from array update algorithm to nice Haskell code

[Wolfgang Jeltsch]

Hello,

I have an algorithm which updates one or more arrays in a loop.  The update 
operations depend on the (old) contents of the arrays, so I cannot use 
accumArray.  I want to implement this algorithm without mutable arrays in 
Haskell.  Are there any possibilities to do so efficiently?  Are there some 
hints about how to do this?

Wolfgang