1 files changed, 4 insertions, 0 deletions
diff --git a/unsupported/Eigen/src/NonLinearOptimization/chkder.h b/unsupported/Eigen/src/NonLinearOptimization/chkder.h
index ad37c5029..db8ff7d6e 100644
--- a/unsupported/Eigen/src/NonLinearOptimization/chkder.h
+++ b/unsupported/Eigen/src/NonLinearOptimization/chkder.h
@@ -16,6 +16,10 @@ void chkder(
         Matrix< Scalar, Dynamic, 1 >  &err
         )
 {
+    using std::sqrt;
+    using std::abs;
+    using std::log;
+    
     typedef DenseIndex Index;
 
     const Scalar eps = sqrt(NumTraits<Scalar>::epsilon());