fmx_constraint function

Parameter Constraint(s) of Mixture Distribution

Determine the parameter constraint(s) of a finite mixture distribution fmx , either by the value of parameters of such mixture distribution, or by a user-specified string.

fmx_constraint(
  dist,
  distname = dist@distname,
  K = dim(dist@pars)[1L],
  pars = dist@pars
)

Arguments

• dist: (optional) fmx object
• distname: character scalar, name of distribution (see fmx ), default value determined by dist
• K: integer scalar, number of components, default value determined by dist
• pars: double matrix , distribution parameters of a finite mixture distribution (see fmx ), default value determined by dist

Returns

Function fmx_constraint() returns the indices of internal parameters (only applicable to Tukey $g$-&-$h$ mixture distribution, yet) to be constrained, based on the input fmx object dist.

Examples

(d0 = fmx('GH', A = c(1,4), g = c(.2,.1), h = c(.05,.1), w = c(1,1)))
(c0 = fmx_constraint(d0))
user_constraint(character(), distname = 'GH', K = 2L) # equivalent

(d1 = fmx('GH', A = c(1,4), g = c(.2,0), h = c(0,.1), w = c(1,1)))
(c1 = fmx_constraint(d1))
user_constraint(c('g2', 'h1'), distname = 'GH', K = 2L) # equivalent

(d2 = fmx('GH', A = c(1,4), g = c(.2,0), h = c(.15,.1), w = c(1,1)))
(c2 = fmx_constraint(d2))
user_constraint('g2', distname = 'GH', K = 2L) # equivalent