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accSDA (version 1.0.0)

APG_EN2: Accelerated Proximal Gradient on l1 regularized quadratic program

Description

Applies accelerated proximal gradient algorithm to the l1-regularized quadratic program $$f(\mathbf{x}) + g(\mathbf{x}) = \frac{1}{2}\mathbf{x}^TA\mathbf{x} - d^T\mathbf{x} + \lambda |\mathbf{x}|_1$$

Usage

APG_EN2(A, d, x0, lam, alpha, maxits, tol)

Arguments

A

p by p positive definite coefficient matrix $$A = (\gamma Om + X^T X/n)$$.

d

nx1 dimensional column vector.

lam

Regularization parameter for l1 penalty, must be greater than zero.

alpha

Step length.

maxits

Number of iterations to run

tol

Stopping tolerance for proximal gradient algorithm.

Value

APG_EN2 returns an object of class "APG_EN2" including a list with the following named components

call

The matched call.

x

Found solution.

k

Number of iterations used.

Details

This function is used by other functions and should only be called explicitly for debugging purposes.

See Also

Used by: SDAAP and the SDAAPcv cross-validation version.