R: Extract Model Coefficients

coefvlm {VGAM} | R Documentation

## Extract Model Coefficients

### Description

Extracts the estimated coefficients from VLM objects such as VGLMs.

### Usage

    coefvlm(object, matrix.out = FALSE, label = TRUE, colon = FALSE)

### Arguments

`object` | An object for which the extraction of coefficients is meaningful. This will usually be a `vglm` object.
`matrix.out` | Logical. If `TRUE` then a matrix is returned. The explanatory variables are the rows. The linear/additive predictors are the columns. The constraint matrices are used to compute this matrix.
`label` | Logical. If `FALSE` then the `names` of the vector of coefficients are set to `NULL`.
`colon` | Logical. Explanatory variables which appear in more than one linear/additive predictor are labelled with a colon, e.g., `age:1`, `age:2`. However, if it only appears in one linear/additive predictor then the `:1` is omitted by default. Then setting `colon = TRUE` will add the `:1`.

### Details

This function works in a similar way to applying `coef()` to a `lm` or `glm` object. However, for VGLMs, there are more options available.

### Value

A vector usually. A matrix if `matrix.out = TRUE`.

### Author(s)

Thomas W. Yee

### References

Yee, T. W. and Hastie, T. J. (2003) Reduced-rank vector generalized linear models. Statistical Modelling, 3, 15–41.

### See Also

`vglm`, `coefvgam`, `coef`.

### Examples

    zdata <- data.frame(x2 = runif(nn <- 200))
    zdata <- transform(zdata, pstr0  = logit(-0.5 + 1*x2, inverse = TRUE),
                              lambda = loge(  0.5 + 2*x2, inverse = TRUE))
    zdata <- transform(zdata, y2 = rzipois(nn, lambda, pstr0 = pstr0))

    fit2 <- vglm(y2 ~ x2, zipoisson(zero = 1), data = zdata, trace = TRUE)
    coef(fit2, matrix = TRUE)  # Always a good idea
    coef(fit2)
    coef(fit2, colon = TRUE)

[Package VGAM version 1.0-3 Index]