Hello. How can I multiply matrices (of Doubles) with dph (-0.4.0)? (ghc-6.12.1) - I was trying type Vector = [:Double:] type Matrix = [:Vector:] times :: Matrix -> Matrix -> Matrix times a b = mapP ( \ row -> mapP ( \ col -> sumP ( zipWithP (*) row col ) ) ( transposeP b ) ) a but there is no such thing as transposeP. When I try any kind of index manipulations, the compiler invariably tells me that it does not want to build [: :] - lists of indices (e.g., there is no enumFromToP) (I guess because I'm using Data.Array.Parallel.Prelude.Double) Puzzled - J.W. PS: what's the recommended way to multiply matrices (better modelled as Array (Int,Int) Double or [[Double]] ?) with the par/pseq approach (if this is recommended at all)? As I said earlier, I just want to have some nice and easy benchmarks for demonstration in a lecture (to be run on 2, 4, or 8 cores). Of course if they work, I'd use them in real life as well...