(m - es)^2/es

let res = listMatrix (shape m) [ (o-e)^2 / e | o <- colElems m | e <- colElems es ] where colElems = concatMap elems . cols res

Hi Cetin, This is probably the easiest way: listMatrix (2,2) [0.6163270413689804,0.600918865334756,0.33217626255600896,0.3238718559921087 ] This will create 2 temporary arrays. Alternatively, listMatrix (2,2) [0.6163270413689804,0.600918865334756,0.33217626255600896,0.3238718559921087 ] In a later version of the library, "colElems" will probably be built- in. This version has the disadvantage that it doesn't use BLAS calls. If you *really* want to get tricky and eliminate temporary arrays:

runSTMatrix $ do res <- newCopyMatrix m subMatrix res es modifyWith (^2) res divMatrix res es return res

Now, to get the sum:

sumAbs $ vectorFromMatrix res 1.8732940252518542

or

sum $ elems res 1.8732940252518542

The first version will usually be more efficient, since it calls the BLAS1 function "dasum". Patrick