Squashed 'third_party/ceres/' content from commit e51e9b4

Change-Id: I763587619d57e594d3fa158dc3a7fe0b89a1743b
git-subtree-dir: third_party/ceres
git-subtree-split: e51e9b46f6ca88ab8b2266d0e362771db6d98067
diff --git a/include/ceres/crs_matrix.h b/include/ceres/crs_matrix.h
new file mode 100644
index 0000000..23687c4
--- /dev/null
+++ b/include/ceres/crs_matrix.h
@@ -0,0 +1,86 @@
+// 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:
+//
+// * Redistributions of source code must retain the above copyright notice,
+//   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
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// 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_