[Haskell-cafe] Transpose using array comprehension

[Henning Thielemann]

On Wed, 18 Apr 2007, Chris Witte wrote:

> I just started playing around with GHC.PArr and array comprehension
> and I was wondering if there is a way to define the transpose of a
> matrix using array comprehension?

Why not

  let swap :: (i,j) -> (j,i)
      swap (a,b) = (b,a)
  in  ixmap (let (lower,upper) = bounds arr in (swap lower, swap upper))
            swap arr

?