
 ||| Stack multiple arrays along a new axis, e.g. stacking vectors to form a matrix.
 |||
@@ -500,12 +464,11 @@ splitAxes : (rk : Nat) -> {0 rk' : Nat} -> {s : _} ->
             Array {rk=rk+rk'} s a -> Array (take {m=rk'} rk s) (Array (drop {m=rk'} rk s) a)
 splitAxes _ {s} arr = fromFunctionNB _ (\is => fromFunctionNB _ (\is' => arr !# (is ++ is')))
 
-
 ||| Construct the transpose of an array by reversing the order of its axes.
 export
 transpose : Array s a -> Array (reverse s) a
 transpose {s} arr with (viewShape arr)
-  _ | Shape s = fromFunctionNB (reverse s) (\is => arr !# reverse is)
+  _ | Shape s = fromFunctionNB _ (\is => arr !# reverse is)
 
 ||| Construct the transpose of an array by reversing the order of its axes.
 |||
@@ -551,41 +514,56 @@ permuteInAxis {s} axis p arr with (viewShape arr)
 -- Implementations
 --------------------------------------------------------------------------------
 
-
--- Most of these implementations apply the operation pointwise. If there are
--- multiple arrays involved with different orders, then all of the arrays are
--- reordered to match one.
-
-
 export
 Zippable (Array s) where
   zipWith {s} f a b with (viewShape a)
-    _ | Shape s = MkArray (getOrder a) (strides a) s $
-                    if getOrder a == getOrder b
-                      then unsafeZipWith f (getPrim a) (getPrim b)
-                      else unsafeZipWith f (getPrim a) (getPrim $ reorder (getOrder a) b)
+    _ | Shape s = MkArray (mergeRepNC (getRep a) (getRep b))
+                          @{mergeNCRepConstraint} s
+                          $ PrimArray.fromFunctionNB @{mergeNCRepConstraint} _
+                              (\is => f (a !# is) (b !# is))
 
   zipWith3 {s} f a b c with (viewShape a)
-    _ | Shape s = MkArray (getOrder a) (strides a) s $
-                    if (getOrder a == getOrder b) && (getOrder b == getOrder c)
-                        then unsafeZipWith3 f (getPrim a) (getPrim b) (getPrim c)
-                        else unsafeZipWith3 f (getPrim a) (getPrim $ reorder (getOrder a) b)
-                                                          (getPrim $ reorder (getOrder a) c)
+    _ | Shape s = MkArray (mergeRepNC (mergeRep (getRep a) (getRep b)) (getRep c))
+                          @{mergeNCRepConstraint} s
+                          $ PrimArray.fromFunctionNB @{mergeNCRepConstraint} _
+                              (\is => f (a !# is) (b !# is) (c !# is))
 
   unzipWith {s} f arr with (viewShape arr)
-    _ | Shape s = case unzipWith f (getPrim arr) of
-                    (a, b) => (MkArray (getOrder arr) (strides arr) s a,
-                               MkArray (getOrder arr) (strides arr) s b)
+    _ | Shape s =
+      let rep : Rep
+          rep = forceRepNC $ getRep arr
+      in  (MkArray rep
+             @{forceRepConstraint} s
+             $ PrimArray.fromFunctionNB @{forceRepConstraint} _
+                 (\is => fst $ f (arr !# is)),
+           MkArray rep
+             @{forceRepConstraint} s
+             $ PrimArray.fromFunctionNB @{forceRepConstraint} _
+                 (\is => snd $ f (arr !# is)))
 
   unzipWith3 {s} f arr with (viewShape arr)
-    _ | Shape s = case unzipWith3 f (getPrim arr) of
-                    (a, b, c) => (MkArray (getOrder arr) (strides arr) s a,
-                                  MkArray (getOrder arr) (strides arr) s b,
-                                  MkArray (getOrder arr) (strides arr) s c)
+    _ | Shape s =
+      let rep : Rep
+          rep = forceRepNC $ getRep arr
+      in  (MkArray rep
+             @{forceRepConstraint} s
+             $ PrimArray.fromFunctionNB @{forceRepConstraint} _
+                 (\is => fst $ f (arr !# is)),
+           MkArray rep
+             @{forceRepConstraint} s
+             $ PrimArray.fromFunctionNB @{forceRepConstraint} _
+                 (\is => fst $ snd $ f (arr !# is)),
+           MkArray rep
+             @{forceRepConstraint} s
+             $ PrimArray.fromFunctionNB @{forceRepConstraint} _
+                 (\is => snd $ snd $ f (arr !# is)))
+
 
 export
 Functor (Array s) where
-  map f (MkArray ord sts s arr) = MkArray ord sts s (map f arr)
+  map f (MkArray rep @{rc} s arr) = MkArray (forceRepNC rep) @{forceRepConstraint} s
+                                (mapPrim @{forceRepConstraint} @{forceRepConstraint} f
+                                  $ convertRep @{rc} @{forceRepConstraint} arr)
 
 export
 {s : _} -> Applicative (Array s) where
@@ -602,15 +580,18 @@ export
 
 export
 Foldable (Array s) where
-  foldl f z = foldl f z . getPrim
-  foldr f z = foldr f z . getPrim
-  null arr = size arr == Z
-  toList = toList . getPrim
+  foldl f z (MkArray _ _ arr) = PrimArray.foldl f z arr
+  foldr f z (MkArray _ _ arr) = PrimArray.foldr f z arr
+  null (MkArray _ s _) = isZero (product s)
+
 
 export
 Traversable (Array s) where
-  traverse f (MkArray ord sts s arr) =
-    map (MkArray ord sts s) (traverse f arr)
+  traverse f (MkArray rep @{rc} s arr) =
+    map (MkArray (forceRepNC rep) @{forceRepConstraint} s)
+      (PrimArray.traverse {rep=forceRepNC rep}
+        @{%search} @{forceRepConstraint} @{forceRepConstraint} f
+        (PrimArray.convertRep @{rc} @{forceRepConstraint} arr))
 
 
 export
@@ -619,13 +600,11 @@ Cast a b => Cast (Array s a) (Array s b) where
 
 export
 Eq a => Eq (Array s a) where
-  a == b = if getOrder a == getOrder b
-              then unsafeEq (getPrim a) (getPrim b)
-              else unsafeEq (getPrim a) (getPrim $ reorder (getOrder a) b)
+  a == b = and $ zipWith (delay .: (==)) (convertRep D a) (convertRep D b)
 
 export
 Semigroup a => Semigroup (Array s a) where
-  (<+>) = zipWith (<+>)
+  (<+>) = zipWithArray' (<+>)
 
 export
 {s : _} -> Monoid a => Monoid (Array s a) where
@@ -635,36 +614,34 @@ export
 -- were moved into its own interface, this constraint could be removed.
 export
 {s : _} -> Num a => Num (Array s a) where
-  (+) = zipWith (+)
-  (*) = zipWith (*)
+  (+) = zipWithArray' (+)
+  (*) = zipWithArray' (*)
 
   fromInteger = repeat s . fromInteger
 
 export
 {s : _} -> Neg a => Neg (Array s a) where
-  negate = map negate
-  (-) = zipWith (-)
+  negate = mapArray' negate
+  (-) = zipWithArray' (-)
 
 export
 {s : _} -> Fractional a => Fractional (Array s a) where
-  recip = map recip
-  (/) = zipWith (/)
+  recip = mapArray' recip
+  (/) = zipWithArray' (/)
 
 
 export
 Num a => Mult a (Array {rk} s a) (Array s a) where
-  (*.) x = map (*x)
+  (*.) x = mapArray' (*x)
 
 export
 Num a => Mult (Array {rk} s a) a (Array s a) where
   (*.) = flip (*.)
 
 
-
 export
 Show a => Show (Array s a) where
-  showPrec d arr = let orderedElems = PrimArray.toList $ getPrim $
-                         if getOrder arr == COrder then arr else reorder COrder arr
+  showPrec d arr = let orderedElems = toList $ elements arr
                    in  showCon d "array " $ concat $ insertPunct (shape arr) $ map show orderedElems
     where
       splitWindow : Nat -> List String -> List (List String)
@@ -691,7 +668,7 @@ Show a => Show (Array s a) where
 ||| Linearly interpolate between two arrays.
 export
 lerp : Neg a => a -> Array s a -> Array s a -> Array s a
-lerp t a b = zipWith (+) (a *. (1 - t)) (b *. t)
+lerp t a b = zipWithArray' (+) (a *. (1 - t)) (b *. t)
 
 
 ||| Calculate the square of an array's Eulidean norm.
@@ -715,4 +692,3 @@ normalize arr = if all (==0) arr then arr else map (/ norm arr) arr
 export
 pnorm : (p : Double) -> Array s Double -> Double
 pnorm p = (`pow` recip p) . sum . map (`pow` p)
--}
diff --git a/src/Data/NumIdr/Array/Coords.idr b/src/Data/NumIdr/Array/Coords.idr
index 21ac2cd..03b021e 100644
--- a/src/Data/NumIdr/Array/Coords.idr
+++ b/src/Data/NumIdr/Array/Coords.idr
@@ -43,6 +43,11 @@ toNB : Coords {rk} s -> Vect rk Nat
 toNB [] = []
 toNB (i :: is) = finToNat i :: toNB is
 
+export
+validateCoords : (s : Vect rk Nat) -> Vect rk Nat -> Maybe (Coords s)
+validateCoords [] [] = Just []
+validateCoords (d :: s) (i :: is) = (::) <$> natToFin i d <*> validateCoords s is
+
 
 namespace Strict
   public export
@@ -155,6 +160,44 @@ namespace Strict
 
 namespace NB
   export
+  validateCRange : (s : Vect rk Nat) -> Vect rk CRangeNB -> Maybe (CoordsRange s)
+  validateCRange [] [] = Just []
+  validateCRange (d :: s) (r :: rs) = [| validate' d r :: validateCRange s rs |]
+    where
+      validate' : (n : Nat) -> CRangeNB -> Maybe (CRange n)
+      validate' n All = Just All
+      validate' n (StartBound x) =
+        case isLTE x n of
+          Yes _ => Just (StartBound (natToFinLT x))
+          _ => Nothing
+      validate' n (EndBound x) =
+        case isLTE x n of
+          Yes _ => Just (EndBound (natToFinLT x))
+          _ => Nothing
+      validate' n (Bounds x y) =
+        case (isLTE x n, isLTE y n) of
+          (Yes _, Yes _) => Just (Bounds (natToFinLT x) (natToFinLT y))
+          _ => Nothing
+      validate' n (Indices xs) = Indices <$> traverse
+        (\x => case isLT x n of
+                Yes _ => Just (natToFinLT x)
+                No _ => Nothing) xs
+      validate' n (Filter f) = Just (Filter (f . finToNat))
+
+  export %unsafe
+  assertCRange : (s : Vect rk Nat) -> Vect rk CRangeNB -> CoordsRange s
+  assertCRange [] [] = []
+  assertCRange (d :: s) (r :: rs) = assert' d r :: assertCRange s rs
+    where
+      assert' : (n : Nat) -> CRangeNB -> CRange n
+      assert' n All = All
+      assert' n (StartBound x) = StartBound (believe_me x)
+      assert' n (EndBound x) = EndBound (believe_me x)
+      assert' n (Bounds x y) = Bounds (believe_me x) (believe_me y)
+      assert' n (Indices xs) = Indices (believe_me <$> xs)
+      assert' n (Filter f) = Filter (f . finToNat)
+
+  public export
   cRangeNBToList : Nat -> CRangeNB -> List Nat
   cRangeNBToList s All = range 0 s
   cRangeNBToList s (StartBound x) = range x s
@@ -163,38 +206,11 @@ namespace NB
   cRangeNBToList s (Indices xs) = nub xs
   cRangeNBToList s (Filter p) = filter p $ range 0 s
 
-  export
-  validateCRangeNB : Nat -> CRangeNB -> Bool
-  validateCRangeNB s All = True
-  validateCRangeNB s (StartBound x) = x < s
-  validateCRangeNB s (EndBound x) = x <= s
-  validateCRangeNB s (Bounds x y) = x < s && y <= s
-  validateCRangeNB s (Indices xs) = all (<s) xs
-  validateCRangeNB s (Filter p) = True
-
   ||| Calculate the new shape given by a coordinate range.
-  export
+  public export
   newShape : Vect rk Nat -> Vect rk CRangeNB -> Vect rk Nat
   newShape = zipWith (length .: cRangeNBToList)
 
-  export
-  validateShape : Vect rk Nat -> Vect rk CRangeNB -> Bool
-  validateShape = all id .: zipWith validateCRangeNB
-
-  export
-  getNewPos : Vect rk Nat -> Vect rk CRangeNB -> Vect rk Nat -> Vect rk Nat
-  getNewPos = zipWith3 (\d,r,i => assert_total $
-    case findIndex (==i) (cRangeNBToList d r) of Just x => cast x)
-
-  export
-  getCoordsList : Vect rk Nat -> Vect rk CRangeNB -> List (Vect rk Nat, Vect rk Nat)
-  getCoordsList s rs = map (\is => (is, getNewPos s rs is)) $ go s rs
-    where
-      go : {0 rk : _} -> Vect rk Nat -> Vect rk CRangeNB -> List (Vect rk Nat)
-      go [] [] = [[]]
-      go (d :: s) (r :: rs) = [| cRangeNBToList d r :: go s rs |]
-
-
 export
 getAllCoords' : Vect rk Nat -> List (Vect rk Nat)
 getAllCoords' = traverse (\case Z => []; S n => [0..n])
diff --git a/src/Data/NumIdr/Array/Rep.idr b/src/Data/NumIdr/Array/Rep.idr
index 31b5ab5..3410d13 100644
--- a/src/Data/NumIdr/Array/Rep.idr
+++ b/src/Data/NumIdr/Array/Rep.idr
@@ -1,6 +1,8 @@
 module Data.NumIdr.Array.Rep
 
 import Data.Vect
+import Data.Bits
+import Data.Buffer
 
 %default total
 
@@ -23,6 +25,8 @@ data Order : Type where
   ||| fashion (the first axis is the least significant).
   FOrder : Order
 
+%name Order o
+
 
 public export
 Eq Order where
@@ -52,6 +56,9 @@ data Rep : Type where
   Linked : Rep
   Delayed : Rep
 
+%name Rep rep
+
+
 public export
 B : Rep
 B = Boxed COrder
@@ -65,7 +72,231 @@ D : Rep
 D = Delayed
 
 
+public export
+Eq Rep where
+  Bytes o == Bytes o' = o == o'
+  Boxed o == Boxed o' = o == o'
+  Linked == Linked = True
+  Delayed == Delayed = True
+  _ == _ = False
+
 public export
 data LinearRep : Rep -> Type where
   BytesIsL : LinearRep (Bytes o)
   BoxedIsL : LinearRep (Boxed o)
+
+
+public export
+forceRepNC : Rep -> Rep
+forceRepNC (Bytes o) = Boxed o
+forceRepNC r = r
+
+public export
+mergeRep : Rep -> Rep -> Rep
+mergeRep r r' = if r == Delayed || r' == Delayed then Delayed else r
+
+public export
+mergeRepNC : Rep -> Rep -> Rep
+mergeRepNC r r' =
+  if r == Delayed || r' == Delayed then Delayed
+  else case r of
+        Bytes _ => case r' of
+                    Bytes o => Boxed o
+                    _ => r'
+        _ => r
+
+public export
+data NoConstraintRep : Rep -> Type where
+  BoxedNC : NoConstraintRep (Boxed o)
+  LinkedNC : NoConstraintRep Linked
+  DelayedNC : NoConstraintRep Delayed
+
+public export
+mergeRepNCCorrect : (r, r' : Rep) -> NoConstraintRep (mergeRepNC r r')
+mergeRepNCCorrect Delayed _ = DelayedNC
+mergeRepNCCorrect (Bytes y) (Bytes x) = BoxedNC
+mergeRepNCCorrect (Boxed y) (Bytes x) = BoxedNC
+mergeRepNCCorrect Linked (Bytes x) = LinkedNC
+mergeRepNCCorrect (Bytes y) (Boxed x) = BoxedNC
+mergeRepNCCorrect (Boxed y) (Boxed x) = BoxedNC
+mergeRepNCCorrect Linked (Boxed x) = LinkedNC
+mergeRepNCCorrect (Bytes x) Linked = LinkedNC
+mergeRepNCCorrect (Boxed x) Linked = BoxedNC
+mergeRepNCCorrect Linked Linked = LinkedNC
+mergeRepNCCorrect (Bytes x) Delayed = DelayedNC
+mergeRepNCCorrect (Boxed x) Delayed = DelayedNC
+mergeRepNCCorrect Linked Delayed = DelayedNC
+
+public export
+forceRepNCCorrect : (r : Rep) -> NoConstraintRep (forceRepNC r)
+forceRepNCCorrect (Bytes x) = BoxedNC
+forceRepNCCorrect (Boxed x) = BoxedNC
+forceRepNCCorrect Linked = LinkedNC
+forceRepNCCorrect Delayed = DelayedNC
+
+
+--------------------------------------------------------------------------------
+-- Byte representations of elements
+--------------------------------------------------------------------------------
+
+
+public export
+interface ByteRep a where
+  bytes : Nat
+
+  toBytes : a -> Vect bytes Bits8
+  fromBytes : Vect bytes Bits8 -> a
+
+export
+ByteRep Bits8 where
+  bytes = 1
+
+  toBytes x = [x]
+  fromBytes [x] = x
+
+export
+ByteRep Bits16 where
+  bytes = 2
+
+  toBytes x = [cast (x `shiftR` 8), cast x]
+  fromBytes [b1,b2] = cast b1 `shiftL` 8 .|. cast b2
+
+export
+ByteRep Bits32 where
+  bytes = 4
+
+  toBytes x = [cast (x `shiftR` 24),
+               cast (x `shiftR` 16),
+               cast (x `shiftR` 8),
+               cast x]
+  fromBytes [b1,b2,b3,b4] =
+    cast b1 `shiftL` 24 .|.
+    cast b2 `shiftL` 16 .|.
+    cast b3 `shiftL` 8 .|.
+    cast b4
+
+export
+ByteRep Bits64 where
+  bytes = 8
+
+  toBytes x = [cast (x `shiftR` 56),
+               cast (x `shiftR` 48),
+               cast (x `shiftR` 40),
+               cast (x `shiftR` 32),
+               cast (x `shiftR` 24),
+               cast (x `shiftR` 16),
+               cast (x `shiftR` 8),
+               cast x]
+  fromBytes [b1,b2,b3,b4,b5,b6,b7,b8] =
+    cast b1 `shiftL` 56 .|.
+    cast b2 `shiftL` 48 .|.
+    cast b3 `shiftL` 40 .|.
+    cast b4 `shiftL` 32 .|.
+    cast b5 `shiftL` 24 .|.
+    cast b6 `shiftL` 16 .|.
+    cast b7 `shiftL` 8 .|.
+    cast b8
+
+export
+ByteRep Int where
+  bytes = 8
+
+  toBytes x = [cast (x `shiftR` 56),
+               cast (x `shiftR` 48),
+               cast (x `shiftR` 40),
+               cast (x `shiftR` 32),
+               cast (x `shiftR` 24),
+               cast (x `shiftR` 16),
+               cast (x `shiftR` 8),
+               cast x]
+  fromBytes [b1,b2,b3,b4,b5,b6,b7,b8] =
+    cast b1 `shiftL` 56 .|.
+    cast b2 `shiftL` 48 .|.
+    cast b3 `shiftL` 40 .|.
+    cast b4 `shiftL` 32 .|.
+    cast b5 `shiftL` 24 .|.
+    cast b6 `shiftL` 16 .|.
+    cast b7 `shiftL` 8 .|.
+    cast b8
+
+export
+ByteRep Int8 where
+  bytes = 1
+
+  toBytes x = [cast x]
+  fromBytes [x] = cast x
+
+export
+ByteRep Int16 where
+  bytes = 2
+
+  toBytes x = [cast (x `shiftR` 8), cast x]
+  fromBytes [b1,b2] = cast b1 `shiftL` 8 .|. cast b2
+
+export
+ByteRep Int32 where
+  bytes = 4
+
+  toBytes x = [cast (x `shiftR` 24),
+               cast (x `shiftR` 16),
+               cast (x `shiftR` 8),
+               cast x]
+  fromBytes [b1,b2,b3,b4] =
+    cast b1 `shiftL` 24 .|.
+    cast b2 `shiftL` 16 .|.
+    cast b3 `shiftL` 8 .|.
+    cast b4
+
+export
+ByteRep Int64 where
+  bytes = 8
+
+  toBytes x = [cast (x `shiftR` 56),
+               cast (x `shiftR` 48),
+               cast (x `shiftR` 40),
+               cast (x `shiftR` 32),
+               cast (x `shiftR` 24),
+               cast (x `shiftR` 16),
+               cast (x `shiftR` 8),
+               cast x]
+  fromBytes [b1,b2,b3,b4,b5,b6,b7,b8] =
+    cast b1 `shiftL` 56 .|.
+    cast b2 `shiftL` 48 .|.
+    cast b3 `shiftL` 40 .|.
+    cast b4 `shiftL` 32 .|.
+    cast b5 `shiftL` 24 .|.
+    cast b6 `shiftL` 16 .|.
+    cast b7 `shiftL` 8 .|.
+    cast b8
+
+export
+ByteRep Bool where
+  bytes = 1
+
+  toBytes b = [if b then 1 else 0]
+  fromBytes [x] = x /= 0
+
+export
+ByteRep a => ByteRep b => ByteRep (a, b) where
+  bytes = bytes {a} + bytes {a=b}
+
+  toBytes (x,y) = toBytes x ++ toBytes y
+  fromBytes = bimap fromBytes fromBytes . splitAt _
+
+export
+{n : _} -> ByteRep a => ByteRep (Vect n a) where
+  bytes = n * bytes {a}
+
+  toBytes xs = concat $ map toBytes xs
+  fromBytes {n = 0} bs = []
+  fromBytes {n = S n} bs =
+    let (bs1, bs2) = splitAt _ bs
+    in  fromBytes bs1 :: fromBytes bs2
+
+
+public export
+RepConstraint : Rep -> Type -> Type
+RepConstraint (Bytes _) a = ByteRep a
+RepConstraint (Boxed _) a = ()
+RepConstraint Linked a = ()
+RepConstraint Delayed a = ()
diff --git a/src/Data/NumIdr/PrimArray.idr b/src/Data/NumIdr/PrimArray.idr
index a4e958f..d7d1009 100644
--- a/src/Data/NumIdr/PrimArray.idr
+++ b/src/Data/NumIdr/PrimArray.idr
@@ -2,23 +2,39 @@ module Data.NumIdr.PrimArray
 
 import Data.Buffer
 import Data.Vect
+import Data.Fin
 import Data.NP
 import Data.NumIdr.Array.Rep
 import Data.NumIdr.Array.Coords
-import Data.NumIdr.PrimArray.Bytes
-import Data.NumIdr.PrimArray.Boxed
-import Data.NumIdr.PrimArray.Linked
-import Data.NumIdr.PrimArray.Delayed
+import public Data.NumIdr.PrimArray.Bytes
+import public Data.NumIdr.PrimArray.Boxed
+import public Data.NumIdr.PrimArray.Linked
+import public Data.NumIdr.PrimArray.Delayed
 
 %default total
 
 
-public export
-RepConstraint : Rep -> Type -> Type
-RepConstraint (Bytes _) a = ByteRep a
-RepConstraint (Boxed _) a = ()
-RepConstraint Linked a = ()
-RepConstraint Delayed a = ()
+
+noRCCorrect : (rep : Rep) -> NoConstraintRep rep -> RepConstraint rep a
+noRCCorrect (Boxed _) BoxedNC = ()
+noRCCorrect Linked LinkedNC = ()
+noRCCorrect Delayed DelayedNC = ()
+
+export
+mergeRepConstraint : {r, r' : Rep} -> RepConstraint r a -> RepConstraint r' a ->
+                      RepConstraint (mergeRep r r') a
+mergeRepConstraint {r,r'} a b with (r == Delayed || r' == Delayed)
+  _ | True = ()
+  _ | False = a
+
+export
+mergeNCRepConstraint : {r, r' : Rep} -> RepConstraint (mergeRepNC r r') a
+mergeNCRepConstraint = noRCCorrect _ (mergeRepNCCorrect r r')
+
+export
+forceRepConstraint : {r : Rep} -> RepConstraint (forceRepNC r) a
+forceRepConstraint = noRCCorrect _ (forceRepNCCorrect r)
+
 
 
 export
@@ -29,6 +45,11 @@ PrimArray Linked s a = Vects s a
 PrimArray Delayed s a = Coords s -> a
 
 
+export
+reshape : {rep : Rep} -> LinearRep rep => RepConstraint rep a => (s' : Vect rk Nat) -> PrimArray rep s a -> PrimArray rep s' a
+reshape {rep = Bytes o} s' (MkPABytes _ arr) = MkPABytes (calcStrides o s') arr
+reshape {rep = Boxed o} s' (MkPABoxed _ arr) = MkPABoxed (calcStrides o s') arr
+
 export
 constant : {rep : Rep} -> RepConstraint rep a => (s : Vect rk Nat) -> a -> PrimArray rep s a
 constant {rep = Bytes o} = Bytes.constant
@@ -66,25 +87,68 @@ index {rep = Linked} is arr = Linked.index is arr
 index {rep = Delayed} is arr = arr is
 
 export
-indexNB : {rep,s : _} -> RepConstraint rep a => Vect rk Nat -> PrimArray {rk} rep s a -> Maybe a
-indexNB {rep = Bytes o} is arr@(MkPABytes sts _) =
-  if and (zipWith (delay .: (<)) is s)
-  then Just $ index (getLocation' sts is) arr
-  else Nothing
-indexNB {rep = Boxed o} is arr@(MkPABoxed sts _) =
-  if and (zipWith (delay .: (<)) is s)
-  then Just $ index (getLocation' sts is) arr
-  else Nothing
-indexNB {rep = Linked} is arr = (`Linked.index` arr) <$> checkRange s is
-indexNB {rep = Delayed} is arr = arr <$> checkRange s is
+indexUpdate : {rep,s : _} -> RepConstraint rep a => Coords s -> (a -> a) -> PrimArray rep s a -> PrimArray rep s a
+indexUpdate {rep = Bytes o} @{rc} is f arr@(MkPABytes sts _) =
+  let i = getLocation sts is
+  in create @{rc} s (\n => let x = index n arr in if n == i then f x else x)
+indexUpdate {rep = Boxed o} is f arr@(MkPABoxed sts _) =
+  let i = getLocation sts is
+  in create s (\n => let x = index n arr in if n == i then f x else x)
+indexUpdate {rep = Linked} is f arr = update is f arr
+indexUpdate {rep = Delayed} is f arr =
+  \is' =>
+    let x = arr is'
+    in if eqNP is is' then f x else x
+
+export
+indexRange : {rep,s : _} -> RepConstraint rep a => (rs : CoordsRange s) -> PrimArray rep s a
+              -> PrimArray rep (newShape rs) a
+indexRange {rep = Bytes o} @{rc} rs arr@(MkPABytes sts _) =
+  let s' : Vect ? Nat
+      s' = newShape rs
+      sts' := calcStrides o s'
+  in unsafeFromIns @{rc} (newShape rs) $
+        map (\(is,is') => (getLocation' sts' is',
+                            index (getLocation' sts is) arr))
+        $ getCoordsList rs
+indexRange {rep = Boxed o} rs arr@(MkPABoxed sts _) =
+  let s' : Vect ? Nat
+      s' = newShape rs
+      sts' := calcStrides o s'
+  in unsafeFromIns (newShape rs) $
+        map (\(is,is') => (getLocation' sts' is',
+                            index (getLocation' sts is) arr))
+        $ getCoordsList rs
+indexRange {rep = Linked} rs arr = Linked.indexRange rs arr
+indexRange {rep = Delayed} rs arr = Delayed.indexRange rs arr
+
+export
+indexSetRange : {rep,s : _} -> RepConstraint rep a => (rs : CoordsRange s)
+              -> PrimArray rep (newShape rs) a -> PrimArray rep s a -> PrimArray rep s a
+indexSetRange {rep = Bytes o} @{rc} rs rpl@(MkPABytes sts' _) arr@(MkPABytes sts _) =
+  unsafePerformIO $ do
+    let arr' = copy arr
+    unsafeDoIns @{rc} (map (\(is,is') =>
+      (getLocation' sts is, index (getLocation' sts' is') rpl))
+        $ getCoordsList rs) arr'
+    pure arr'
+indexSetRange {rep = Boxed o} rs rpl@(MkPABoxed sts' _) arr@(MkPABoxed sts _) =
+  unsafePerformIO $ do
+    let arr' = copy arr
+    unsafeDoIns (map (\(is,is') =>
+      (getLocation' sts is, index (getLocation' sts' is') rpl))
+        $ getCoordsList rs) arr'
+    pure arr'
+indexSetRange {rep = Linked} rs rpl arr = Linked.indexSetRange rs rpl arr
+indexSetRange {rep = Delayed} rs rpl arr = Delayed.indexSetRange rs rpl arr
 
 export
 indexUnsafe : {rep,s : _} -> RepConstraint rep a => Vect rk Nat -> PrimArray {rk} rep s a -> a
 indexUnsafe {rep = Bytes o} is arr@(MkPABytes sts _) = index (getLocation' sts is) arr
 indexUnsafe {rep = Boxed o} is arr@(MkPABoxed sts _) = index (getLocation' sts is) arr
-indexUnsafe {rep = Linked} is arr = assert_total $ case checkRange s is of
+indexUnsafe {rep = Linked} is arr = assert_total $ case validateCoords s is of
   Just is' => Linked.index is' arr
-indexUnsafe {rep = Delayed} is arr = assert_total $ case checkRange s is of
+indexUnsafe {rep = Delayed} is arr = assert_total $ case validateCoords s is of
   Just is' => arr is'
 
 export
@@ -100,3 +164,41 @@ convertRep {r1, r2} arr = fromFunction s (\is => PrimArray.index is arr)
 export
 fromVects : {rep : Rep} -> RepConstraint rep a => (s : Vect rk Nat) -> Vects s a -> PrimArray rep s a
 fromVects s v = convertRep {r1=Linked} v
+
+export
+fromList : {rep : Rep} -> LinearRep rep => RepConstraint rep a => (s : Vect rk Nat) -> List a -> PrimArray rep s a
+fromList {rep = (Boxed x)} = Boxed.fromList
+fromList {rep = (Bytes x)} = Bytes.fromList
+
+export
+mapPrim : {rep,s : _} -> RepConstraint rep a => RepConstraint rep b =>
+        (a -> b) -> PrimArray rep s a -> PrimArray rep s b
+mapPrim {rep = (Bytes x)} @{_} @{rc} f arr = Bytes.create @{rc} _ (\i => f $ Bytes.index i arr)
+mapPrim {rep = (Boxed x)} f arr = Boxed.create _ (\i => f $ Boxed.index i arr)
+mapPrim {rep = Linked} f arr = Linked.mapVects f arr
+mapPrim {rep = Delayed} f arr = f . arr
+
+
+export
+foldl : {rep,s : _} -> RepConstraint rep a => (b -> a -> b) -> b -> PrimArray rep s a -> b
+foldl {rep = Bytes _} = Bytes.foldl
+foldl {rep = Boxed _} = Boxed.foldl
+foldl {rep = Linked} = Linked.foldl
+foldl {rep = Delayed} = \f,z => Boxed.foldl f z . convertRep {r1=Delayed,r2=B}
+
+export
+foldr : {rep,s : _} -> RepConstraint rep a => (a -> b -> b) -> b -> PrimArray rep s a -> b
+foldr {rep = Bytes _} = Bytes.foldr
+foldr {rep = Boxed _} = Boxed.foldr
+foldr {rep = Linked} = Linked.foldr
+foldr {rep = Delayed} = \f,z => Boxed.foldr f z . convertRep {r1=Delayed,r2=B}
+
+export
+traverse : {rep,s : _} -> Applicative f => RepConstraint rep a => RepConstraint rep b =>
+            (a -> f b) -> PrimArray rep s a -> f (PrimArray rep s b)
+traverse {rep = Bytes o} = Bytes.traverse
+traverse {rep = Boxed o} = Boxed.traverse
+traverse {rep = Linked} = Linked.traverse
+traverse {rep = Delayed} = \f => map (convertRep @{()} @{()} {r1=B,r2=Delayed}) .
+                                  Boxed.traverse f .
+                                  convertRep @{()} @{()} {r1=Delayed,r2=B}
diff --git a/src/Data/NumIdr/PrimArray/Boxed.idr b/src/Data/NumIdr/PrimArray/Boxed.idr
index 9b038bd..54716d7 100644
--- a/src/Data/NumIdr/PrimArray/Boxed.idr
+++ b/src/Data/NumIdr/PrimArray/Boxed.idr
@@ -2,6 +2,7 @@ module Data.NumIdr.PrimArray.Boxed
 
 import Data.Buffer
 import System
+import Data.IORef
 import Data.IOArray.Prims
 import Data.Vect
 import Data.NumIdr.Array.Rep
@@ -108,6 +109,34 @@ fromList s xs = arrayAction s $ go xs 0
     go (x :: xs) i buf = arrayDataSet i x buf >> go xs (S i) buf
 
 
+export
+foldl : {s : _} -> (b -> a -> b) -> b -> PrimArrayBoxed o s a -> b
+foldl f z (MkPABoxed sts arr) =
+  if product s == 0 then z
+  else unsafePerformIO $ do
+    ref <- newIORef z
+    for_ [0..pred $ product s] $ \n => do
+        x <- readIORef ref
+        y <- arrayDataGet n arr
+        writeIORef ref (f x y)
+    readIORef ref
+
+export
+foldr : {s : _} -> (a -> b -> b) -> b -> PrimArrayBoxed o s a -> b
+foldr f z (MkPABoxed sts arr) =
+  if product s == 0 then z
+  else unsafePerformIO $ do
+    ref <- newIORef z
+    for_ [pred $ product s..0] $ \n => do
+         x <- arrayDataGet n arr
+         y <- readIORef ref
+         writeIORef ref (f x y)
+    readIORef ref
+
+export
+traverse : {o,s : _} -> Applicative f => (a -> f b) -> PrimArrayBoxed o s a -> f (PrimArrayBoxed o s b)
+traverse f = map (Boxed.fromList _) . traverse f . foldr (::) []
+
 {-
 export
 updateAt : Nat -> (a -> a) -> PrimArrayBoxed o s a -> PrimArrayBoxed o s a
@@ -145,10 +174,6 @@ fromList xs = create (length xs)
     fromJust : Maybe a -> a
     fromJust (Just x) = x
 
-||| Map a function over a primitive array.
-export
-map : (a -> b) -> PrimArrayBoxed a -> PrimArrayBoxed b
-map f arr = create (length arr) (\n => f $ index n arr)
 
 
 export
diff --git a/src/Data/NumIdr/PrimArray/Bytes.idr b/src/Data/NumIdr/PrimArray/Bytes.idr
index 4c0ce72..bd944f0 100644
--- a/src/Data/NumIdr/PrimArray/Bytes.idr
+++ b/src/Data/NumIdr/PrimArray/Bytes.idr
@@ -2,8 +2,6 @@ module Data.NumIdr.PrimArray.Bytes
 
 import System
 import Data.IORef
-import Data.Bits
-import Data.So
 import Data.Buffer
 import Data.Vect
 import Data.NumIdr.Array.Coords
@@ -12,160 +10,6 @@ import Data.NumIdr.Array.Rep
 %default total
 
 
-public export
-interface ByteRep a where
-  bytes : Nat
-
-  toBytes : a -> Vect bytes Bits8
-  fromBytes : Vect bytes Bits8 -> a
-
-export
-ByteRep Bits8 where
-  bytes = 1
-
-  toBytes x = [x]
-  fromBytes [x] = x
-
-export
-ByteRep Bits16 where
-  bytes = 2
-
-  toBytes x = [cast (x `shiftR` 8), cast x]
-  fromBytes [b1,b2] = cast b1 `shiftL` 8 .|. cast b2
-
-export
-ByteRep Bits32 where
-  bytes = 4
-
-  toBytes x = [cast (x `shiftR` 24),
-               cast (x `shiftR` 16),
-               cast (x `shiftR` 8),
-               cast x]
-  fromBytes [b1,b2,b3,b4] =
-    cast b1 `shiftL` 24 .|.
-    cast b2 `shiftL` 16 .|.
-    cast b3 `shiftL` 8 .|.
-    cast b4
-
-export
-ByteRep Bits64 where
-  bytes = 8
-
-  toBytes x = [cast (x `shiftR` 56),
-               cast (x `shiftR` 48),
-               cast (x `shiftR` 40),
-               cast (x `shiftR` 32),
-               cast (x `shiftR` 24),
-               cast (x `shiftR` 16),
-               cast (x `shiftR` 8),
-               cast x]
-  fromBytes [b1,b2,b3,b4,b5,b6,b7,b8] =
-    cast b1 `shiftL` 56 .|.
-    cast b2 `shiftL` 48 .|.
-    cast b3 `shiftL` 40 .|.
-    cast b4 `shiftL` 32 .|.
-    cast b5 `shiftL` 24 .|.
-    cast b6 `shiftL` 16 .|.
-    cast b7 `shiftL` 8 .|.
-    cast b8
-
-export
-ByteRep Int where
-  bytes = 8
-
-  toBytes x = [cast (x `shiftR` 56),
-               cast (x `shiftR` 48),
-               cast (x `shiftR` 40),
-               cast (x `shiftR` 32),
-               cast (x `shiftR` 24),
-               cast (x `shiftR` 16),
-               cast (x `shiftR` 8),
-               cast x]
-  fromBytes [b1,b2,b3,b4,b5,b6,b7,b8] =
-    cast b1 `shiftL` 56 .|.
-    cast b2 `shiftL` 48 .|.
-    cast b3 `shiftL` 40 .|.
-    cast b4 `shiftL` 32 .|.
-    cast b5 `shiftL` 24 .|.
-    cast b6 `shiftL` 16 .|.
-    cast b7 `shiftL` 8 .|.
-    cast b8
-
-export
-ByteRep Int8 where
-  bytes = 1
-
-  toBytes x = [cast x]
-  fromBytes [x] = cast x
-
-export
-ByteRep Int16 where
-  bytes = 2
-
-  toBytes x = [cast (x `shiftR` 8), cast x]
-  fromBytes [b1,b2] = cast b1 `shiftL` 8 .|. cast b2
-
-export
-ByteRep Int32 where
-  bytes = 4
-
-  toBytes x = [cast (x `shiftR` 24),
-               cast (x `shiftR` 16),
-               cast (x `shiftR` 8),
-               cast x]
-  fromBytes [b1,b2,b3,b4] =
-    cast b1 `shiftL` 24 .|.
-    cast b2 `shiftL` 16 .|.
-    cast b3 `shiftL` 8 .|.
-    cast b4
-
-export
-ByteRep Int64 where
-  bytes = 8
-
-  toBytes x = [cast (x `shiftR` 56),
-               cast (x `shiftR` 48),
-               cast (x `shiftR` 40),
-               cast (x `shiftR` 32),
-               cast (x `shiftR` 24),
-               cast (x `shiftR` 16),
-               cast (x `shiftR` 8),
-               cast x]
-  fromBytes [b1,b2,b3,b4,b5,b6,b7,b8] =
-    cast b1 `shiftL` 56 .|.
-    cast b2 `shiftL` 48 .|.
-    cast b3 `shiftL` 40 .|.
-    cast b4 `shiftL` 32 .|.
-    cast b5 `shiftL` 24 .|.
-    cast b6 `shiftL` 16 .|.
-    cast b7 `shiftL` 8 .|.
-    cast b8
-
-export
-ByteRep Bool where
-  bytes = 1
-
-  toBytes b = [if b then 1 else 0]
-  fromBytes [x] = x /= 0
-
-export
-ByteRep a => ByteRep b => ByteRep (a, b) where
-  bytes = bytes {a} + bytes {a=b}
-
-  toBytes (x,y) = toBytes x ++ toBytes y
-  fromBytes = bimap fromBytes fromBytes . splitAt _
-
-export
-{n : _} -> ByteRep a => ByteRep (Vect n a) where
-  bytes = n * bytes {a}
-
-  toBytes xs = concat $ map toBytes xs
-  fromBytes {n = 0} bs = []
-  fromBytes {n = S n} bs =
-    let (bs1, bs2) = splitAt _ bs
-    in  fromBytes bs1 :: fromBytes bs2
-
-
 export
 readBuffer : ByteRep a => (i : Nat) -> Buffer -> IO a
 readBuffer i buf = do
@@ -226,6 +70,15 @@ export
 index : ByteRep a => Nat -> PrimArrayBytes o s -> a
 index i (MkPABytes _ buf) = unsafePerformIO $ readBuffer i buf
 
+export
+copy : {o,s : _} -> PrimArrayBytes o s -> PrimArrayBytes o s
+copy (MkPABytes sts buf) =
+  MkPABytes sts (unsafePerformIO $ do
+    Just buf' <- newBuffer !(rawSize buf)
+      | Nothing => die "Cannot create array"
+    copyData buf 0 !(rawSize buf) buf' 0
+    pure buf)
+
 export
 reorder : {o,o',s : _} -> ByteRep a => PrimArrayBytes o s -> PrimArrayBytes o' s
 reorder @{br} arr@(MkPABytes sts buf) =
@@ -242,3 +95,31 @@ fromList @{br} s xs = bufferAction @{br} s $ go xs 0
     go : List a -> Nat -> Buffer -> IO ()
     go [] _ buf = pure ()
     go (x :: xs) i buf = writeBuffer i x buf >> go xs (S i) buf
+
+export
+foldl : {s : _} -> ByteRep a => (b -> a -> b) -> b -> PrimArrayBytes o s -> b
+foldl f z (MkPABytes sts buf) =
+  if product s == 0 then z
+  else unsafePerformIO $ do
+    ref <- newIORef z
+    for_ [0..pred $ product s] $ \n => do
+        x <- readIORef ref
+        y <- readBuffer n buf
+        writeIORef ref (f x y)
+    readIORef ref
+
+export
+foldr : {s : _} -> ByteRep a => (a -> b -> b) -> b -> PrimArrayBytes o s -> b
+foldr f z (MkPABytes sts buf) =
+  if product s == 0 then z
+  else unsafePerformIO $ do
+    ref <- newIORef z
+    for_ [pred $ product s..0] $ \n => do
+         x <- readBuffer n buf
+         y <- readIORef ref
+         writeIORef ref (f x y)
+    readIORef ref
+
+export
+traverse : {o,s : _} -> ByteRep a => ByteRep b => Applicative f => (a -> f b) -> PrimArrayBytes o s -> f (PrimArrayBytes o s)
+traverse f = map (Bytes.fromList _) . traverse f . foldr (::) []
diff --git a/src/Data/NumIdr/PrimArray/Delayed.idr b/src/Data/NumIdr/PrimArray/Delayed.idr
index c7a5825..96030e8 100644
--- a/src/Data/NumIdr/PrimArray/Delayed.idr
+++ b/src/Data/NumIdr/PrimArray/Delayed.idr
@@ -1,5 +1,6 @@
 module Data.NumIdr.PrimArray.Delayed
 
+import Data.List
 import Data.Vect
 import Data.NP
 import Data.NumIdr.Array.Rep
@@ -18,6 +19,20 @@ constant s x _ = x
 
 
 export
-checkRange : (s : Vect rk Nat) -> Vect rk Nat -> Maybe (Coords s)
-checkRange [] [] = Just []
-checkRange (d :: s) (i :: is) = (::) <$> natToFin i d <*> checkRange s is
+indexRange : {s : _} -> (rs : CoordsRange s) -> PrimArrayDelayed s a -> PrimArrayDelayed (newShape rs) a
+indexRange [] v = v
+indexRange (r :: rs) v with (cRangeToList r)
+  _ | Left i = indexRange rs (\is' => v (believe_me i :: is'))
+  _ | Right is = \(i::is') => indexRange rs (\is'' => v (believe_me (Vect.index i (fromList is)) :: is'')) is'
+
+export
+indexSetRange : {s : _} -> (rs : CoordsRange s) -> PrimArrayDelayed (newShape rs) a
+                  -> PrimArrayDelayed s a -> PrimArrayDelayed s a
+indexSetRange {s=[]} [] rv _ = rv
+indexSetRange {s=_::_} (r :: rs) rv v with (cRangeToList r)
+  _ | Left i = \(i'::is) => if i == finToNat i'
+                            then indexSetRange rs rv (v . (i'::)) is
+                            else v (i'::is)
+  _ | Right is = \(i'::is') => case findIndex (== finToNat i') is of
+    Just x => indexSetRange rs (rv . (x::)) (v . (i'::)) is'
+    Nothing => v (i'::is')
diff --git a/src/Data/NumIdr/PrimArray/Linked.idr b/src/Data/NumIdr/PrimArray/Linked.idr
index 54af7c0..2e9817e 100644
--- a/src/Data/NumIdr/PrimArray/Linked.idr
+++ b/src/Data/NumIdr/PrimArray/Linked.idr
@@ -1,6 +1,7 @@
 module Data.NumIdr.PrimArray.Linked
 
 import Data.Vect
+import Data.DPair
 import Data.NP
 import Data.NumIdr.Array.Rep
 import Data.NumIdr.Array.Coords
@@ -18,6 +19,25 @@ index : Coords s -> Vects s a -> a
 index [] x = x
 index (c :: cs) xs = index cs (index c xs)
 
+export
+update : Coords s -> (a -> a) -> Vects s a -> Vects s a
+update [] f v = f v
+update (i :: is) f v = updateAt i (update is f) v
+
+export
+indexRange : {s : _} -> (rs : CoordsRange s) -> Vects s a -> Vects (newShape rs) a
+indexRange [] v = v
+indexRange (r :: rs) v with (cRangeToList r)
+  _ | Left i = indexRange rs (Vect.index (believe_me i) v)
+  _ | Right is = believe_me $ map (\i => indexRange rs (Vect.index (believe_me i) v)) is
+
+export
+indexSetRange : {s : _} -> (rs : CoordsRange s) -> Vects (newShape rs) a -> Vects s a -> Vects s a
+indexSetRange {s=[]} [] rv _ = rv
+indexSetRange {s=_::_} (r :: rs) rv v with (cRangeToList r)
+  _ | Left i = updateAt (believe_me i) (indexSetRange rs rv) v
+  _ | Right is = foldl (\v,i => updateAt (believe_me i) (indexSetRange rs (Vect.index (believe_me i) rv)) v) v is
+
 
 export
 fromFunction : {s : _} -> (Coords s -> a) -> Vects s a
@@ -32,3 +52,23 @@ fromFunctionNB {s = d :: s} f = tabulate' {n=d} (\i => fromFunctionNB (f . (i::)
     tabulate' : forall a. {n : _} -> (Nat -> a) -> Vect n a
     tabulate' {n=Z} f = []
     tabulate' {n=S _} f = f Z :: tabulate' (f . S)
+
+export
+mapVects : {s : _} -> (a -> b) -> Vects s a -> Vects s b
+mapVects {s = []} f x = f x
+mapVects {s = _ :: _} f v = Prelude.map (mapVects f) v
+
+export
+foldl : {s : _} -> (b -> a -> b) -> b -> Vects s a -> b
+foldl {s=[]} f z v = f z v
+foldl {s=_::_} f z v = Prelude.foldl (Linked.foldl f) z v
+
+export
+foldr : {s : _} -> (a -> b -> b) -> b -> Vects s a -> b
+foldr {s=[]} f z v = f v z
+foldr {s=_::_} f z v = Prelude.foldr (flip $ Linked.foldr f) z v
+
+export
+traverse : {s : _} -> Applicative f => (a -> f b) -> Vects s a -> f (Vects s b)
+traverse {s=[]} f v = f v
+traverse {s=_::_} f v = Prelude.traverse (Linked.traverse f) v