XLPack 7.0
XLPack Numerical Library (C API) Reference Manual
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◆ jacobi()

double jacobi ( unsigned int  n,
double  alpha,
double  beta,
double  x 
)

Jacobi polynomial Pn(α, β)(x)

Purpose
This function computes the Jacobi polynomial.
The Jacobian polynomial Pn(α, β)(x) is an orthogonal polynomial defined on the interval [-1, 1] with a weight function w(x) = (1 - x)^α (1 + x)^β.
The Jacobi polynomial satisfies the following three term recurrence relation.
P0(α, β)(x) = 1
P1(α, β)(x) = (1/2)((α + β + 2)x + (α - β))
Pn(α, β)(x) = (1/(2n(n + α + β)(2n + α + β - 2)))((2n + α + β - 1)((2n + α + β - 2)(2n + α + β)x + (α^2 - β^2))P(n - 1)(α, β)(x) - 2(n + α - 1)(n + β - 1)(2n + α + β)P(n - 2)(α, β)(x))
Returns
Jacobi polynomial Pn(α, β)(x).
Parameters
[in]nDegree of polynomial n. (n >= 0)
[in]alphaParameter α.
[in]betaParameter β.
[in]xArgument x.
Error handling
  • Range error (ERANGE) may be reported.
Reference
boost/math/special_functions