Repeated function evaluation?

*To*: mathgroup at smc.vnet.net*Subject*: [mg24240] Repeated function evaluation?*From*: AES <siegman at stanford.edu>*Date*: Mon, 3 Jul 2000 20:39:21 -0400 (EDT)*Organization*: Stanford University*Sender*: owner-wri-mathgroup at wolfram.com

Suppose I have a function f[x_,y_] := Module[{ }, . . .] where the module is fairly time-consuming to evaluate. If I call this function a second time in a given notebook using identical values of the arguments x and y , is Mathematica smart enough the second time around to recognize that it's already evaluated the function once for those arguments, and use a stored value? Or, if I want to use the values of this function for a given range of arguments multiple times (e.g., replotting the values in different ways), do I need to do something like Do[ ff[x,y] = f[x,y], {x, x1, x2}, {y, y1, y2} ] and use the values ff[x,y] instead? Thanks AES