From 4beb447e27baaa19081e835bd6aba76e9b02cc67 Mon Sep 17 00:00:00 2001
From: Benoit Steiner <benoit.steiner.goog@gmail.com>
Date: Fri, 22 Jan 2016 14:37:26 -0800
Subject: [PATCH] Created a mechanism to enable contraction mappers to
 determine the best blocking strategy.

---
 unsupported/Eigen/CXX11/Tensor                |  1 +
 .../src/Tensor/TensorContractionBlocking.h    | 58 +++++++++++++++++++
 2 files changed, 59 insertions(+)
 create mode 100644 unsupported/Eigen/CXX11/src/Tensor/TensorContractionBlocking.h

diff --git a/unsupported/Eigen/CXX11/Tensor b/unsupported/Eigen/CXX11/Tensor
index 1c5734383..b4f860c41 100644
--- a/unsupported/Eigen/CXX11/Tensor
+++ b/unsupported/Eigen/CXX11/Tensor
@@ -89,6 +89,7 @@ typedef unsigned __int64 uint64_t;
 #include "src/Tensor/TensorArgMax.h"
 #include "src/Tensor/TensorConcatenation.h"
 #include "src/Tensor/TensorContractionMapper.h"
+#include "src/Tensor/TensorContractionBlocking.h"
 #include "src/Tensor/TensorContraction.h"
 #include "src/Tensor/TensorContractionThreadPool.h"
 #include "src/Tensor/TensorContractionCuda.h"
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorContractionBlocking.h b/unsupported/Eigen/CXX11/src/Tensor/TensorContractionBlocking.h
new file mode 100644
index 000000000..78ed5038f
--- /dev/null
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorContractionBlocking.h
@@ -0,0 +1,58 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2014 Benoit Steiner <benoit.steiner.goog@gmail.com>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#ifndef EIGEN_CXX11_TENSOR_TENSOR_CONTRACTION_BLOCKING_H
+#define EIGEN_CXX11_TENSOR_TENSOR_CONTRACTION_BLOCKING_H
+
+
+namespace Eigen {
+namespace internal {
+
+enum {
+  ShardByRow = 0,
+  ShardByCol = 1
+};
+
+
+// Default Blocking Strategy
+template <typename LhsMapper, typename RhsMapper, typename Index, int ShardingType=ShardByCol>
+class TensorContractionBlocking {
+ public:
+
+  typedef typename LhsMapper::Scalar LhsScalar;
+  typedef typename RhsMapper::Scalar RhsScalar;
+
+  TensorContractionBlocking(Index k, Index m, Index n, Index num_threads = 1) :
+      kc_(k), mc_(m), nc_(n)
+  {
+    if (ShardingType == ShardByCol) {
+      computeProductBlockingSizes<LhsScalar, RhsScalar, 1>(kc_, mc_, nc_, num_threads);
+    }
+    else {
+      if (kc_ && mc_ && nc_) {
+        mc_ = (((m / num_threads) + 15) / 16) * 16;
+      }
+    }
+  }
+
+  EIGEN_ALWAYS_INLINE Index kc() const { return kc_; }
+  EIGEN_ALWAYS_INLINE Index mc() const { return mc_; }
+  EIGEN_ALWAYS_INLINE Index nc() const { return nc_; }
+
+ private:
+  Index kc_;
+  Index mc_;
+  Index nc_;
+};
+
+
+} // end namespace internal
+} // end namespace Eigen
+
+#endif // EIGEN_CXX11_TENSOR_TENSOR_CONTRACTION_BLOCKING_H