dust3d/third_party/libigl/include/igl/slice.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_SLICE_H
#define IGL_SLICE_H
#include "igl_inline.h"
#include <Eigen/Sparse>
namespace igl
{
// Act like the matlab X(row_indices,col_indices) operator, where
// row_indices, col_indices are non-negative integer indices.
//
// Inputs:
// X m by n matrix
// R list of row indices
// C list of column indices
// Output:
// Y #R by #C matrix
//
// See also: slice_mask
template <
typename TX,
typename TY>
IGL_INLINE void slice(
const Eigen::SparseMatrix<TX>& X,
const Eigen::Matrix<int,Eigen::Dynamic,1> & R,
const Eigen::Matrix<int,Eigen::Dynamic,1> & C,
Eigen::SparseMatrix<TY>& Y);
// Wrapper to only slice in one direction
//
// Inputs:
// dim dimension to slice in 1 or 2, dim=1 --> X(R,:), dim=2 --> X(:,R)
//
// Note: For now this is just a cheap wrapper.
template <
typename MatX,
typename DerivedR,
typename MatY>
IGL_INLINE void slice(
const MatX& X,
const Eigen::DenseBase<DerivedR> & R,
const int dim,
MatY& Y);
template <
typename DerivedX,
typename DerivedR,
typename DerivedC,
typename DerivedY>
IGL_INLINE void slice(
const Eigen::DenseBase<DerivedX> & X,
const Eigen::DenseBase<DerivedR> & R,
const Eigen::DenseBase<DerivedC> & C,
Eigen::PlainObjectBase<DerivedY> & Y);
template <typename DerivedX, typename DerivedY>
IGL_INLINE void slice(
const Eigen::DenseBase<DerivedX> & X,
const Eigen::Matrix<int,Eigen::Dynamic,1> & R,
Eigen::PlainObjectBase<DerivedY> & Y);
// VectorXi Y = slice(X,R);
//
// This templating is bad because the return type might not have the same
// size as `DerivedX`. This will probably only work if DerivedX has Dynamic
// as it's non-trivial sizes or if the number of rows in R happens to equal
// the number of rows in `DerivedX`.
template <typename DerivedX>
IGL_INLINE DerivedX slice(
const Eigen::DenseBase<DerivedX> & X,
const Eigen::Matrix<int,Eigen::Dynamic,1> & R);
template <typename DerivedX>
IGL_INLINE DerivedX slice(
const Eigen::DenseBase<DerivedX>& X,
const Eigen::Matrix<int,Eigen::Dynamic,1> & R,
const int dim);
}
#ifndef IGL_STATIC_LIBRARY
# include "slice.cpp"
#endif
#endif