1 files changed, 21 insertions, 0 deletions
diff --git a/third_party/bazel/rules_haskell/examples/vector/benchmarks/Algo/ListRank.hs b/third_party/bazel/rules_haskell/examples/vector/benchmarks/Algo/ListRank.hs
new file mode 100644
index 0000000000..933bd8eb2e
--- /dev/null
+++ b/third_party/bazel/rules_haskell/examples/vector/benchmarks/Algo/ListRank.hs
@@ -0,0 +1,21 @@
+module Algo.ListRank
+where
+
+import Data.Vector.Unboxed as V
+
+listRank :: Int -> Vector Int
+{-# NOINLINE listRank #-}
+listRank n = pointer_jump xs val
+  where
+    xs = 0 `V.cons` V.enumFromTo 0 (n-2)
+
+    val = V.zipWith (\i j -> if i == j then 0 else 1)
+                    xs (V.enumFromTo 0 (n-1))
+
+    pointer_jump pt val
+      | npt == pt = val
+      | otherwise = pointer_jump npt nval
+      where
+        npt  = V.backpermute pt pt
+        nval = V.zipWith (+) val (V.backpermute val pt)
+