Squashed 'third_party/eigen/' content from commit 61d72f6
Change-Id: Iccc90fa0b55ab44037f018046d2fcffd90d9d025
git-subtree-dir: third_party/eigen
git-subtree-split: 61d72f6383cfa842868c53e30e087b0258177257
diff --git a/unsupported/Eigen/src/MatrixFunctions/StemFunction.h b/unsupported/Eigen/src/MatrixFunctions/StemFunction.h
new file mode 100644
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+++ b/unsupported/Eigen/src/MatrixFunctions/StemFunction.h
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+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2010 Jitse Niesen <jitse@maths.leeds.ac.uk>
+//
+// 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/.
+
+#ifndef EIGEN_STEM_FUNCTION
+#define EIGEN_STEM_FUNCTION
+
+namespace Eigen {
+
+/** \ingroup MatrixFunctions_Module
+ * \brief Stem functions corresponding to standard mathematical functions.
+ */
+template <typename Scalar>
+class StdStemFunctions
+{
+ public:
+
+ /** \brief The exponential function (and its derivatives). */
+ static Scalar exp(Scalar x, int)
+ {
+ return std::exp(x);
+ }
+
+ /** \brief Cosine (and its derivatives). */
+ static Scalar cos(Scalar x, int n)
+ {
+ Scalar res;
+ switch (n % 4) {
+ case 0:
+ res = std::cos(x);
+ break;
+ case 1:
+ res = -std::sin(x);
+ break;
+ case 2:
+ res = -std::cos(x);
+ break;
+ case 3:
+ res = std::sin(x);
+ break;
+ }
+ return res;
+ }
+
+ /** \brief Sine (and its derivatives). */
+ static Scalar sin(Scalar x, int n)
+ {
+ Scalar res;
+ switch (n % 4) {
+ case 0:
+ res = std::sin(x);
+ break;
+ case 1:
+ res = std::cos(x);
+ break;
+ case 2:
+ res = -std::sin(x);
+ break;
+ case 3:
+ res = -std::cos(x);
+ break;
+ }
+ return res;
+ }
+
+ /** \brief Hyperbolic cosine (and its derivatives). */
+ static Scalar cosh(Scalar x, int n)
+ {
+ Scalar res;
+ switch (n % 2) {
+ case 0:
+ res = std::cosh(x);
+ break;
+ case 1:
+ res = std::sinh(x);
+ break;
+ }
+ return res;
+ }
+
+ /** \brief Hyperbolic sine (and its derivatives). */
+ static Scalar sinh(Scalar x, int n)
+ {
+ Scalar res;
+ switch (n % 2) {
+ case 0:
+ res = std::sinh(x);
+ break;
+ case 1:
+ res = std::cosh(x);
+ break;
+ }
+ return res;
+ }
+
+}; // end of class StdStemFunctions
+
+} // end namespace Eigen
+
+#endif // EIGEN_STEM_FUNCTION