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# Implementing math functions

Posted on 1998-04-28

Hi All

I would like some ideas on how to get Delphi to evaluate mathematical functions. Suppose I define a function f(x) = x^2. I would like to 'send' f(2) and get 4 back. Now, this is harder then it would seem, because I need to implement _user-defined_ functions at runtime. The user will be able to define a function, say, Sqrt(E^(2*x) + Ln(4*Pi) - log(23*x^3)), in a TEdit, and I have to manipulate the result of the function over a given interval, for many, many values.

Yes, I know of the Poly function, but one of my main problems is that even if I succeeded in translating a function into Delphi using the arithmetic routines, I don't know how I could store the function so that I don't need to keep _re-translating_ it for each iteration. E.G. If the user defined x^2, and I need to calculate x^2 for 2500 values, how can I store the function as an object so that I don't keep translating what is in the TEdit into a function, replacing my x-value, and re-calculating?

Those of you who program in Java may know of the Function method, where you can assign a veritable beast, and evaluate the funtion at given points. I need a Delphi equivalent, or a component (which I have looked for), or a new way of thinking about a solution.

Many thanks if you've read this far :)

Edo