// Ceres Solver - A fast non-linear least squares minimizer

// Copyright 2015 Google Inc. All rights reserved.

// http://ceres-solver.org/

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//

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//   this list of conditions and the following disclaimer.

// * Redistributions in binary form must reproduce the above copyright notice,

//   this list of conditions and the following disclaimer in the documentation

//   and/or other materials provided with the distribution.

// * Neither the name of Google Inc. nor the names of its contributors may be

//   used to endorse or promote products derived from this software without

//   specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

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// Author: sameeragarwal@google.com (Sameer Agarwal)

#ifndef CERES_PUBLIC_CRS_MATRIX_H_

#define CERES_PUBLIC_CRS_MATRIX_H_

#include <vector>

#include "ceres/internal/port.h"

#include "ceres/internal/disable_warnings.h"

namespace ceres {

// A compressed row sparse matrix used primarily for communicating the

// Jacobian matrix to the user.

struct CERES_EXPORT CRSMatrix {

  CRSMatrix() : num_rows(0), num_cols(0) {}

  int num_rows;

  int num_cols;

  // A compressed row matrix stores its contents in three arrays,

  // rows, cols and values.

  //

  // rows is a num_rows + 1 sized array that points into the cols and

  // values array. For each row i:

  //

  // cols[rows[i]] ... cols[rows[i + 1] - 1] are the indices of the

  // non-zero columns of row i.

  //

  // values[rows[i]] .. values[rows[i + 1] - 1] are the values of the

  // corresponding entries.

  //

  // cols and values contain as many entries as there are non-zeros in

  // the matrix.

  //

  // e.g, consider the 3x4 sparse matrix

  //

  //  [ 0 10  0  4 ]

  //  [ 0  2 -3  2 ]

  //  [ 1  2  0  0 ]

  //

  // The three arrays will be:

  //

  //

  //            -row0-  ---row1---  -row2-

  //  rows   = [ 0,      2,          5,     7]

  //  cols   = [ 1,  3,  1,  2,  3,  0,  1]

  //  values = [10,  4,  2, -3,  2,  1,  2]

  std::vector<int> cols;

  std::vector<int> rows;

  std::vector<double> values;

};

}  // namespace ceres

#include "ceres/internal/reenable_warnings.h"

#endif  // CERES_PUBLIC_CRS_MATRIX_H_