R: Rank

Rank {VGAM} | R Documentation

## Rank

### Description

Returns the rank of reduced-rank regression-type models in the VGAM package.

### Usage

        Rank(object, ...)
        Rank.rrvglm(object, ...)
        Rank.qrrvglm(object, ...)
        Rank.rrvgam(object, ...)

### Arguments

`object` | Some VGAM object, for example, having class `rrvglm-class`. The class `vglm-class` is not included since this is not based on reduced-rank regression.
`...` | Other possible arguments fed into the function later (used for added flexibility for the future).

### Details

Regression models based on reduced-rank regression have a quantity called the rank, which is 1 or 2 or 3 etc. The smaller the value the more dimension reduction, so that there are fewer parameters. This function was not called `rank()` to avoid conflict with `rank`.

### Value

Returns an integer value, provided the rank of the model makes sense.

### Note

This function has not been defined for VGLMs yet. It might refer to the rank of the VL model matrix, but for now this function should not be applied to `vglm` fits.

### Author(s)

T. W. Yee.

### See Also

RR-VGLMs are described in `rrvglm-class`; QRR-VGLMs are described in `qrrvglm-class`.

### Examples

    pneumo <- transform(pneumo, let = log(exposure.time),
                                x3  = runif(nrow(pneumo)))
    (fit1 <- rrvglm(cbind(normal, mild, severe) ~ let + x3,
                    acat, data = pneumo))
    coef(fit1, matrix = TRUE)
    constraints(fit1)
    Rank(fit1)

[Package VGAM version 1.1-3 Index]