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mable (version 4.1.1)

madem.density: Minimum Approximate Distance Estimate of univariate Density Function with given model degree(s)

Description

Minimum Approximate Distance Estimate of univariate Density Function with given model degree(s)

Usage

madem.density(
  x,
  m,
  p = rep(1, prod(m + 1))/prod(m + 1),
  interval = NULL,
  method = c("qp", "em"),
  maxit = 10000,
  eps = 1e-07
)

Value

An invisible mable object with components

  • m the given model degree(s)

  • p the estimated vector of mixture proportions with the given optimal degree(s) m

  • interval support/truncation interval [a, b]

  • D the minimum distance at degree m

Arguments

x

an n x d matrix or data.frame of multivariate sample of size n

m

a positive integer or a vector of d positive integers specify the given model degrees for the joint density.

p

initial guess of p

interval

a vector of two endpoints or a 2 x d matrix, each column containing the endpoints of support/truncation interval for each marginal density. If missing, the i-th column is assigned as c(min(x[,i]), max(x[,i])).

method

method for finding minimum distance estimate. "em": EM like method;

maxit

the maximum iterations

eps

the criterion for convergence

Details

A \(d\)-variate cdf \(F\) on a hyperrectangle \([a, b] =[a_1, b_1] \times \cdots \times [a_d, b_d]\) can be approximated by a mixture of \(d\)-variate beta cdfs on \([a, b]\), \(\beta_{mj}(x) = \prod_{i=1}^dB_{m_i,j_i}[(x_i-a_i)/(b_i-a_i)]\), with proportion \(p(j_1, \ldots, j_d)\), \(0 \le j_i \le m_i, i = 1, \ldots, d\). With a given model degree m, the parameters p, the mixing proportions of the beta distribution, are calculated as the minimizer of the approximate \(L_2\) distance between the empirical distribution and the Bernstein polynomial model. The quadratic programming with linear constraints is used to solve the problem.