From 40bb98e76acbe6e077903e15896c100ee6cced39 Mon Sep 17 00:00:00 2001
From: Benoit Steiner <benoit.steiner.goog@gmail.com>
Date: Thu, 10 Jul 2014 11:29:51 -0700
Subject: [PATCH] Added primitives to compare tensor dimensions

---
 .../Eigen/CXX11/src/Tensor/TensorDimensions.h | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorDimensions.h b/unsupported/Eigen/CXX11/src/Tensor/TensorDimensions.h
index 3e5687915..3b169a06f 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorDimensions.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorDimensions.h
@@ -210,6 +210,60 @@ struct DSizes : array<DenseIndex, NumDims> {
 };
 
 
+namespace internal {
+
+template <typename DenseIndex, std::size_t NumDims> struct array_size<const DSizes<DenseIndex, NumDims> > {
+  static const size_t value = NumDims;
+};
+template <typename DenseIndex, std::size_t NumDims> struct array_size<DSizes<DenseIndex, NumDims> > {
+  static const size_t value = NumDims;
+};
+#ifndef EIGEN_EMULATE_CXX11_META_H
+template <typename std::size_t... Indices> struct array_size<const Sizes<Indices...> > {
+static const size_t value = Sizes<Indices...>::count;
+};
+template <typename std::size_t... Indices> struct array_size<Sizes<Indices...> > {
+static const size_t value = Sizes<Indices...>::count;
+};
+#else
+template <std::size_t V1, std::size_t V2, std::size_t V3, std::size_t V4, std::size_t V5> struct array_size<const Sizes<V1,V2,V3,V4,V5> > {
+  static const size_t value = Sizes<V1,V2,V3,V4,V5>::count;
+};
+template <std::size_t V1, std::size_t V2, std::size_t V3, std::size_t V4, std::size_t V5> struct array_size<Sizes<V1,V2,V3,V4,V5> > {
+  static const size_t value = Sizes<V1,V2,V3,V4,V5>::count;
+};
+template <std::size_t n, std::size_t V1, std::size_t V2, std::size_t V3, std::size_t V4, std::size_t V5> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE std::size_t array_get(const Sizes<V1,V2,V3,V4,V5>& a) {
+  return get<n, typename Sizes<V1,V2,V3,V4,V5>::Base>::value;
+};
+
+#endif
+
+
+template <typename Dims1, typename Dims2, size_t n>
+struct sizes_match_up_to_dim {
+  static inline bool run(Dims1& dims1, Dims2& dims2) {
+    return (array_get<n>(dims1) == array_get<n>(dims2)) &
+        sizes_match_up_to_dim<Dims1, Dims2, n-1>::run(dims1, dims2);
+  }
+};
+template <typename Dims1, typename Dims2>
+struct sizes_match_up_to_dim<Dims1, Dims2, 0> {
+  static inline bool run(Dims1& dims1, Dims2& dims2) {
+    return (array_get<0>(dims1) == array_get<0>(dims2));
+  }
+};
+
+template <typename Dims1, typename Dims2>
+bool dimensions_match(Dims1& dims1, Dims2& dims2) {
+  if (array_size<Dims1>::value != array_size<Dims2>::value) {
+    return false;
+  }
+  return sizes_match_up_to_dim<Dims1, Dims2, array_size<Dims1>::value-1>::run(dims1, dims2);
+}
+
+} // end namespace internal
+
+
 } // end namespace Eigen
 
 #endif // EIGEN_CXX11_TENSOR_TENSOR_DIMENSIONS_H