You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: sparseInverseCovariance.m
    path of file: ./repos/CS_MoCo_LAB/reconstruction/matlab/CS_LAB_matlab/utils/utils_SLEP/SLEP/functions/invCov
    
    the code of the file until where you have to start completion: function Theta=sparseInverseCovariance(S, lambda, opts)
%
% Function sparseInverseCovariance
%   sparse inverse covariance estimation
%
%% Problem
%
%   max log( det( Theta ) ) - < S, Theta> - lambda * ||Theta||_1
%
%% Input parameters:
%
% S-          Empirical covariance matrix
% lambda-     regularization parameter
% opts-       optional inputs
%
%% Output parameter:
% Theta-      sparse inverse covariance
%
%% Copyright (C) 2009-2010 Jun Liu, and Jieping Ye
%
% You are suggested to first read the Manual.
%
% For any problem, please contact with Jun Liu via j.liu@asu.edu
%
% Composed on September 18, 2008.
%
%% Related papers
%

    
function Theta=sparseInverseCovariance(S, lambda, opts)
%
% Function sparseInverseCovariance
%   sparse inverse covariance estimation
%
%% Problem
%
%   max log( det( Theta ) ) - < S, Theta> - lambda * ||Theta||_1
%
%% Input parameters:
%
% S-          Empirical covariance matrix
% lambda-     regularization parameter
% opts-       optional inputs
%
%% Output parameter:
% Theta-      sparse inverse covariance
%
%% Copyright (C) 2009-2010 Jun Liu, and Jieping Ye
%
% You are suggested to first read the Manual.
%
% For any problem, please contact with Jun Liu via j.liu@asu.edu
%
% Composed on September 18, 2008.
%
%% Related papers
%
% The implementation is based on the following paper:
%
% [1]  Jerome Friedman, Trevor Hastie, and Robert Tibshirani,
%      Sparse inverse covariance estimation with the graphical lasso, 2007
%
% This function has been used in the following paper:
%
% [2] Shuai Huang, Jing Li, Liang Sun, Jun Liu, Teresa Wu,
%     Kewei Chen, Adam Fleisher, Eric Reiman, and Jieping Ye,
%     Learning Brain Connectivity of Alzheimer's Disease 
%     from Neuroimaging Data, NIPS, 2009
%
%% Related functions
%
%  invCov.c
%

% Verify the number of input parameters
if (nargin <2)
    error('\n Inputs: S and lambda should be specified!\n');
elseif (nargin==3)
    opts=[];
end