text: // This file is part of Eigen, a lightweight C++ template library
  // for linear algebra.
  //
  // Copyright (C) 2009 Benoit Jacob <jacob.benoit.1@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/.
  
  // This is a pure C header, no C++ here.
  // The functions declared here will be implemented in C++ but
  // we don't have to know, because thanks to the extern "C" syntax,
  // they will be compiled to C object code.
  
  #ifdef __cplusplus
  extern "C"
  {
  #endif
  
    // just dummy empty structs to give different pointer types,
    // instead of using void* which would be type unsafe
    struct C_MatrixXd {};
    struct C_Map_MatrixXd {};
  
    // the C_MatrixXd class, wraps some of the functionality
    // of Eigen::MatrixXd.
    struct C_MatrixXd* MatrixXd_new(int rows, int cols);
    void    MatrixXd_delete     (struct C_MatrixXd *m);
    double* MatrixXd_data       (struct C_MatrixXd *m);
    void    MatrixXd_set_zero   (struct C_MatrixXd *m);
    void    MatrixXd_resize     (struct C_MatrixXd *m, int rows, int cols);
    void    MatrixXd_copy       (struct C_MatrixXd *dst,
                                 const struct C_MatrixXd *src);
    void    MatrixXd_copy_map   (struct C_MatrixXd *dst,
                                 const struct C_Map_MatrixXd *src);  
    void    MatrixXd_set_coeff  (struct C_MatrixXd *m,
                                 int i, int j, double coeff);
    double  MatrixXd_get_coeff  (const struct C_MatrixXd *m,
                                 int i, int j);
    void    MatrixXd_print      (const struct C_MatrixXd *m);
    void    MatrixXd_add        (const struct C_MatrixXd *m1,
                                 const struct C_MatrixXd *m2,
                                 struct C_MatrixXd *result);  
    void    MatrixXd_multiply   (const struct C_MatrixXd *m1,
                                 const struct C_MatrixXd *m2,
                                 struct C_MatrixXd *result);
    
    // the C_Map_MatrixXd class, wraps some of the functionality
    // of Eigen::Map<MatrixXd>
    struct C_Map_MatrixXd* Map_MatrixXd_new(double *array, int rows, int cols);
    void   Map_MatrixXd_delete     (struct C_Map_MatrixXd *m);
    void   Map_MatrixXd_set_zero   (struct C_Map_MatrixXd *m);
    void   Map_MatrixXd_copy       (struct C_Map_MatrixXd *dst,
                                    const struct C_Map_MatrixXd *src);
    void   Map_MatrixXd_copy_matrix(struct C_Map_MatrixXd *dst,
                                    const struct C_MatrixXd *src);  
    void   Map_MatrixXd_set_coeff  (struct C_Map_MatrixXd *m,
                                    int i, int j, double coeff);
    double Map_MatrixXd_get_coeff  (const struct C_Map_MatrixXd *m,
                                    int i, int j);
    void   Map_MatrixXd_print      (const struct C_Map_MatrixXd *m);
    void   Map_MatrixXd_add        (const struct C_Map_MatrixXd *m1,
                                    const struct C_Map_MatrixXd *m2,
                                    struct C_Map_MatrixXd *result);  
    void   Map_MatrixXd_multiply   (const struct C_Map_MatrixXd *m1,
                                    const struct C_Map_MatrixXd *m2,
                                    struct C_Map_MatrixXd *result);
  
  #ifdef __cplusplus
  } // end extern "C"
  #endif