From eaf4b98180d7606abba69133e39e23537ced79e5 Mon Sep 17 00:00:00 2001
From: Benoit Steiner <benoit.steiner.goog@gmail.com>
Date: Tue, 20 Oct 2015 11:41:22 -0700
Subject: Added support for boolean reductions (ie 'and' & 'or' reductions)

---
 unsupported/Eigen/CXX11/src/Tensor/README.md       | 13 +++++++++++
 unsupported/Eigen/CXX11/src/Tensor/TensorBase.h    | 26 +++++++++++++++++++++
 .../Eigen/CXX11/src/Tensor/TensorFunctors.h        | 27 ++++++++++++++++++++++
 3 files changed, 66 insertions(+)

(limited to 'unsupported/Eigen')

diff --git a/unsupported/Eigen/CXX11/src/Tensor/README.md b/unsupported/Eigen/CXX11/src/Tensor/README.md
index 87e57cebb..407485090 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/README.md
+++ b/unsupported/Eigen/CXX11/src/Tensor/README.md
@@ -1149,6 +1149,19 @@ are the smallest of the reduced values.
 Reduce a tensor using the prod() operator.  The resulting values
 are the product of the reduced values.
 
+### &lt;Operation&gt; all(const Dimensions& new_dims)
+### &lt;Operation&gt; all()
+Reduce a tensor using the all() operator.  Casts tensor to bool and then checks
+whether all elements are true.  Runs through all elements rather than
+short-circuiting, so may be significantly inefficient.
+
+### &lt;Operation&gt; any(const Dimensions& new_dims)
+### &lt;Operation&gt; any()
+Reduce a tensor using the any() operator.  Casts tensor to bool and then checks
+whether any element is true.  Runs through all elements rather than
+short-circuiting, so may be significantly inefficient.
+
+
 ### &lt;Operation&gt; reduce(const Dimensions& new_dims, const Reducer& reducer)
 
 Reduce a tensor using a user-defined reduction operator.  See ```SumReducer```
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h b/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h
index 477e4a174..c00f67950 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h
@@ -363,6 +363,32 @@ class TensorBase<Derived, ReadOnlyAccessors>
       return TensorReductionOp<internal::MinReducer<CoeffReturnType>, const DimensionList<Index, NumDimensions>, const Derived>(derived(), in_dims, internal::MinReducer<CoeffReturnType>());
     }
 
+    template <typename Dims> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+    const TensorReductionOp<internal::AndReducer, const Dims, const TensorConversionOp<bool, const Derived> >
+    all(const Dims& dims) const {
+      return cast<bool>().reduce(dims, internal::AndReducer());
+    }
+
+    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+    const TensorReductionOp<internal::AndReducer, const DimensionList<Index, NumDimensions>, const TensorConversionOp<bool, const Derived> >
+    all() const {
+      DimensionList<Index, NumDimensions> in_dims;
+      return cast<bool>().reduce(in_dims, internal::AndReducer());
+    }
+
+    template <typename Dims> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+    const TensorReductionOp<internal::OrReducer, const Dims, const TensorConversionOp<bool, const Derived> >
+    any(const Dims& dims) const {
+      return cast<bool>().reduce(dims, internal::OrReducer());
+    }
+
+    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+    const TensorReductionOp<internal::OrReducer, const DimensionList<Index, NumDimensions>, const TensorConversionOp<bool, const Derived> >
+    any() const {
+      DimensionList<Index, NumDimensions> in_dims;
+      return cast<bool>().reduce(in_dims, internal::OrReducer());
+    }
+
    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
     const TensorTupleReducerOp<
       internal::ArgMaxTupleReducer<Tuple<Index, CoeffReturnType> >,
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorFunctors.h b/unsupported/Eigen/CXX11/src/Tensor/TensorFunctors.h
index ed259399b..a98c6a2e3 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorFunctors.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorFunctors.h
@@ -219,6 +219,33 @@ template <typename T> struct ProdReducer
 };
 
 
+struct AndReducer
+{
+  static const bool PacketAccess = false;
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void reduce(bool t, bool* accum) const {
+    *accum = *accum && t;
+  }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool initialize() const {
+    return true;
+  }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool finalize(bool accum) const {
+    return accum;
+  }
+};
+
+struct OrReducer {
+  static const bool PacketAccess = false;
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void reduce(bool t, bool* accum) const {
+    *accum = *accum || t;
+  }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool initialize() const {
+    return false;
+  }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool finalize(bool accum) const {
+    return accum;
+  }
+};
+
 // Argmin/Argmax reducers
 template <typename T> struct ArgMaxTupleReducer
 {
-- 
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