From 63de19c0004933c7b2b1e418292b9f2ae6c138f4 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Mon, 30 Jan 2017 13:55:27 +0100
Subject: [PATCH] bug #1380: fix matrix exponential with Map<>

---
 .../Eigen/src/MatrixFunctions/MatrixExponential.h | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h b/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h
index 4bb1852b6..9ad2b9cc8 100644
--- a/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h
+++ b/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h
@@ -204,7 +204,8 @@ struct matrix_exp_computeUV
 template <typename MatrixType>
 struct matrix_exp_computeUV<MatrixType, float>
 {
-  static void run(const MatrixType& arg, MatrixType& U, MatrixType& V, int& squarings)
+  template <typename ArgType>
+  static void run(const ArgType& arg, MatrixType& U, MatrixType& V, int& squarings)
   {
     using std::frexp;
     using std::pow;
@@ -227,7 +228,8 @@ struct matrix_exp_computeUV<MatrixType, float>
 template <typename MatrixType>
 struct matrix_exp_computeUV<MatrixType, double>
 {
-  static void run(const MatrixType& arg, MatrixType& U, MatrixType& V, int& squarings)
+  template <typename ArgType>
+  static void run(const ArgType& arg, MatrixType& U, MatrixType& V, int& squarings)
   {
     using std::frexp;
     using std::pow;
@@ -254,7 +256,8 @@ struct matrix_exp_computeUV<MatrixType, double>
 template <typename MatrixType>
 struct matrix_exp_computeUV<MatrixType, long double>
 {
-  static void run(const MatrixType& arg, MatrixType& U, MatrixType& V, int& squarings)
+  template <typename ArgType>
+  static void run(const ArgType& arg, MatrixType& U, MatrixType& V, int& squarings)
   {
 #if   LDBL_MANT_DIG == 53   // double precision
     matrix_exp_computeUV<MatrixType, double>::run(arg, U, V, squarings);
@@ -351,11 +354,11 @@ void matrix_exp_compute(const MatrixType& arg, ResultType &result)
     return;
   }
 #endif
-  MatrixType U, V;
+  typename MatrixType::PlainObject U, V;
   int squarings; 
   matrix_exp_computeUV<MatrixType>::run(arg, U, V, squarings); // Pade approximant is (U+V) / (-U+V)
-  MatrixType numer = U + V;   
-  MatrixType denom = -U + V;
+  typename MatrixType::PlainObject numer = U + V;
+  typename MatrixType::PlainObject denom = -U + V;
   result = denom.partialPivLu().solve(numer);
   for (int i=0; i<squarings; i++)
     result *= result;   // undo scaling by repeated squaring