From d072fc4b1432b193d24e44d70885b636d4132405 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 10 Jan 2017 17:10:35 +0100
Subject: [PATCH] add writeable IndexedView

---
 Eigen/src/Core/DenseBase.h   | 66 ++++++++++++++++++++++++++++++++----
 Eigen/src/Core/IndexedView.h |  7 ++++
 test/indexed_view.cpp        | 15 ++++++++
 3 files changed, 81 insertions(+), 7 deletions(-)

diff --git a/Eigen/src/Core/DenseBase.h b/Eigen/src/Core/DenseBase.h
index 779cb4549..909fa0f12 100644
--- a/Eigen/src/Core/DenseBase.h
+++ b/Eigen/src/Core/DenseBase.h
@@ -558,27 +558,27 @@ template<typename Derived> class DenseBase
     EIGEN_DEVICE_FUNC void reverseInPlace();
 
     template<typename RowIndices, typename ColIndices>
-    struct IndexedViewType {
+    struct ConstIndexedViewType {
       typedef IndexedView<const Derived,typename internal::MakeIndexing<RowIndices>::type,typename internal::MakeIndexing<ColIndices>::type> type;
     };
 
     template<typename RowIndices, typename ColIndices>
     typename internal::enable_if<
-      !  (internal::traits<typename IndexedViewType<RowIndices,ColIndices>::type>::IsBlockAlike
+      !  (internal::traits<typename ConstIndexedViewType<RowIndices,ColIndices>::type>::IsBlockAlike
       || (internal::is_integral<RowIndices>::value && internal::is_integral<ColIndices>::value)),
-      typename IndexedViewType<RowIndices,ColIndices>::type >::type
+      typename ConstIndexedViewType<RowIndices,ColIndices>::type >::type
     operator()(const RowIndices& rowIndices, const ColIndices& colIndices) const {
-      return typename IndexedViewType<RowIndices,ColIndices>::type(
+      return typename ConstIndexedViewType<RowIndices,ColIndices>::type(
                 derived(), internal::make_indexing(rowIndices,derived().rows()), internal::make_indexing(colIndices,derived().cols()));
     }
 
     template<typename RowIndices, typename ColIndices>
     typename internal::enable_if<
-         internal::traits<typename IndexedViewType<RowIndices,ColIndices>::type>::IsBlockAlike
+         internal::traits<typename ConstIndexedViewType<RowIndices,ColIndices>::type>::IsBlockAlike
       && !(internal::is_integral<RowIndices>::value && internal::is_integral<ColIndices>::value),
-      typename internal::traits<typename IndexedViewType<RowIndices,ColIndices>::type>::BlockType>::type
+      typename internal::traits<typename ConstIndexedViewType<RowIndices,ColIndices>::type>::BlockType>::type
     operator()(const RowIndices& rowIndices, const ColIndices& colIndices) const {
-      typedef typename internal::traits<typename IndexedViewType<RowIndices,ColIndices>::type>::BlockType BlockType;
+      typedef typename internal::traits<typename ConstIndexedViewType<RowIndices,ColIndices>::type>::BlockType BlockType;
       typename internal::MakeIndexing<RowIndices>::type actualRowIndices = internal::make_indexing(rowIndices,derived().rows());
       typename internal::MakeIndexing<ColIndices>::type actualColIndices = internal::make_indexing(colIndices,derived().cols());
       return BlockType(derived(),
@@ -609,6 +609,58 @@ template<typename Derived> class DenseBase
                 derived(), rowIndices, colIndices);
     }
 
+    template<typename RowIndices, typename ColIndices>
+    struct IndexedViewType {
+      typedef IndexedView<Derived,typename internal::MakeIndexing<RowIndices>::type,typename internal::MakeIndexing<ColIndices>::type> type;
+    };
+
+    template<typename RowIndices, typename ColIndices>
+    typename internal::enable_if<
+      !  (internal::traits<typename IndexedViewType<RowIndices,ColIndices>::type>::IsBlockAlike
+      || (internal::is_integral<RowIndices>::value && internal::is_integral<ColIndices>::value)),
+      typename IndexedViewType<RowIndices,ColIndices>::type >::type
+    operator()(const RowIndices& rowIndices, const ColIndices& colIndices) {
+      return typename IndexedViewType<RowIndices,ColIndices>::type(
+                derived(), internal::make_indexing(rowIndices,derived().rows()), internal::make_indexing(colIndices,derived().cols()));
+    }
+
+    template<typename RowIndices, typename ColIndices>
+    typename internal::enable_if<
+         internal::traits<typename IndexedViewType<RowIndices,ColIndices>::type>::IsBlockAlike
+      && !(internal::is_integral<RowIndices>::value && internal::is_integral<ColIndices>::value),
+      typename internal::traits<typename IndexedViewType<RowIndices,ColIndices>::type>::BlockType>::type
+    operator()(const RowIndices& rowIndices, const ColIndices& colIndices) {
+      typedef typename internal::traits<typename IndexedViewType<RowIndices,ColIndices>::type>::BlockType BlockType;
+      typename internal::MakeIndexing<RowIndices>::type actualRowIndices = internal::make_indexing(rowIndices,derived().rows());
+      typename internal::MakeIndexing<ColIndices>::type actualColIndices = internal::make_indexing(colIndices,derived().cols());
+      return BlockType(derived(),
+                       internal::first(actualRowIndices),
+                       internal::first(actualColIndices),
+                       internal::size(actualRowIndices),
+                       internal::size(actualColIndices));
+    }
+
+    template<typename RowIndicesT, std::size_t RowIndicesN, typename ColIndices>
+    IndexedView<Derived,const RowIndicesT (&)[RowIndicesN],typename internal::MakeIndexing<ColIndices>::type>
+    operator()(const RowIndicesT (&rowIndices)[RowIndicesN], const ColIndices& colIndices) {
+      return IndexedView<Derived,const RowIndicesT (&)[RowIndicesN],typename internal::MakeIndexing<ColIndices>::type>(
+                derived(), rowIndices, internal::make_indexing(colIndices,derived().cols()));
+    }
+
+    template<typename RowIndices, typename ColIndicesT, std::size_t ColIndicesN>
+    IndexedView<Derived,typename internal::MakeIndexing<RowIndices>::type, const ColIndicesT (&)[ColIndicesN]>
+    operator()(const RowIndices& rowIndices, const ColIndicesT (&colIndices)[ColIndicesN]) {
+      return IndexedView<Derived,typename internal::MakeIndexing<RowIndices>::type,const ColIndicesT (&)[ColIndicesN]>(
+                derived(), internal::make_indexing(rowIndices,derived().rows()), colIndices);
+    }
+
+    template<typename RowIndicesT, std::size_t RowIndicesN, typename ColIndicesT, std::size_t ColIndicesN>
+    IndexedView<Derived,const RowIndicesT (&)[RowIndicesN], const ColIndicesT (&)[ColIndicesN]>
+    operator()(const RowIndicesT (&rowIndices)[RowIndicesN], const ColIndicesT (&colIndices)[ColIndicesN]) {
+      return IndexedView<Derived,const RowIndicesT (&)[RowIndicesN],const ColIndicesT (&)[ColIndicesN]>(
+                derived(), rowIndices, colIndices);
+    }
+
 #define EIGEN_CURRENT_STORAGE_BASE_CLASS Eigen::DenseBase
 #define EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 #define EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(COND)
diff --git a/Eigen/src/Core/IndexedView.h b/Eigen/src/Core/IndexedView.h
index 5aaf5b4e0..81ff53758 100644
--- a/Eigen/src/Core/IndexedView.h
+++ b/Eigen/src/Core/IndexedView.h
@@ -104,6 +104,7 @@ class IndexedView : public IndexedViewImpl<XprType, RowIndices, ColIndices, type
 public:
   typedef typename IndexedViewImpl<XprType, RowIndices, ColIndices, typename internal::traits<XprType>::StorageKind>::Base Base;
   EIGEN_GENERIC_PUBLIC_INTERFACE(IndexedView)
+  EIGEN_INHERIT_ASSIGNMENT_OPERATORS(IndexedView)
 
   typedef typename internal::ref_selector<XprType>::non_const_type MatrixTypeNested;
   typedef typename internal::remove_all<XprType>::type NestedExpression;
@@ -180,6 +181,12 @@ struct unary_evaluator<IndexedView<ArgType, RowIndices, ColIndices>, IndexBased>
     return m_argImpl.coeff(m_xpr.rowIndices()[row], m_xpr.colIndices()[col]);
   }
 
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  Scalar& coeffRef(Index row, Index col)
+  {
+    return m_argImpl.coeffRef(m_xpr.rowIndices()[row], m_xpr.colIndices()[col]);
+  }
+
 protected:
 
   evaluator<ArgType> m_argImpl;
diff --git a/test/indexed_view.cpp b/test/indexed_view.cpp
index fde3ee8f9..42d136847 100644
--- a/test/indexed_view.cpp
+++ b/test/indexed_view.cpp
@@ -168,6 +168,12 @@ void check_indexed_view()
 
   // Check fall-back to Block
   {
+    VERIFY( is_same_type(A.col(0), A(all,0)) );
+    VERIFY( is_same_type(A.row(0), A(0,all)) );
+    VERIFY( is_same_type(A.block(0,0,2,2), A(seqN(0,2),seq(0,1))) );
+    VERIFY( is_same_type(A.middleRows(2,4), A(seqN(2,4),all)) );
+    VERIFY( is_same_type(A.middleCols(2,4), A(all,seqN(2,4))) );
+
     const ArrayXXi& cA(A);
     VERIFY( is_same_type(cA.col(0), cA(all,0)) );
     VERIFY( is_same_type(cA.row(0), cA(0,all)) );
@@ -176,6 +182,15 @@ void check_indexed_view()
     VERIFY( is_same_type(cA.middleCols(2,4), cA(all,seqN(2,4))) );
   }
 
+  ArrayXXi A1=A, A2 = ArrayXXi::Random(4,4);
+  ArrayXi range25(4); range25 << 3,2,4,5;
+  A1(seqN(3,4),seq(2,5)) = A2;
+  VERIFY_IS_APPROX( A1.block(3,2,4,4), A2 );
+  A1 = A;
+  A2.setOnes();
+  A1(seq(6,3,-1),range25) = A2;
+  VERIFY_IS_APPROX( A1.block(3,2,4,4), A2 );
+
 #if EIGEN_HAS_CXX11
   VERIFY( (A(all, std::array<int,4>{{1,3,2,4}})).ColsAtCompileTime == 4);