gppdf
Generalized Pareto probability density function
Syntax
p = gppdf(x,k,sigma,theta)
Description
p = gppdf(x,k,sigma,theta)
returns
the pdf of the generalized Pareto (GP) distribution with the tail
index (shape) parameter k
, scale parameter sigma
,
and threshold (location) parameter, theta
, evaluated
at the values in x
. The size of p
is
the common size of the input arguments. A scalar input functions
as a constant matrix of the same size as the other inputs.
Default values for k
, sigma
,
and theta
are 0, 1, and 0, respectively.
When k = 0
and theta = 0
,
the GP is equivalent to the exponential distribution. When k
> 0
and theta = sigma/k
, the GP is
equivalent to a Pareto distribution with a scale parameter equal to sigma/k
and
a shape parameter equal to 1/k
. The mean of the
GP is not finite when k
≥ 1
,
and the variance is not finite when k
≥ 1/2
.
When k
≥ 0
, the GP has
positive density for
x > theta
, or, when
k < 0
, .
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.
Extended Capabilities
Version History
Introduced before R2006a