Re: Numerical Differentiation

*To*: mathgroup at smc.vnet.net*Subject*: [mg4291] Re: Numerical Differentiation*From*: Paul Abbott <paul at earwax.pd.uwa.edu.au>*Date*: Sat, 29 Jun 1996 03:55:33 -0400*Organization*: University of Western Australia*Sender*: owner-wri-mathgroup at wolfram.com

Mark James wrote: > Does anyone know of a function that calculates the derivative of > a function (that can't be differentiated symbolically) Why can't it be differentiated symbolically? > at a given > point by numerical means? I can't find it as a built-in or in the > standard packages. Thanks. There is the ND function in NumericalMath`NLimit`. Another way of proceeding is to sample the function at a number of points, interpolate, and then differentiate: points = Table[{x,f[x]}, {x,0,1,0.1}]; fint = Interpolate[points]; fint'[0.3] This also works with partial derivatives (if you get the DInterpolatingFunction.m package mentioned in the Mathematica Journal 4(2):31). Cheers, Paul _________________________________________________________________ Paul Abbott Department of Physics Phone: +61-9-380-2734 The University of Western Australia Fax: +61-9-380-1014 Nedlands WA 6907 paul at physics.uwa.edu.au AUSTRALIA http://www.pd.uwa.edu.au/Paul _________________________________________________________________ ==== [MESSAGE SEPARATOR] ====