Paul Abbott Chebyshev Article
- To: mathgroup at smc.vnet.net
- Subject: [mg79699] Paul Abbott Chebyshev Article
- From: Angela Kou <Akou at lbl.gov>
- Date: Thu, 2 Aug 2007 03:48:13 -0400 (EDT)
Hi: I'm trying to test Paul Abbott's code in his article on integral equation solving using Chebyshev polynomials (Mathematica Journal 8(4)) but Mathematica keeps giving me an error when I get to NIntegrate. This is the code: n=4; xs = N[Cos[Range[0, 2 n] Pi/(2 n)], 20]; cs = Thread[Subscript[c, Range[0, n]]]; lhs = cs.Table[Subscript[T, 2 i] (xs), {i, 0, n}]; rhs = 1 + 1/Pi cs.Table[NIntegrate[Evaluate[Subscript[T, 2 i] (t)/((xs - t)^2 + 1)], {t, -1, 1}, WorkingPrecision ->20], {i, 0, n}]; the last line of code keeps giving me the error that "NIntegrate::inumr: The integrand (t Subscript[T,0])/(1+(1.0000000000000000000-t)^2) has evaluated to non-numerical values for all sampling points in the region with boundaries {{-1,0}}. >> I'm not quite sure why this is the case? Thanks, Angela Kou