ApproxFunOrthogonalPolynomials.Arc
— TypeArc(c,r,(θ₁,θ₂))
represents the arc centred at c
with radius r
from angle θ₁
to θ₂
.
ApproxFunOrthogonalPolynomials.Chebyshev
— TypeChebyshev()
is the space spanned by the Chebyshev polynomials
T_0(x),T_1(x),T_2(x),…
where T_k(x) = cos(k*acos(x))
. This is the default space as there exists a fast transform and general smooth functions on [-1,1]
can be easily resolved.
ApproxFunOrthogonalPolynomials.GaussWeight
— MethodGaussWeight(Hermite(L), L)
is a space spanned by exp(-Lx²) * H_k(sqrt(L) * x)
where H_k(x)
's are Hermite polynomials.
GaussWeight()
is equivalent to GaussWeight(Hermite(), 1.0)
by default.
ApproxFunOrthogonalPolynomials.Hermite
— TypeHermite(L)
represents H_k(sqrt(L) * x)
where H_k
are Hermite polynomials. Hermite()
is equivalent to Hermite(1.0)
.
ApproxFunOrthogonalPolynomials.Jacobi
— TypeJacobi(b,a)
represents the space spanned by Jacobi polynomials P_k^{(a,b)}
, which are orthogonal with respect to the weight (1+x)^β*(1-x)^α
ApproxFunOrthogonalPolynomials.Laguerre
— TypeLaguerre(α)
is a space spanned by generalized Laguerre polynomials Lₙᵅ(x)
's on (0, Inf)
, which satisfy the differential equations
xy'' + (α + 1 - x)y' + ny = 0
Laguerre()
is equivalent to Laguerre(0)
by default.
ApproxFunOrthogonalPolynomials.LaguerreWeight
— TypeLaguerreWeight(α, L, space)
weights space
by x^α * exp(-L*x)
.
ApproxFunOrthogonalPolynomials.LaguerreWeight
— MethodLaguerreWeight(α, space)
weights space
by x^α * exp(-x)
.
ApproxFunOrthogonalPolynomials.Line
— TypeLine{a}(c)
represents the line at angle a
in the complex plane, centred at c
.
ApproxFunOrthogonalPolynomials.Ray
— TypeRay{a}(c,L,o)
represents a scaled ray (with scale factor L) at angle a
starting at c
, with orientation out to infinity (o = true
) or back from infinity (o = false
).
ApproxFunOrthogonalPolynomials.Ultraspherical
— TypeUltraspherical(λ)
is the space spanned by the ultraspherical polynomials
C_0^{(λ)}(x),C_1^{(λ)}(x),C_2^{(λ)}(x),…
Note that λ=1
this reduces to Chebyshev polynomials of the second kind: C_k^{(1)}(x) = U_k(x)
. For λ=1/2
this also reduces to Legendre polynomials: C_k^{(1/2)}(x) = P_k(x)
.
ApproxFunOrthogonalPolynomials.WeightedLaguerre
— MethodWeightedLaguerre(α)
is the weighted generalized Laguerre space x^αexp(-x)L_k^(α)(x).
ApproxFunOrthogonalPolynomials.WeightedLaguerre
— MethodWeightedLaguerre()
is the weighted Laguerre space exp(-x)*L_k(x).