Set SpecialFunctions compat and fix deprecations

Author: devmotion

Project.toml

@@ -15,7 +15,7 @@ ZygoteRules = "700de1a5-db45-46bc-99cf-38207098b444"
 Compat = "2.2"
 Distances = "0.8"
 PDMats = "0.9"
-SpecialFunctions = "0"
+SpecialFunctions = "0.9"
 StatsFuns = "0.8"
 ZygoteRules = "0.2"
 julia = "1.0"

src/KernelFunctions.jl

@@ -16,7 +16,7 @@ export Transform, SelectTransform, ChainTransform, ScaleTransform, LowRankTransf
 
 using Compat
 using Distances, LinearAlgebra
-using SpecialFunctions: lgamma, besselk
+using SpecialFunctions: logabsgamma, besselk
 using ZygoteRules: @adjoint
 using StatsFuns: logtwo
 using PDMats: PDMat

src/kernels/matern.jl

@@ -33,7 +33,7 @@ end
 params(k::MaternKernel) = (params(transform(k)),k.ν)
 opt_params(k::MaternKernel) = (opt_params(transform(k)),k.ν)
 
-@inline kappa(κ::MaternKernel, d::Real) = iszero(d) ? one(d) : exp((1.0-κ.ν)*logtwo-lgamma(κ.ν) + κ.ν*log(sqrt(2κ.ν)*d)+log(besselk(κ.ν,sqrt(2κ.ν)*d)))
+@inline kappa(κ::MaternKernel, d::Real) = iszero(d) ? one(d) : exp((1.0-κ.ν)*logtwo-logabsgamma(κ.ν)[1] + κ.ν*log(sqrt(2κ.ν)*d)+log(besselk(κ.ν,sqrt(2κ.ν)*d)))
 
 """
 `Matern32Kernel([ρ=1.0])`