rigff {VGAM} | R Documentation

## Reciprocal Inverse Gaussian distribution

### Description

Estimation of the parameters of a reciprocal inverse Gaussian distribution.

### Usage

    rigff(lmu = "identitylink", llambda = "loglink", imu = NULL, ilambda = 1)

### Arguments

`lmu, llambda` | Link functions for `mu` and `lambda`. See `Links` for more choices.
`imu, ilambda` | Initial values for `mu` and `lambda`. A `NULL` means a value is computed internally.

### Details

See Jorgensen (1997) for details.

### Value

An object of class `"vglmff"` (see `vglmff-class`). The object is used by modelling functions such as `vglm`, and `vgam`.

### Note

This distribution is potentially useful for dispersion modelling.

### Author(s)

T. W. Yee

### References

Jorgensen, B. (1997) The Theory of Dispersion Models. London: Chapman & Hall

### See Also

`simplex`.

### Examples

    rdata <- data.frame(y = rchisq(n = 100, df = 14))  # Not 'proper' data!!
    fit <- vglm(y ~ 1, rigff, data = rdata, trace = TRUE)
    fit <- vglm(y ~ 1, rigff, data = rdata, trace = TRUE, eps = 1e-9, crit = "coef")
    summary(fit)

[Package VGAM version 1.1-1 Index]