Interpolation with random nodes

*To*: mathgroup at smc.vnet.net*Subject*: [mg44754] Interpolation with random nodes*From*: "Wojtek" <a_d_u_n at o2.pl>*Date*: Tue, 25 Nov 2003 00:45:22 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Hello, I want to interpolate function with a few different sets of nodes. One of them are random ones. I have made the list of nodes and my function's values: (n is given) data1=Table[{e=Random[]*2-1,ArcTan(x,0.,n}] and I have a list: {{x_0,f(x_0)},{x_1,f(x_1)}...} I use the following formula to calculate my function L(x) = SUM(j=0..n) f(x_j) * Lambda(j,x) And I need to extract these values from my list. and I want to define two functions y[n] - this returns the f(x_n) from my list x[n] - this returns the x_n from my list how can I do it in mathematica? Thank you for any help Wojtek