Fix build failures in matrix_power and matrix_exponential tests.

This fixes the static assertion complaining about double being
used in place of long double. This happened on MIPS32, where
double and long double have the same type representation.
This can be simulated on x86 as well if we pass -mlong-double-64
to g++.

1 files changed, 4 insertions, 3 deletions

diff --git a/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h b/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h
index 54037d58d..8aebcd67a 100644
--- a/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h
+++ b/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h
@@ -234,12 +234,13 @@ struct matrix_exp_computeUV<MatrixType, float>
 template <typename MatrixType>
 struct matrix_exp_computeUV<MatrixType, double>
 {
+  typedef typename NumTraits<typename traits<MatrixType>::Scalar>::Real RealScalar;
   template <typename ArgType>
   static void run(const ArgType& arg, MatrixType& U, MatrixType& V, int& squarings)
   {
     using std::frexp;
     using std::pow;
-    const double l1norm = arg.cwiseAbs().colwise().sum().maxCoeff();
+    const RealScalar l1norm = arg.cwiseAbs().colwise().sum().maxCoeff();
     squarings = 0;
     if (l1norm < 1.495585217958292e-002) {
       matrix_exp_pade3(arg, U, V);
@@ -250,10 +251,10 @@ struct matrix_exp_computeUV<MatrixType, double>
     } else if (l1norm < 2.097847961257068e+000) {
       matrix_exp_pade9(arg, U, V);
     } else {
-      const double maxnorm = 5.371920351148152;
+      const RealScalar maxnorm = 5.371920351148152;
       frexp(l1norm / maxnorm, &squarings);
       if (squarings < 0) squarings = 0;
-      MatrixType A = arg.unaryExpr(MatrixExponentialScalingOp<double>(squarings));
+      MatrixType A = arg.unaryExpr(MatrixExponentialScalingOp<RealScalar>(squarings));
       matrix_exp_pade13(A, U, V);
     }
   }