[AndrewJ]

Gday Freddy

"If you want to modify just the red portion, then break it in 3: first and third curves from a lookup table, the second (red) is a linear function ds/dt = constant".

Brilliantly simple and doable http://www.iceinspace.com.au/forum/....es/happy04.gif.

Another thing to look at is whether parts 1 and 3 of the function
are symmetric.
If so, you can use just one lookup table and hence crib some space or expand the resolution of the tails.

Andrew