VEM {Icens} | R Documentation |

## Compute the NPMLE of p via the Vertex Exchange Method.

### Description

The Vertex Exchange Method is used to obtain the NPMLE of `p`

.

### Usage

VEM(A, pvec, maxiter=500, tol=1e-07, tolbis=1e-07), keepiter=FALSE)

### Arguments

`A` |
The m by n incidence matrix or the n by 2 matrix of intervals. |

`pvec` |
The initial estimate for the probability vector. |

`maxiter` |
The maximum number of iterations allowed. |

`tol` |
The tolerance used to determine convergence. |

`tolbis` |
The tolerance used in the bisection stage of the
algorithm. |

`keepiter` |
Should iteration information be retained and returned. |

### Details

Lots.

### Value

An object of class `icsurv`

with the following components.

`pf ` |
The NPMLE of the probability vector. |

`numiter ` |
The number of iterations used. |

`lval` |
The value of the logarithm of the likelihood at the
NPMLE. |

`converge` |
Boolean stating whether the iteration converged. |

`intmap` |
If present it contains the real representations for the
maximimal cliques. These are the intervals (on the real line) where
the mass in `pf` is placed. |

### Author(s)

Robert Gentleman and Alain Vandal

### References

*A Vertex-exchange-method in $D$-optimal Design Theory
*, D. Bohning, Metrika, 1986.

### See Also

`EM`

, `ISDM`

, `EMICM`

,
`PGM`

### Examples

data(cosmesis)
csub1 <- subset(cosmesis, subset=Trt==0, select=c(L,R))
VEM(csub1)
data(pruitt)
VEM(pruitt)

[Package

*Icens* version 0.5

Index]