// 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_TRANSPOSE_BLOCKS_H
#define IGL_TRANSPOSE_BLOCKS_H
#include "igl_inline.h"

#include <Eigen/Core>

namespace igl
{
  /// Transpose blocks of a matrix
  ///
  /// @tparam T  should be a eigen matrix primitive type like int or double
  /// @param[in] A  m*k by n (dim: 1) or m by n*k (dim: 2) eigen Matrix of type T values
  /// @param[in] k  number of blocks
  /// @param[in] dim  dimension in which to transpose
  /// @param[out] B  n*k by m (dim: 1) or n by m*k (dim: 2) eigen Matrix of type T values,
  ///   NOT allowed to be the same as A
  ///
  /// #### Example:
  ///     A = [
  ///       1   2   3   4
  ///       5   6   7   8
  ///     101 102 103 104
  ///     105 106 107 108
  ///     201 202 203 204
  ///     205 206 207 208];
  ///     transpose_blocks(A,1,3,B);
  ///     B -> [
  ///       1   5
  ///       2   6
  ///       3   7
  ///       4   8
  ///     101 105
  ///     102 106
  ///     103 107
  ///     104 108
  ///     201 205
  ///     202 206
  ///     203 207
  ///     204 208];
  ///   
  template <typename T>
  IGL_INLINE void transpose_blocks(
    const Eigen::Matrix<T,Eigen::Dynamic,Eigen::Dynamic> & A,
    const size_t k,
    const size_t dim,
    Eigen::Matrix<T,Eigen::Dynamic,Eigen::Dynamic> & B);
}

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

#endif