#include "mex.h"

#include <stdio.h>

#include <math.h>

#include <string.h>

#include "altra.h"

/*

 * -------------------------------------------------------------------

 *                       Function and parameter

 * -------------------------------------------------------------------

 *

 * findLambdaMax compute

 * 

 * the lambda_{max} that achieves a zero solution for

 *

 *     min  1/2 \|x-v\|^2 +  \lambda_{\max} * \sum  w_i \|x_{G_i}\|,

 *

 * where x is of dimension n,

 *       w_i >=0, and G_i's follow the tree structure

 *

 * The file is implemented in the following in Matlab:

 *

 * lambdaMax=findLambdaMax(v, n, ind,nodes);

 */

void mexFunction (int nlhs, mxArray* plhs[], int nrhs, const mxArray* prhs[]){

    double*     v       =   mxGetPr(prhs[0]);

    int         n       =   (int) mxGetScalar(prhs[1]);

    double*     ind     =   mxGetPr(prhs[2]);

    int         nodes   =   (int) mxGetScalar(prhs[3]);

    double *lambdaMax;    

    /* set up output arguments */

    plhs[0] = mxCreateDoubleMatrix(1,1,mxREAL);

    lambdaMax = mxGetPr(plhs[0]);

    findLambdaMax(lambdaMax,v,n,ind,nodes);

}