R gamlss::predict.gamlss 不是从 'namespace:gamlss' 导出的 object

Question

I am experiencing some confusing behavior from gamlss in R. The documentation lists predict.gamlss and ?predict.gamlss returns the function documentation in RStudio. However, the function does not autocomplete when typing out predict.gamlss , and trying to run it returns Error: 'predict.gamlss' is not an exported object from 'namespace:gamlss' . How does that happen? Is the function deactivated somehow? There is a separate function predictAll that does work.

The documentation does state

This function is under development

I am trying to access the function because I am experiencing some confusing results with predict and predictAll .

R version is 4.0.0. gamlss version is 5.1.6.

Answer 1

As far as I can tell, what you describe is expected and is normal S3 method dispatching. The method predict.gamlss is called when you call predict on a object of class gamlss .

Consider the following (from the documentation of ?predict.gamlss )

data(abdom)
aa <- gamlss(y ~ cs(x^.5), data = abdom)
#[1] 371.3931
predict(aa)[610]

Looking at the class of aa :

class(aa)
#[1] "gamlss" "gam"    "glm"    "lm"   

The function is not exported, but the S3 method is registered.

As to the difference between predictAll and predict.gamlss , you'll have to read the documentation (the two are documented together). My guess is that predictAll predict all listed in the what -argument of predict.gamlss .