[mrkeen]

> My question for Haskellers is how to do updates of values on a large scale, let's say in a simulation.

The same way games do it. The whole world, one frame at a time. If you are simulating objects affected by gravity, you do not recalculate the position of each item in-place before moving onto the next item. You figure out all the new accelerations, velocities and positions, and then apply them all.