Internal
PSIS.GeneralizedPareto
— TypeGeneralizedPareto{T<:Real}
The generalized Pareto distribution.
Constructor
GeneralizedPareto(μ, σ, k)
Construct the generalized Pareto distribution (GPD) with location parameter $μ$, scale parameter $σ$ and shape parameter $k$.
The shape parameter $k$ is equivalent to the commonly used shape parameter $ξ$. This is the same parameterization used by Vehtari et al. [1] and is related to that used by Zhang and Stephens [2] as $k \mapsto -k$.
PSIS.fit_gpd
— Methodfit_gpd(x; μ=0, kwargs...)
Fit a GeneralizedPareto
with location μ
to the data x
.
The fit is performed using the Empirical Bayes method of Zhang and Stephens [2].
Keywords
prior_adjusted::Bool=true
, Iftrue
, a weakly informative Normal prior centered on $\frac{1}{2}$ is used for the shape $k$.sorted::Bool=issorted(x)
: Iftrue
,x
is assumed to be sorted. Iffalse
, a sorted copy ofx
is made.min_points::Int=30
: The minimum number of quadrature points to use when estimating the posterior mean of $\theta = \frac{\xi}{\sigma}$.
References
- [2] Zhang & Stephens, Technometrics 51:3 (2009)