libigl/include/igl/count.h

// This file is part of libigl, a simple c++ geometry processing library.
// 
// Copyright (C) 2013 Alec Jacobson <[email protected]>
// 
// 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_COUNT_H
#define IGL_COUNT_H
#include "igl_inline.h"
#include <Eigen/Sparse>

namespace igl
{

  /// Count the number of non-zeros in the columns or rows of a sparse matrix
  ///
  /// @param[in] X  m by n sparse matrix
  /// @param[in] dim  dimension along which to sum (1 or 2)
  /// @param[out] S  n-long _sparse_ vector (if dim == 1) or m-long sparse vector
  ///   (if dim == 2)
  ///
  /// \note If your looking for dense matrix matlab like sum for eigen matrics
  /// just use:
  ///      M.colwise().count() or M.rowwise().count()
  /// 
  template <typename XType, typename SType>
  IGL_INLINE void count(
    const Eigen::SparseMatrix<XType>& X, 
    const int dim,
    Eigen::SparseVector<SType>& S);
  /// \overload
  ///
  /// \brief Outputs a dense vector.
  template <typename XType, typename DerivedS>
  IGL_INLINE void count(
    const Eigen::SparseMatrix<XType>& X, 
    const int dim,
    Eigen::PlainObjectBase<DerivedS>& S);
}

#ifndef IGL_STATIC_LIBRARY
#  include "count.cpp"
#endif

#endif