diff --git a/include/ceres/internal/eigen.h b/include/ceres/internal/eigen.h
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+// 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_INTERNAL_EIGEN_H_
+#define CERES_INTERNAL_EIGEN_H_
+
+#include "Eigen/Core"
+
+namespace ceres {
+
+typedef Eigen::Matrix<double, Eigen::Dynamic, 1> Vector;
+typedef Eigen::Matrix<double,
+                      Eigen::Dynamic,
+                      Eigen::Dynamic,
+                      Eigen::RowMajor> Matrix;
+typedef Eigen::Map<Vector> VectorRef;
+typedef Eigen::Map<Matrix> MatrixRef;
+typedef Eigen::Map<const Vector> ConstVectorRef;
+typedef Eigen::Map<const Matrix> ConstMatrixRef;
+
+// Column major matrices for DenseSparseMatrix/DenseQRSolver
+typedef Eigen::Matrix<double,
+                      Eigen::Dynamic,
+                      Eigen::Dynamic,
+                      Eigen::ColMajor> ColMajorMatrix;
+
+typedef Eigen::Map<ColMajorMatrix, 0,
+                   Eigen::Stride<Eigen::Dynamic, 1>> ColMajorMatrixRef;
+
+typedef Eigen::Map<const ColMajorMatrix,
+                   0,
+                   Eigen::Stride<Eigen::Dynamic, 1>> ConstColMajorMatrixRef;
+
+// 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 {
+  typedef Eigen::Matrix<double,
+                        num_rows,
+                        num_cols,
+                        num_cols == 1 ? Eigen::ColMajor : Eigen::RowMajor>
+      Matrix;
+
+  typedef Eigen::Map<Matrix> MatrixRef;
+  typedef Eigen::Map<const Matrix> ConstMatrixRef;
+  typedef Eigen::Matrix<double, num_rows, 1> Vector;
+  typedef Eigen::Map<Eigen::Matrix<double, num_rows, 1>> VectorRef;
+  typedef Eigen::Map<const Eigen::Matrix<double, num_rows, 1>> ConstVectorRef;
+};
+
+}  // namespace ceres
+
+#endif  // CERES_INTERNAL_EIGEN_H_