From 446001ef51be920649cb4f3c07848967b6788532 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Wed, 24 Sep 2014 09:39:09 +0200
Subject: [PATCH] Fix nested_eval<Product<> > which wrongly returned a
 Product<> expression

---
 Eigen/src/Core/Inverse.h           |  3 +--
 Eigen/src/Core/ProductEvaluators.h | 10 +++++++---
 test/geo_orthomethods.cpp          |  5 ++++-
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/Eigen/src/Core/Inverse.h b/Eigen/src/Core/Inverse.h
index 706796b78..f3b0dff87 100644
--- a/Eigen/src/Core/Inverse.h
+++ b/Eigen/src/Core/Inverse.h
@@ -25,8 +25,7 @@ struct traits<Inverse<XprType> >
   typedef typename XprType::PlainObject PlainObject;
   typedef traits<PlainObject> BaseTraits;
   enum {
-    Flags = BaseTraits::Flags & RowMajorBit,
-    CoeffReadCost = Dynamic
+    Flags = BaseTraits::Flags & RowMajorBit
   };
 };
 
diff --git a/Eigen/src/Core/ProductEvaluators.h b/Eigen/src/Core/ProductEvaluators.h
index 69e569908..c944ec9fc 100644
--- a/Eigen/src/Core/ProductEvaluators.h
+++ b/Eigen/src/Core/ProductEvaluators.h
@@ -97,11 +97,12 @@ struct product_evaluator<Product<Lhs, Rhs, DefaultProduct>, ProductTag, LhsShape
   : public evaluator<typename Product<Lhs, Rhs, DefaultProduct>::PlainObject>::type
 {
   typedef Product<Lhs, Rhs, DefaultProduct> XprType;
-//   enum {
-//     CoeffReadCost = 0 // FIXME why is it needed? (this was already the case before the evaluators, see traits<ProductBase>)
-//   };
   typedef typename XprType::PlainObject PlainObject;
   typedef typename evaluator<PlainObject>::type Base;
+  enum {
+    Flags = Base::Flags | EvalBeforeNestingBit
+//     CoeffReadCost = 0 // FIXME why is it needed? (this was already the case before the evaluators, see traits<ProductBase>)
+  };
 
   explicit product_evaluator(const XprType& xpr)
     : m_result(xpr.rows(), xpr.cols())
@@ -508,6 +509,9 @@ struct product_evaluator<Product<Lhs, Rhs, DefaultProduct>, LazyCoeffBasedProduc
   typedef Product<Lhs, Rhs, DefaultProduct> XprType;
   typedef Product<Lhs, Rhs, LazyProduct> BaseProduct;
   typedef product_evaluator<BaseProduct, CoeffBasedProductMode, DenseShape, DenseShape, typename Lhs::Scalar, typename Rhs::Scalar > Base;
+  enum {
+    Flags = Base::Flags | EvalBeforeNestingBit
+  };
   explicit product_evaluator(const XprType& xpr)
     : Base(BaseProduct(xpr.lhs(),xpr.rhs()))
   {}
diff --git a/test/geo_orthomethods.cpp b/test/geo_orthomethods.cpp
index 7f8beb205..e178df257 100644
--- a/test/geo_orthomethods.cpp
+++ b/test/geo_orthomethods.cpp
@@ -39,7 +39,10 @@ template<typename Scalar> void orthomethods_3()
          (v0.cross(v1)).normalized(),
          (v0.cross(v1).cross(v0)).normalized();
   VERIFY(mat3.isUnitary());
-
+  
+  mat3.setRandom();
+  VERIFY_IS_APPROX(v0.cross(mat3*v1), -(mat3*v1).cross(v0));
+  VERIFY_IS_APPROX(v0.cross(mat3.lazyProduct(v1)), -(mat3.lazyProduct(v1)).cross(v0));
 
   // colwise/rowwise cross product
   mat3.setRandom();