f(x), x E [-1,1] is given by the following appproximation formula in terms of Chebyshev polynomials:
f(x) = (1/2)*c_0*T_0(x) + ... + c_n*T_n(x)
Given the vector of coefficients, c(0), ..., c(n), this routine evaluates the above sum at a point x E [-1,1].
Clenshaw recursion formula is used to evaluate the sum.
Reference
William Press, Brian Flannery, Saul Teukolsky, William Vetterling, Numerical Recipes in FORTRAN: The Art of Scientific Computing, Second Edition, Cambridge University Press, 1992, Page: 185--187
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| integer, | intent(in) | :: | n |
Highest degree of T_n (x). |
||
| real(kind=rp), | intent(in), | dimension(0:n) | :: | c |
Chebyshev coefficients |
|
| real(kind=rp), | intent(in) | :: | x |
x E [-1,1] the point where the sum is to be evaluated. |