[e, ix] = min(X);

min x = z $ foldl' f (e,0,0) es
  where
    (e:es) = toList x
    f (a,ix,r) b = let ix' = ix+1 in if a < b then (a,ix',r) else (b,ix',ix')
    z (a,ix,r) = (a,r)

min x = traverse x to0D min
  where
    to0D (Z:.i) = Z
    min f (Z) = ??? -- how to get elements for comparison?

[f (Z:.i) | i <- [1..n]], where n = ((Z:.i) -> i) $ extent x

import Data.Array.Repa

indexed arr = traverse arr id (src idx@(Z :. i) -> (src idx, i))

minimize arr = foldP f h t
  where
    (Z :. n) = extent arr
    arr' = indexed arr
    h = arr' ! (Z :. 0)
    t = extract (Z :. 1) (Z :. (n-1)) arr'
    f min@(valMin, iMin) x@(val, i) | val < valMin = x
                                    | otherwise = min

{-# LANGUAGE TypeOperators, FlexibleContexts #-}
import Data.Array.Repa

idx :: Int -> (Z :. Int)
idx n = Z :. n

(//) :: Source U e => Array U (Z :. Int) e -> Int -> e
(//) v n = v ! (idx n)

min' n v = m 0
  where m p | p == n - 1 = (v // p, p)
            | True       = if x < x' then (x, p) else (x', p')
                           where (x', p') = m (p + 1)
                                 x = v // p

v2 :: Array U (Z :. Int) Int
v2 = fromListUnboxed (idx 6) [7, 2, 9, 3, 0, 5]

example = min' 6 v2
-- OUT: (0, 4)