"Biff" wrote...
....
I've always wondered why some functions are volatile. I can understand
why a couple are, Now, Today, but why the others?

Rand, Randbetween, Indirect, Offset
....

RAND[BETWEEN] needs to be volatile for the same reason NOW does. It *should*
change value on *every* recalc.

As for INDIRECT, it'd be awkward and inefficient to try to figure out its
own dependencies and the dependencies it induces. If it were passed a
constant array, e.g., ROW(INDIRECT("1:1024")), then it could be nonvolatile,
but that's an unreasonable level of semantic overloading.

As for OFFSET, better point since volatile OFFSET(r,a,b,c,d) is presumably
equivalent to nonvolatile INDEX(r,a+1,b+1):INDEX(r,a+c,b+d),
at least if one can rely on INDEX being nonvolatile.