dust3d/third_party/libigl/include/igl/diag.h

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// 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/.
#ifndef IGL_DIAG_H
#define IGL_DIAG_H
#include "igl_inline.h"
#define EIGEN_YES_I_KNOW_SPARSE_MODULE_IS_NOT_STABLE_YET
#include <Eigen/Sparse>
namespace igl
{
// http://forum.kde.org/viewtopic.php?f=74&t=117476&p=292388#p292388
//
// This is superceded by
// VectorXd V = X.diagonal() and
// SparseVector<double> V = X.diagonal().sparseView()
// SparseMatrix<double> X = V.asDiagonal().sparseView()
//
//
// Either extracts the main diagonal of a matrix as a vector OR converts a
// vector into a matrix with vector along the main diagonal. Like matlab's
// diag function
// Templates:
// T should be a eigen sparse matrix primitive type like int or double
// Inputs:
// X an m by n sparse matrix
// Outputs:
// V a min(m,n) sparse vector
template <typename T>
IGL_INLINE void diag(
const Eigen::SparseMatrix<T>& X,
Eigen::SparseVector<T>& V);
template <typename T,typename DerivedV>
IGL_INLINE void diag(
const Eigen::SparseMatrix<T>& X,
Eigen::MatrixBase<DerivedV>& V);
// Templates:
// T should be a eigen sparse matrix primitive type like int or double
// Inputs:
// V a m sparse vector
// Outputs:
// X a m by m sparse matrix
template <typename T>
IGL_INLINE void diag(
const Eigen::SparseVector<T>& V,
Eigen::SparseMatrix<T>& X);
template <typename T, typename DerivedV>
IGL_INLINE void diag(
const Eigen::MatrixBase<DerivedV>& V,
Eigen::SparseMatrix<T>& X);
}
#ifndef IGL_STATIC_LIBRARY
# include "diag.cpp"
#endif
#endif