33 lines
981 B
C++
33 lines
981 B
C++
|
// This file is part of libigl, a simple c++ geometry processing library.
|
||
|
|
//
|
||
|
|
// Copyright (C) 2013 Alec Jacobson <alecjacobson@gmail.com>
|
||
|
|
//
|
||
|
|
// This Source Code Form is subject to the terms of the Mozilla Public License
|
||
|
|
// v. 2.0. If a copy of the MPL was not distributed with this file, You can
|
||
|
|
// obtain one at http://mozilla.org/MPL/2.0/.
|
||
|
|
#include "orth.h"
|
||
|
|
|
||
|
|
// Broken Implementation
|
||
|
|
IGL_INLINE void igl::orth(const Eigen::MatrixXd &A, Eigen::MatrixXd &Q)
|
||
|
|
{
|
||
|
|
|
||
|
|
//perform svd on A = U*S*V' (V is not computed and only the thin U is computed)
|
||
|
|
Eigen::JacobiSVD<Eigen::MatrixXd> svd(A, Eigen::ComputeThinU );
|
||
|
|
Eigen::MatrixXd U = svd.matrixU();
|
||
|
|
const Eigen::VectorXd S = svd.singularValues();
|
||
|
|
|
||
|
|
//get rank of A
|
||
|
|
int m = A.rows();
|
||
|
|
int n = A.cols();
|
||
|
|
double tol = std::max(m,n) * S.maxCoeff() * 2.2204e-16;
|
||
|
|
int r = 0;
|
||
|
|
for (int i = 0; i < S.rows(); ++r,++i)
|
||
|
|
{
|
||
|
|
if (S[i] < tol)
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
//keep r first columns of U
|
||
|
|
Q = U.block(0,0,U.rows(),r);
|
||
|
|
}
|