ayulemle {degreenet}

Yule Distribution Modeling of Discrete Data

Description

Functions to Estimate the Yule Discrete Probability Distribution via maximum likelihood.

Usage

ayulemle(x, cutoff = 1, cutabove = 1000, guess = 3.5, conc = FALSE,
     method = "BFGS", hellinger = FALSE, hessian = TRUE, weights = rep(1, length(x)))

Arguments

x

A vector of counts (one per observation).

cutoff

Calculate estimates conditional on exceeding this value.

cutabove

Calculate estimates conditional on not exceeding this value.

guess

Initial estimate at the MLE.

conc

Calculate the concentration index of the distribution?

method

Method of optimization. See "optim" for details.

hellinger

Minimize Hellinger distance of the parametric model from the data instead of maximizing the likelihood.

hessian

Calculate the hessian of the information matrix (for use with calculating the standard errors.

weights

sample weights on the observed counts.

Value

theta

vector of MLE of the parameters.

asycov

asymptotic covariance matrix.

asycor

asymptotic correlation matrix.

se

vector of standard errors for the MLE.

conc

The value of the concentration index (if calculated).

Note

See the papers on https://handcock.github.io/?q=Holland for details

References

Jones, J. H. and Handcock, M. S. "An assessment of preferential attachment as a mechanism for human sexual network formation," Proceedings of the Royal Society, B, 2003, 270, 1123-1128.

See Also

ayulemle, awarmle, simyule

Examples

# Simulate a Yule distribution over 100
# observations with PDf exponent of 3.5

set.seed(1)
s4 <- simyule(n=100, rho=3.5)
table(s4)

#
# Calculate the MLE and an asymptotic confidence
# interval for the parameters
#

s4est <- ayulemle(s4)
s4est

#
# Compute the AICC and BIC for the model
#

llyuleall(v=s4est$theta,x=s4)