regsubsets {leaps}R Documentation

functions for model selection

Description

Generic function for regression subset selection with methods for formula and matrix arguments.

Usage

regsubsets(x=, ...)

## S3 method for class 'formula':
regsubsets(x=, data=, weights=NULL, nbest=1, nvmax=8, force.in=NULL, force.out=NULL, intercept=TRUE, method=c("exhaustive", "backward", "forward", "seqrep"), really.big=FALSE,...)

## Default S3 method:
regsubsets(x=, y=, weights=rep(1, length(y)), nbest=1, nvmax=8,
force.in=NULL, force.out=NULL, intercept=TRUE, method=c("exhaustive",
"backward", "forward", "seqrep"), really.big=FALSE,...)

## S3 method for class 'regsubsets':
summary(object,all.best=TRUE,matrix=TRUE,matrix.logical=FALSE,df=NULL,...)

Arguments

x design matrix or model formula for full model
data Optional data frame
y response vector
weights weight vector
nbest number of subsets of each size to record
nvmax maximum size of subsets to examine
force.in index to columns of design matrix that should be in all models
force.out index to columns of design matrix that should be in no models
intercept Add an intercept?
method Use exhaustive search, forward selection, backward selection or sequential replacement to search.
really.big Must be TRUE to perform exhaustive search on more than 50 variables.
object regsubsets object
all.best Show all the best subsets or just one of each size
matrix Show a matrix of the variables in each model or just summary statistics
matrix.logical With matrix=TRUE, the matrix is logical TRUE/FALSE or string "*"/code{" "}
df Specify a number of degrees of freedom for the summary statistics. The default is n-1
... Other arguments for future methods

Value

An object of class "regsubsets" containing no user-serviceable parts. It is designed to be processed by summary.regsubsets.

Note

This function improves on leaps in several ways. The design matrix need not be of full rank. The ability to restrict nvmax speeds up exhaustive searches considerably. There is no hard-coded limit to the number of variables.

See Also

leaps

Examples

data(swiss)
a<-regsubsets(as.matrix(swiss[,-1]),swiss[,1])
summary(a)
b<-regsubsets(Fertility~.,data=swiss)
summary(a)

[Package leaps version 2.7 Index]