From 8456bbbadb8175a9e20d804b61de4da7d951d7f7 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Wed, 18 May 2016 16:53:28 +0200
Subject: [PATCH] bug #1224: fix regression in (dense*dense).sparseView() by
 specializing evaluator<SparseView<Product>> for sparse products only.

---
 Eigen/src/SparseCore/SparseProduct.h | 12 ++++++------
 test/sparse_basic.cpp                |  6 ++++++
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/Eigen/src/SparseCore/SparseProduct.h b/Eigen/src/SparseCore/SparseProduct.h
index cbd0db71b..b23003bb1 100644
--- a/Eigen/src/SparseCore/SparseProduct.h
+++ b/Eigen/src/SparseCore/SparseProduct.h
@@ -131,14 +131,14 @@ struct Assignment<DstXprType, Product<Lhs,Rhs,AliasFreeProduct>, internal::sub_a
 };
 
 template<typename Lhs, typename Rhs, int Options>
-struct evaluator<SparseView<Product<Lhs, Rhs, Options> > > 
+struct unary_evaluator<SparseView<Product<Lhs, Rhs, Options> >, IteratorBased>
  : public evaluator<typename Product<Lhs, Rhs, DefaultProduct>::PlainObject>
 {
   typedef SparseView<Product<Lhs, Rhs, Options> > XprType;
   typedef typename XprType::PlainObject PlainObject;
   typedef evaluator<PlainObject> Base;
-  
-  explicit evaluator(const XprType& xpr)
+
+  explicit unary_evaluator(const XprType& xpr)
     : m_result(xpr.rows(), xpr.cols())
   {
     using std::abs;
@@ -147,13 +147,13 @@ struct evaluator<SparseView<Product<Lhs, Rhs, Options> > >
     typedef typename nested_eval<Rhs,Dynamic>::type RhsNested;
     LhsNested lhsNested(xpr.nestedExpression().lhs());
     RhsNested rhsNested(xpr.nestedExpression().rhs());
-    
+
     internal::sparse_sparse_product_with_pruning_selector<typename remove_all<LhsNested>::type,
                                                           typename remove_all<RhsNested>::type, PlainObject>::run(lhsNested,rhsNested,m_result,
                                                                                                                   abs(xpr.reference())*xpr.epsilon());
   }
-  
-protected:  
+
+protected:
   PlainObject m_result;
 };
 
diff --git a/test/sparse_basic.cpp b/test/sparse_basic.cpp
index 387b817b5..f28c5b80e 100644
--- a/test/sparse_basic.cpp
+++ b/test/sparse_basic.cpp
@@ -372,6 +372,12 @@ template<typename SparseMatrixType> void sparse_basic(const SparseMatrixType& re
     SparseMatrixType m2(rows, rows);
     initSparse<Scalar>(density, refMat2, m2);
     VERIFY_IS_APPROX(m2.eval(), refMat2.sparseView().eval());
+
+    // sparse view on expressions:
+    VERIFY_IS_APPROX((s1*m2).eval(), (s1*refMat2).sparseView().eval());
+    VERIFY_IS_APPROX((m2+m2).eval(), (refMat2+refMat2).sparseView().eval());
+    VERIFY_IS_APPROX((m2*m2).eval(), (refMat2.lazyProduct(refMat2)).sparseView().eval());
+    VERIFY_IS_APPROX((m2*m2).eval(), (refMat2*refMat2).sparseView().eval());
   }
 
   // test diagonal