R: EM Control Generator and Controller

EM Control {EMCluster} | R Documentation

## EM Control Generator and Controller

### Description

The `.EMControl` generates an EM control (`.EMC`) controlling the options and conditions of EM algorithms, i.e. this function generate a default template. One can either modify `.EMC` or employ this function to control EM algorithms. By default, `.EMC`, `.EMC.Rnd`, and `.EC.Rndp` are three native controllers as the EMCluster is loaded.

### Usage

    .EMControl(alpha = 0.99, short.iter = 200, short.eps = 1e-2,
        fixed.iter = 1, n.candidate = 3,
        em.iter = 1000, em.eps = 1e-6, exhaust.iter = 5)
    .EMC
    .EMC.Rnd
    .EMC.Rndp

### Arguments

`alpha` | only used in `emgroup` for "SVD" initialization.
`short.iter` | number of short-EM steps, default = 200.
`short.eps` | tolerance of short-EM steps, default = 1e-2.
`fixed.iter` | fixed iterations of EM for "RndEM" initialization, default = 1.
`n.candidate` | reserved for other initialization methods (unimplemented).
`em.iter` | maximum number of long-EM steps, default = 1000.
`em.eps` | tolerance of long-EM steps, default = 1e-6.
`exhaust.iter` | number of iterations for "exhaustEM" initialization, default = 5.

### Details

`exhaust.iter` and `fixed.iter` are used to control the iterations of initialization procedures.

`short.iter` and `short.eps` are used to control the short-EM iterations.

`em.iter` and `em.eps` are used to control the long-EM iterations.

Moeover, `short.eps` and `em.eps` are for checking convergence of the iterations.

### Value

This function returns a list as `.EMC` by default.

The `.EMC.Rnd` is equal to `.EMControl(short.eps = Inf)` and usually used by the `rand.EM` method.

The `.EMC.Rndp` is equal to `.EMControl(fixed.iter = 5)` where each random initials run 5 EM iterations in the `rand.EM` method.

### Author(s)

Wei-Chen Chen wccsnow@gmail.com and Ranjan Maitra.

### References

https://www.stat.iastate.edu/people/ranjan-maitra

### See Also

`init.EM`, `emcluster`.

### Examples

    library(EMCluster, quietly = TRUE)

    .EMC <- .EMControl()
    .EMC.Rnd <- .EMControl(short.eps = Inf)
    .EMC.Rndp <- .EMControl(fixed.iter = 5)

[Package EMCluster version 0.2-13 Index]