From 3bd4567bdfbbfe5cbb29bcb76d5c1ef88dc13d1a Mon Sep 17 00:00:00 2001
From: Ryan Curtin <ryan@ratml.org>
Date: Fri, 5 Mar 2021 09:29:29 -0500
Subject: [PATCH] Add functions to access and modify parameters for training.

---
 src/mlpack/methods/lars/lars.cpp |  4 ++++
 src/mlpack/methods/lars/lars.hpp | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/src/mlpack/methods/lars/lars.cpp b/src/mlpack/methods/lars/lars.cpp
index 03612406fc..16bfa64124 100644
--- a/src/mlpack/methods/lars/lars.cpp
+++ b/src/mlpack/methods/lars/lars.cpp
@@ -178,6 +178,10 @@ double LARS::Train(const arma::mat& matX,
   isIgnored.clear();
   matUtriCholFactor.reset();
 
+  // Update values in case lambda1 or lambda2 changed.
+  lasso = (lambda1 != 0);
+  elasticNet = (lambda1 != 0 && lambda2 != 0);
+
   // This matrix may end up holding the transpose -- if necessary.
   arma::mat dataTrans;
   // dataRef is row-major.
diff --git a/src/mlpack/methods/lars/lars.hpp b/src/mlpack/methods/lars/lars.hpp
index 8989d13e55..d019fec900 100644
--- a/src/mlpack/methods/lars/lars.hpp
+++ b/src/mlpack/methods/lars/lars.hpp
@@ -249,6 +249,26 @@ class LARS
                arma::rowvec& predictions,
                const bool rowMajor = false) const;
 
+  //! Get the L1 regularization coefficient.
+  double Lambda1() const { return lambda1; }
+  //! Modify the L1 regularization coefficient.
+  double& Lambda1() { return lambda1; }
+
+  //! Get the L2 regularization coefficient.
+  double Lambda2() const { return lambda2; }
+  //! Modify the L2 regularization coefficient.
+  double& Lambda2() { return lambda2; }
+
+  //! Get whether to use the Cholesky decomposition.
+  bool UseCholesky() const { return useCholesky; }
+  //! Modify whether to use the Cholesky decomposition.
+  bool& UseCholesky() { return useCholesky; }
+
+  //! Get the tolerance for maximum correlation during training.
+  double Tolerance() const { return tolerance; }
+  //! Modify the tolerance for maximum correlation during training.
+  double& Tolerance() { return tolerance; }
+
   //! Access the set of active dimensions.
   const std::vector<size_t>& ActiveSet() const { return activeSet; }