3 files changed, 45 insertions, 3 deletions
diff --git a/src/Data/Array/Mixed.hs b/src/Data/Array/Mixed.hs
index 0351beb..d782e9f 100644
--- a/src/Data/Array/Mixed.hs
+++ b/src/Data/Array/Mixed.hs
@@ -211,6 +211,11 @@ ssxIotaFrom _ ZKSX = []
 ssxIotaFrom i (_ :!$@ ssh) = i : ssxIotaFrom (i+1) ssh
 ssxIotaFrom i (_ :!$? ssh) = i : ssxIotaFrom (i+1) ssh
 
+staticShapeFrom :: IShX sh -> StaticShX sh
+staticShapeFrom ZSX = ZKSX
+staticShapeFrom (n :$@ sh) = n :!$@ staticShapeFrom sh
+staticShapeFrom (_ :$? sh) = () :!$? staticShapeFrom sh
+
 lemRankApp :: StaticShX sh1 -> StaticShX sh2
            -> FromINat (Rank (sh1 ++ sh2)) :~: FromINat (Rank sh1) + FromINat (Rank sh2)
 lemRankApp _ _ = unsafeCoerce Refl  -- TODO improve this
@@ -414,3 +419,21 @@ slice ivs (XArray arr) = XArray (S.slice ivs arr)
 
 rev1 :: XArray (n : sh) a -> XArray (n : sh) a
 rev1 (XArray arr) = XArray (S.rev [0] arr)
+
+-- | Throws if the given array and the target shape do not have the same number of elements.
+reshape :: forall sh1 sh2 a. Storable a => StaticShX sh1 -> IShX sh2 -> XArray sh1 a -> XArray sh2 a
+reshape ssh1 sh2 (XArray arr)
+  | Dict <- lemKnownINatRankSSX ssh1
+  , Dict <- knownNatFromINat (Proxy @(Rank sh1))
+  , Dict <- lemKnownINatRank sh2
+  , Dict <- knownNatFromINat (Proxy @(Rank sh2))
+  = XArray (S.reshape (shapeLshape sh2) arr)
+
+-- | Throws if the given array and the target shape do not have the same number of elements.
+reshapePartial :: forall sh1 sh2 sh' a. Storable a => StaticShX sh1 -> StaticShX sh' -> IShX sh2 -> XArray (sh1 ++ sh') a -> XArray (sh2 ++ sh') a
+reshapePartial ssh1 ssh' sh2 (XArray arr)
+  | Dict <- lemKnownINatRankSSX (ssxAppend ssh1 ssh')
+  , Dict <- knownNatFromINat (Proxy @(Rank (sh1 ++ sh')))
+  , Dict <- lemKnownINatRankSSX (ssxAppend (staticShapeFrom sh2) ssh')
+  , Dict <- knownNatFromINat (Proxy @(Rank (sh2 ++ sh')))
+  = XArray (S.reshape (shapeLshape sh2 ++ drop (length sh2) (S.shapeL arr)) arr)
diff --git a/src/Data/Array/Nested.hs b/src/Data/Array/Nested.hs
index ec5f0b5..c7d1819 100644
--- a/src/Data/Array/Nested.hs
+++ b/src/Data/Array/Nested.hs
@@ -9,7 +9,7 @@ module Data.Array.Nested (
   rshape, rindex, rindexPartial, rgenerate, rsumOuter1,
   rtranspose, rappend, rscalar, rfromVector, rtoVector, runScalar,
   rconstant, rfromList, rfromList1, rtoList, rtoList1,
-  rslice, rrev1,
+  rslice, rrev1, rreshape,
   -- ** Lifting orthotope operations to 'Ranked' arrays
   rlift,
 
@@ -21,7 +21,7 @@ module Data.Array.Nested (
   sshape, sindex, sindexPartial, sgenerate, ssumOuter1,
   stranspose, sappend, sscalar, sfromVector, stoVector, sunScalar,
   sconstant, sfromList, sfromList1, stoList, stoList1,
-  sslice, srev1,
+  sslice, srev1, sreshape,
   -- ** Lifting orthotope operations to 'Shaped' arrays
   slift,
 
@@ -30,7 +30,7 @@ module Data.Array.Nested (
   IxX(..), IIxX,
   KnownShapeX(..), StaticShX(..),
   mgenerate, mtranspose, mappend, mfromVector, mtoVector, munScalar,
-  mconstant, mfromList, mtoList, mslice, mrev1,
+  mconstant, mfromList, mtoList, mslice, mrev1, mreshape,
 
   -- * Array elements
   Elt(mshape, mindex, mindexPartial, mscalar, mfromList1, mtoList1, mlift, mlift2),
diff --git a/src/Data/Array/Nested/Internal.hs b/src/Data/Array/Nested/Internal.hs
index 350eb6f..d041aff 100644
--- a/src/Data/Array/Nested/Internal.hs
+++ b/src/Data/Array/Nested/Internal.hs
@@ -540,6 +540,11 @@ mslice ivs = mlift $ \_ -> X.slice ivs
 mrev1 :: (KnownShapeX (n : sh), Elt a) => Mixed (n : sh) a -> Mixed (n : sh) a
 mrev1 = mlift $ \_ -> X.rev1
 
+mreshape :: forall sh sh' a. (KnownShapeX sh, KnownShapeX sh', Elt a)
+         => IShX sh' -> Mixed sh a -> Mixed sh' a
+mreshape sh' = mlift $ \(_ :: Proxy shIn) ->
+                        X.reshapePartial (knownShapeX @sh) (knownShapeX @shIn) sh'
+
 mliftPrim :: (KnownShapeX sh, Storable a)
           => (a -> a)
           -> Mixed sh (Primitive a) -> Mixed sh (Primitive a)
@@ -1083,6 +1088,13 @@ rslice ivs = rlift $ \_ -> X.slice ivs
 rrev1 :: (KnownINat n, Elt a) => Ranked (S n) a -> Ranked (S n) a
 rrev1 = rlift $ \_ -> X.rev1
 
+rreshape :: forall n n' a. (KnownINat n, KnownINat n', Elt a)
+         => IShR n' -> Ranked n a -> Ranked n' a
+rreshape sh' (Ranked arr)
+  | Dict <- lemKnownReplicate (Proxy @n)
+  , Dict <- lemKnownReplicate (Proxy @n')
+  = Ranked (mreshape (shCvtRX sh') arr)
+
 
 -- ====== API OF SHAPED ARRAYS ====== --
 
@@ -1292,3 +1304,10 @@ sslice ivs = slift $ \_ -> X.slice ivs
 
 srev1 :: (KnownNat n, KnownShape sh, Elt a) => Shaped (n : sh) a -> Shaped (n : sh) a
 srev1 = slift $ \_ -> X.rev1
+
+sreshape :: forall sh sh' a. (KnownShape sh, KnownShape sh', Elt a)
+         => ShS sh' -> Shaped sh a -> Shaped sh' a
+sreshape sh' (Shaped arr)
+  | Dict <- lemKnownMapJust (Proxy @sh)
+  , Dict <- lemKnownMapJust (Proxy @sh')
+  = Shaped (mreshape (shCvtSX sh') arr)