/* Copyright (C) Eddie Edwards, 2000.  * All rights reserved worldwide. * * This software is provided "as is" without express or implied * warranties. You may freely copy and compile this source into * applications you distribute provided that the copyright text * below is included in the resulting source code, for example: * "Portions Copyright (C) Eddie Edwards, 2000" */// DifferentiableFunction.h//// abstract DifferentiableFunction class//// a DifferentiableFunction is a function object// which can be evaluated at any point, compared// with the zero function, and differentiated// Number//// this typedef defines the number field over which we// compute - this is primarily an easy way to switch from// float to double, but you could replace this with, say,// Complex, or the integers modulo a prime numbertypedef float	Number;class DifferentiableFunction{public:	virtual bool	IsZero() = 0;			// function is identically zero?	virtual Number	Evaluate(Number x) = 0;	// evaluate function at x	virtual void	Differentiate() = 0;};