VGAM (version 1.1-2)

model.framevlm: Construct the Model Frame of a VLM Object

Description

This function returns a data.frame with the variables. It is applied to an object which inherits from class "vlm" (e.g., a fitted model of class "vglm").

Usage

model.framevlm(object, setupsmart = TRUE, wrapupsmart = TRUE, …)

Arguments

object

a model object from the VGAM R package that inherits from a vector linear model (VLM), e.g., a model of class "vglm".

…

further arguments such as data, na.action, subset. See model.frame for more information on these.

setupsmart, wrapupsmart

Logical. Arguments to determine whether to use smart prediction.

Value

A data.frame containing the variables used in the object plus those specified in ….

Details

Since object is an object which inherits from class "vlm" (e.g., a fitted model of class "vglm"), the method will either returned the saved model frame used when fitting the model (if any, selected by argument model = TRUE) or pass the call used when fitting on to the default method.

This code implements smart prediction (see smartpred).

References

Chambers, J. M. (1992) Data for models. Chapter 3 of Statistical Models in S eds J. M. Chambers and T. J. Hastie, Wadsworth & Brooks/Cole.

See Also

model.frame, model.matrixvlm, predictvglm, smartpred.

Examples

# NOT RUN {
# Illustrates smart prediction
pneumo <- transform(pneumo, let = log(exposure.time))
fit <- vglm(cbind(normal,mild, severe) ~ poly(c(scale(let)), 2),
            multinomial, data = pneumo, trace = TRUE, x = FALSE)
class(fit)

check1 <- head(model.frame(fit))
check1
check2 <- model.frame(fit, data = head(pneumo))
check2
all.equal(unlist(check1), unlist(check2))  # Should be TRUE

q0 <- head(predict(fit))
q1 <- head(predict(fit, newdata = pneumo))
q2 <- predict(fit, newdata = head(pneumo))
all.equal(q0, q1)  # Should be TRUE
all.equal(q1, q2)  # Should be TRUE
# }