include/ceres/internal/eigen.h

// Ceres Solver - A fast non-linear least squares minimizer
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// http://ceres-solver.org/
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// Author: sameeragarwal@google.com (Sameer Agarwal)

#ifndef CERES_INTERNAL_EIGEN_H_
#define CERES_INTERNAL_EIGEN_H_

#include "Eigen/Core"

namespace ceres {

using Vector = Eigen::Matrix<double, Eigen::Dynamic, 1>;
using Matrix =
    Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>;
using VectorRef = Eigen::Map<Vector>;
using MatrixRef = Eigen::Map<Matrix>;
using ConstVectorRef = Eigen::Map<const Vector>;
using ConstMatrixRef = Eigen::Map<const Matrix>;

// Column major matrices for DenseSparseMatrix/DenseQRSolver
using ColMajorMatrix =
    Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic, Eigen::ColMajor>;

using ColMajorMatrixRef =
    Eigen::Map<ColMajorMatrix, 0, Eigen::Stride<Eigen::Dynamic, 1>>;

using ConstColMajorMatrixRef =
    Eigen::Map<const ColMajorMatrix, 0, Eigen::Stride<Eigen::Dynamic, 1>>;

// C++ does not support templated typdefs, thus the need for this
// struct so that we can support statically sized Matrix and Maps.
template <int num_rows = Eigen::Dynamic, int num_cols = Eigen::Dynamic>
struct EigenTypes {
  using Matrix =
      Eigen::Matrix<double,
                    num_rows,
                    num_cols,
                    num_cols == 1 ? Eigen::ColMajor : Eigen::RowMajor>;

  using MatrixRef = Eigen::Map<Matrix>;
  using ConstMatrixRef = Eigen::Map<const Matrix>;
  using Vector = Eigen::Matrix<double, num_rows, 1>;
  using VectorRef = Eigen::Map<Eigen::Matrix<double, num_rows, 1>>;
  using ConstVectorRef = Eigen::Map<const Eigen::Matrix<double, num_rows, 1>>;
};

}  // namespace ceres

#endif  // CERES_INTERNAL_EIGEN_H_