gprnd
Generalized Pareto random numbers
Syntax
r = gprnd(k,sigma,theta)
r = gprnd(k,sigma,theta,m,n,...)
R = gprnd(K,sigma,theta,[m,n,...])
Description
r = gprnd(k,sigma,theta)
returns an array of random numbers chosen from the generalized Pareto (GP) distribution with tail index (shape) parameterk
, scale parametersigma
, and threshold (location) parameter,theta
. The size ofr
is the common size of the input arguments if all are arrays. If any parameter is a scalar, the size ofr
is the size of the other parameters.
r = gprnd(k,sigma,theta,m,n,...)
orR = gprnd(K,sigma,theta,[m,n,...])
generates anm
-by-n
-by-... array. Thek
,sigma
,theta
parameters can each be scalars or arrays of the same size asr
.
Whenk = 0
andtheta = 0
, the GP is equivalent to the exponential distribution. Whenk > 0
andtheta = sigma/k
, the GP is equivalent to a Pareto distribution with a scale parameter equal tosigma/k
and a shape parameter equal to1/k
. The mean of the GP is not finite whenk
≥1
, and the variance is not finite whenk
≥1/2
. Whenk
≥0
, the GP has positive density for
x > theta
, or, when
References
[1] Embrechts, P., C. Klüppelberg, and T. Mikosch.Modelling Extremal Events for Insurance and Finance. New York: Springer, 1997.
[2] Kotz, S., and S. Nadarajah.Extreme Value Distributions: Theory and Applications. London: Imperial College Press, 2000.