R: Mahalanobis fixed point clusters initial configuration

mahalconf {fpc} | R Documentation

## Mahalanobis fixed point clusters initial configuration

### Description

Generates an initial configuration of `startn` points from dataset `x` for the `fixmahal` fixed point iteration.

Thought only for use within `fixmahal`.

### Usage

    mahalconf(x, no, startn, covall, plot)

### Arguments

`x` | numerical matrix. Rows are points, columns are variables.
`no` | integer between 1 and `nrow(x)`. Number of the first point of the configuration.
`startn` | integer between 1 and `nrow(x)`.
`covall` | covariance matrix for the computation of the first Mahalanobis distances.
`plot` | a string. If equal to `"start"` or `"both"`,the first two variables and the first `ncol(x)+1` points are plotted.

### Details

`mahalconf` first chooses the p (number of variables) nearest points to point no. `no` in terms of the Mahalanobis distance w.r.t. `covall`, so that there are p+1 points. In every further step, the covariance matrix of the current configuration is computed and the nearest point in terms of the new Mahalanobis distance is added. `solvecov` is used to invert singular covariance matrices.

### Value

A logical vector of length `nrow(x)`.

### Author(s)

Christian Hennig c.hennig@ucl.ac.uk http://www.homepages.ucl.ac.uk/~ucakche/

### See Also

`fixmahal`, `solvecov`

### Examples

      set.seed(4634)
      face <- rFace(600,dMoNo=2,dNoEy=0,p=2)
      mahalconf(face,no=200,startn=20,covall=cov(face),plot="start")

[Package fpc version 2.1-10 Index]