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Computational Framework for L$_{2}$E Structured Regression Problems

The L2E package (version 2.0) implements the computational framework for L$_2$E regression in Liu, Chi, and Lange (2022+), which was built on the previous work in Chi and Chi (2022). Both works employ the block coordinate descent strategy to solve a nonconvex optimization problem but utilize different methods for the inner block descent updates. We refer to the method in Liu, Chi, and Lange (2022+) as "MM" and the one in Chi and Chi (2022) as "PG" in our package. This package provides code to replicate some examples illustrating the usage of the frameworks in both manuscripts.

Installation

To install the latest stable version from CRAN:

install.packages('L2E')

To install the latest development version from GitHub:

# install.packages("devtools")
devtools::install_github('jocelynchi/L2E-package-demo')

Getting Started

We've included an introductory demo on how to use the L2E framework with examples from the accompanying journal manuscripts.

Citing the package

Please reference the following manuscripts when citing this package. Thank you!


@article{L2E-Chi,
  title={A User-Friendly Computational Framework for Robust Structured Regression with the L$_2$ Criterion},
  author={Chi, Jocelyn T. and Chi, Eric C.},
  journal={Journal of Computational and Graphical Statistics},
  pages={1--12},
  year={2022},
  publisher={Taylor \& Francis}
}
@article{L2E-Liu,
  title={A Sharper Computational Tool for L$_2$E  Regression},
  author={Liu, Xiaoqian and Chi, Eric C. and Lange, Kenneth},
  journal={arXiv preprint arXiv:2203.02993},
  year={2022}
}

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Version

Install

install.packages('L2E')

Monthly Downloads

218

Version

2.0

License

GPL (>= 2)

Maintainer

Jocelyn Chi

Last Published

September 8th, 2022

Functions in L2E (2.0)

CV_L2E_TF_lasso

Cross validation for L2E trend filtering regression with Lasso penalization
L2E_isotonic

L2E isotonic regression
l2e_regression

L2E multivariate regression - PG
L2E_multivariate

L2E multivariate regression
l2e_regression_convex_MM

L2E convex regression - MM
bank

Bank data
l2e_regression_sparse_ncv

L2E sparse regression with existing penalization methods
l2e_regression_isotonic

L2E isotonic regression - PG
myGetDkn

Compute kth order differencing matrix
update_beta_MM_isotonic

Beta update in L2E isotonic regression - MM
update_beta_MM_ls

Beta update in L2E multivariate regression - MM
l2e_regression_TF_lasso

L2E trend filtering regression with Lasso penalization
l2e_regression_isotonic_MM

L2E isotonic regression - MM
l2e_regression_convex

L2E convex regression - PG
L2E_TF_lasso

Solution path of the L2E trend filtering regression with Lasso
l2e_regression_MM

L2E multivariate regression - MM
objective

Objective function of the L2E regression - eta
objective_tau

Objective function of the L2E regression - tau
CV_L2E_sparse_dist

Cross validation for L2E sparse regression with distance penalization
l2e_regression_TF_dist

L2E trend filtering regression with distance penalization
update_beta_MM_sparse

Beta update in L2E sparse regression - MM
update_beta_convex

Beta update in L2E convex regression - PG
update_beta_MM_TF

Beta update in L2E trend filtering regression - MM
update_eta_bktk

Eta update using Newton's method with backtracking
L2E_sparse_dist

Solution path of L2E sparse regression with distance penalization
L2E_sparse_ncv

Solution path of L2E sparse regression with existing penalization methods
update_beta_isotonic

Beta update in L2E isotonic regression - PG
update_beta_MM_convex

Beta update in L2E convex regression - MM
update_tau_R

Tau update function
l2e_regression_sparse_dist

L2E sparse regression with distance penalization
update_beta_qr

Beta update in L2E multivariate regression - PG
update_beta_TF_lasso

Beta update in L2E trend filtering regression using Lasso
update_beta_sparse_ncv

Beta update in L2E sparse regression - NCV
L2E_convex

L2E convex regression
CV_L2E_sparse_ncv

Cross validation for L2E sparse regression with existing penalization methods
L2E

L2E
L2E_TF_dist

Solution path of the L2E trend filtering regression with distance penalization
CV_L2E_TF_dist

Cross validation for L2E trend filtering regression with distance penalization