Re: Efficiency of list indices in definitions

A large part of what I'm looking for at the moment is simply to find a fast and efficient way to express cyclic graphs in Haskell because in a present research project I need to manipulate machines with hundreds and thousands of states and my current, simple implementation simply won't do: my jobs balloon in size and die. At the same time, code written and run in the early eighties outperforms mine!! (Blushing with shame.) Basically, I'm trying to find out whether Haskell is inherently that much slower or whether I am simply not yet quite competent enough to approach the problem correctly.

Have you looked at the Functional Graph Library by Martin Erwig? http://www.cs.orst.edu/~erwig/fgl/haskell/ Tom