bool StiffnessSolver::SolveSystem(
		SpMat &K, VX &D, VX &F, VX &R, 
		int DoF, VXi &q, VXi &r, 
		int verbose, int &info, double &rms_resid)
{
	VX	diag;		/* diagonal vector of the L D L' decomp. */

	diag.resize(DoF);

	//MX K_comp = K;
	int row = K.rows(), col = K.cols();
	MX K_comp(row, col);
	K_comp.setZero();

	for (int k = 0; k < K.outerSize(); ++k)
	{
		for (SpMat::InnerIterator it(K, k); it; ++it)
		{
			int		r = it.row();
			int		c = it.col();
			double	v = it.value();
			K_comp(r, c) = v;
		}
	}

	/*  L D L' decomposition of K[q,q] into lower triangle of K[q,q] and diag[q] */
	/*  vectors F and D are unchanged */
	/*  not solving at this moment*/
	LDLDecompPM(K_comp, DoF, diag, F, D, R, q, r, 1, 0, info);
	if (info < 0)
	{
		fprintf(stderr, "Stiffness Matrix is not positive definite: %d negative elements\n", info);
		fprintf(stderr, "found on decomp diagonal of K.\n");
		fprintf(stderr, "The stucture may have mechanism and thus not stable in general\n");
		fprintf(stderr, "Please Make sure that all six\n");
		fprintf(stderr, "rigid body translations are restrained!\n");
		
		return false;
	}
	else
	{
		/* LDL'  back-substitution for D[q] and R[r] */
		LDLDecompPM(K_comp, DoF, diag, F, D, R, q, r, 0, 1, info);
		if (verbose) { fprintf(stdout, "    LDL' RMS residual:"); }
		rms_resid = info = 1;

		do {
			/* improve solution for D[q] and R[r] */
			LDLImprovePM(K_comp, DoF, diag, F, D, R, q, r, rms_resid, info);
			if (verbose) { fprintf(stdout, "%9.2e", rms_resid); }
		} while (info);

		if (verbose) fprintf(stdout, "LDL^t Solving completed\n");
	}

	return true;
}
Mat solveQurdOpt(SpMat L, SpMat C, Mat alpha_star){
	//
	cout << "solving quadratic optimization proble .............." << endl;

	double lambda = 0.000001;

	SpMat D(L.rows(), L.cols());
	D.setIdentity();
	//cout << D << endl;

	alpha_star = matlab_colVector(alpha_star);
	MatrixXd as_dense;
	cv2eigen(alpha_star, as_dense);
	SpMat b = as_dense.sparseView();


	SpMat A, alpha;
	A = L + C + lambda * D;
	b = C * b;
	//cout << b << endl; 

	Eigen::SimplicialLLT<SpMat> solver;
	//Eigen::SimplicialLDLT<SpMat> solver;
	//Eigen::SparseQR<Eigen::SparseMatrix<double>> solver;
	//Eigen::BiCGSTAB<SpMat> solver;
	solver.compute(A);
	if (solver.info() != Eigen::Success) {
		cout << "decomposition failed" << endl;
	}
	cout << "decomposition success" << endl;

	cout << "begin to solve !" << endl;
	alpha = solver.solve(b);
	cout << "solve success" << endl;

	Mat cvAlpha;
	eigen2cv(Eigen::MatrixXd(alpha), cvAlpha);

	cvAlpha = cvAlpha.reshape(0, sz.width);
	cvAlpha = cvAlpha.t();

	showSavePicLBDM("alpha", cvAlpha, showImgLBDM, saveImgLBDM);

	cvAlpha = cvAlpha*0.5 + 0.5;

	cvAlpha = max(min(cvAlpha, 1.0), 0.0);

	return cvAlpha;
}
Mat solveQurdOpt(SpMat L, SpMat C, VectorXd alpha_star){
	//

	omp_set_num_threads(1); 
	Eigen::setNbThreads(1);


	cout << "solving quadratic optimization proble .............." << endl;
	double lambda = 0.000001;

	SpMat D(L.rows(), L.cols());
	D.setIdentity();

	SpMat b = alpha_star.sparseView();

	SpMat A, alpha;
	A = L + C + lambda * D;
	b = C * b;

	Eigen::SimplicialLDLT<SpMat> solver;
	cout << "begin to factorize A" << endl;
	solver.compute(A);
	if(solver.info() != Eigen::Success)
		cout << "decomposition failed" << endl;
	else
		cout << "decomposition success" << endl;

	cout << "begin to solve !" << endl;
	alpha = solver.solve(b);
	cout << "solve success" << endl;

	Mat alpha_mat;
	eigen2cv(MatrixXd(alpha), alpha_mat);
	alpha_mat = alpha_mat.t();
	alpha_mat = alpha_mat.reshape(0, imgSize.width).t();

	alpha_mat = alpha_mat * 0.5 + 0.5;

	alpha_mat = max(min(alpha_mat, 1), 0);

	//showSavePicLBDM("alpha", alpha_mat, showImgLBDM, saveImgLBDM);

	return alpha_mat;
}