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<HTML>
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<TITLE>TSP (libtsp/FN) - FNevChebP</TITLE>
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<BODY BGCOLOR="#FFFACD">
<H2>FNevChebP</H2>
<HR>
<H4>Routine</H4>
<DL>
<DT>
double FNevChebP (double x, const float c[], int N)
</DL>
<H4>Purpose</H4>
<DL>
<DT>
Evaluate a series expansion in Chebyshev polynomials
</DL>
<H4>Description</H4>
The series expansion in Chebyshev polynomials is defined as
<P>
<PRE>
N-1
Y(x) = SUM c(i) T(i,x) ,
i=0
</PRE>
<P>
where N is the number of terms in the expansion, c(i) is the coefficient for
the i'th Chebyshev polynomial, and T(i,x) is the i'th order Chebyshev
polynomial evaluated at x.
<P>
The Chebyshev polynomials satisfy the recursion
<PRE>
T(i,x) = 2x T(i-1,x) - T(i-2,x),
</PRE>
with the initial conditions T(0,x)=1 and T(1,x)=x. This routine evaluates
the expansion using a backward recursion.
<H4>Parameters</H4>
<DL>
<DT>
<- double FNevChebP
<DD>
Resultant value
<DT>
-> double x
<DD>
Input value
<DT>
-> const float c[]
<DD>
Array of coefficient values. c[i] is the coefficient of the i'th order
Chebyshev polynomial.
<DT>
-> int N
<DD>
Number of coefficients
</DL>
<H4>Author / revision</H4>
P. Kabal Copyright (C) 1997
/ Revision 1.11 1997/10/14
<P>
<HR>
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