Add support for matrix sine, cosine, sinh and cosh.

2026-04-10 11:34:33 +08:00 · 2010-01-11 18:05:30 +00:00
parent a05d42616b
commit 65cd1c7639
8 changed files with 401 additions and 22 deletions
--- a/unsupported/Eigen/src/MatrixFunctions/StemFunction.h
+++ b/unsupported/Eigen/src/MatrixFunctions/StemFunction.h
@@ -0,0 +1,123 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2010 Jitse Niesen <jitse@maths.leeds.ac.uk>
+//
+// Eigen is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 3 of the License, or (at your option) any later version.
+//
+// Alternatively, you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License and a copy of the GNU General Public License along with
+// Eigen. If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef EIGEN_STEM_FUNCTION
+#define EIGEN_STEM_FUNCTION
+
+template <typename Scalar>
+struct ei_stem_function
+{
+  typedef std::complex<typename NumTraits<Scalar>::Real> ComplexScalar;
+  typedef ComplexScalar type(ComplexScalar, int);
+};
+
+/** \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
+
+#endif // EIGEN_STEM_FUNCTION