Derivative of InterpolatingFunction

*To*: mathgroup at smc.vnet.net*Subject*: [mg4344] Derivative of InterpolatingFunction*From*: Andrei Constantinescu <constant at athena.polytechnique.fr>*Date*: Thu, 11 Jul 1996 00:59:50 -0400*Sender*: owner-wri-mathgroup at wolfram.com

I have the following problem: fct = InterpolatingFunction[{{0., 3.14159}, {0., 3.14159}}, <>] ... so its an InterpolatingFunction of 2 variables . What I want now to do is the derivative of this function. But I fail ! I get for example: In[69]:= Derivative[1,0][fct] (1,0) Out[69]= (InterpolatingFunction[{{25., 210.}, {0., 17.}}, <>]) In[71]:= %69[100., 4.] (1,0) Out[71]= (InterpolatingFunction[{{25., 210.}, {0., 17.}}, <>]) [100., 4.] which is of no practical use as you see ! However the same procedure functions if the InterpolatingFunction has just one variable. I guess its realted to the function definition, but I do not see how to fix it. Any help is welcome ! Thanks ! a + andrei ______________________________________________________________________ Andrei Constantinescu constant at athena.polytechnique.fr LMS Ecole Polytechnique tel: (33)-1-69.33.33.30 91128 PALAISEAU cedex - FRANCE fax: (33)-1-69.33.30.26 ==== [MESSAGE SEPARATOR] ====