Updated the custom indexing code: we can now use any container that provides the [] operator to index a tensor. Added unit tests to validate the use of std::map and a few more types as valid custom index containers

1 files changed, 4 insertions, 4 deletions

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorMeta.h b/unsupported/Eigen/CXX11/src/Tensor/TensorMeta.h
index d1efc1a87..07735fa5f 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorMeta.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorMeta.h
@@ -82,15 +82,15 @@ namespace internal{
 
   template<typename IndexType, Index... Is>
   EIGEN_CONSTEXPR EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
-  array<Index,sizeof...(Is)> customIndices2Array(const IndexType & idx, numeric_list<Index,Is...>) {
-    return { idx(Is)... };
+  array<Index, sizeof...(Is)> customIndices2Array(IndexType& idx, numeric_list<Index, Is...>) {
+    return { idx[Is]... };
   }
 
   /** Make an array (for index/dimensions) out of a custom index */
   template<typename Index, int NumIndices, typename IndexType>
   EIGEN_CONSTEXPR EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
-  array<Index,NumIndices> customIndices2Array(const IndexType & idx) {
-    return customIndices2Array(idx, typename gen_numeric_list<Index,NumIndices>::type{});
+  array<Index, NumIndices> customIndices2Array(IndexType& idx) {
+    return customIndices2Array(idx, typename gen_numeric_list<Index, NumIndices>::type{});
   }