ecld-class {ldhmm}R Documentation

An S4 class to represent the lambda distribution

Description

The ecld class serves as an object-oriented interface for the lambda distribution, which is just the exponential power distribution in GSL and Wolfram.

Slots

call

the match.call slot

lambda

numeric

sigma

numeric

mu

numeric

Details

The lambda distribution is just the exponential power distribution in GSL and Wolfram, with a different definition in the exponent of the stretched exponential function.

The distribution is symmetric. Its PDF is

P\left(x; \lambda, \sigma, \mu\right) \equiv\, \frac{1}{\lambda \Gamma\left(\frac{2}{\lambda}\right) \sigma} e^{-{\left|\frac{x-\mu}{\sigma}\right|}^{\frac{2}{\lambda}}}.

where \lambda is the shape parameter, \sigma is the scale parameter, \mu is the location parameter.
This functional form is not unfamiliar and has appeared under several other names, such as generalized normal distribution and power exponential distribution, etc..

Author(s)

Stephen H. Lihn

References

This distribution is the same as gnorm and is implemented from it since V0.6. See https://cran.r-project.org/package=gnorm.
For lambda distribution and option pricing model, see Stephen Lihn (2015). The Special Elliptic Option Pricing Model and Volatility Smile. SSRN: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2707810.
Closed form solutions are derived in Stephen Lihn (2016). Closed Form Solution and Term Structure for SPX Options. SSRN: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2805769 and
Stephen Lihn (2017). From Volatility Smile to Risk Neutral Probability and Closed Form Solution of Local Volatility Function. SSRN: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2906522


[Package ldhmm version 0.6.1 Index]