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mpath (version 0.4-2.26)

ncl: fit a nonconvex loss based robust linear model

Description

Fit a linear model via penalized nonconvex loss function.

Usage

# S3 method for formula
ncl(formula, data, weights, offset=NULL, contrasts=NULL, 
x.keep=FALSE, y.keep=TRUE, ...)
# S3 method for matrix
ncl(x, y, weights, offset=NULL, ...)
# S3 method for default
ncl(x,  ...)

Value

An object with S3 class "ncl" for the various types of models.

call

the call that produced this object

fitted.values

predicted values

h

pseudo response values in the MM algorithm

Arguments

formula

symbolic description of the model, see details.

data

argument controlling formula processing via model.frame.

weights

optional numeric vector of weights. If standardize=TRUE, weights are renormalized to weights/sum(weights). If standardize=FALSE, weights are kept as original input

x

input matrix, of dimension nobs x nvars; each row is an observation vector

y

response variable. Quantitative for rfamily="clossR" and -1/1 for classification.

offset

Not implemented yet

contrasts

the contrasts corresponding to levels from the respective models

x.keep, y.keep

For glmreg: logical values indicating whether the response vector and model matrix used in the fitting process should be returned as components of the returned value. For ncl_fit: x is a design matrix of dimension n * p, and x is a vector of observations of length n.

...

Other arguments passing to ncl_fit

Author

Zhu Wang <zwang145@uthsc.edu>

Details

The robust linear model is fit by majorization-minimization along with linear regression. Note that the objective function is $$weights*loss$$.

References

Zhu Wang (2021), MM for Penalized Estimation, TEST, tools:::Rd_expr_doi("10.1007/s11749-021-00770-2")

See Also

Examples

Run this code
#binomial
x=matrix(rnorm(100*20),100,20)
g2=sample(c(-1,1),100,replace=TRUE)
fit=ncl(x,g2,s=1,rfamily="closs")

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