model.matrixvlm {VGAM} | R Documentation |
Creates a design matrix. Two types can be
returned: a large one (class "vlm"
or one that inherits
from this such as "vglm"
) or a small one
(such as returned if it were of class "lm"
).
model.matrixvlm(object, type=c("vlm","lm"), ...)
object |
an object of a class that inherits from the vector linear model (VLM). |
type |
Type of design matrix returned. The first is the default. |
... |
further arguments passed to or from other methods.
These include data (which
is a data frame created with model.framevlm ),
contrasts.arg , and xlev .
See model.matrix for more information.
|
This function creates a design matrix from object
.
This can be a small LM object or a big VLM object (default).
The latter is constructed from the former and the constraint
matrices.
This code implements smart prediction
(see smartpred
).
The design matrix for a regression model with the specified formula and data.
Yee, T. W. and Hastie, T. J. (2003) Reduced-rank vector generalized linear models. Statistical Modelling, 3, 15–41.
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.
model.matrix
,
model.framevlm
,
predict.vglm
,
smartpred
.
# Illustrates smart prediction data(pneumo) pneumo = transform(pneumo, let=log(exposure.time)) fit = vglm(cbind(normal,mild, severe) ~ poly(c(scale(let)), 2), fam=multinomial, data=pneumo, trace=TRUE, x=FALSE) class(fit) fit@x model.matrix(fit) Check1 = model.matrix(fit, type="lm")[1:3,] Check1 Check2 = model.matrix(fit, data=pneumo[1:3,], type="lm") Check2 all.equal(c(Check1), c(Check2)) q0 = predict(fit)[1:3,] q1 = predict(fit, newdata=pneumo)[1:3,] q2 = predict(fit, newdata=pneumo[1:3,]) all.equal(q0, q1) # Should be TRUE all.equal(q1, q2) # Should be TRUE