From 73f692d16b544d619c2234259f4086cc93c577df Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 27 Oct 2015 11:01:37 +0100
Subject: [PATCH] Fix ambiguous instantiation

---
 Eigen/src/SparseCore/SparseProduct.h | 75 +++++++++++++++++++++-------
 test/sparse_basic.cpp                |  2 +-
 test/sparse_product.cpp              |  4 ++
 3 files changed, 62 insertions(+), 19 deletions(-)

diff --git a/Eigen/src/SparseCore/SparseProduct.h b/Eigen/src/SparseCore/SparseProduct.h
index 26680b7a7..ea2c3a8a3 100644
--- a/Eigen/src/SparseCore/SparseProduct.h
+++ b/Eigen/src/SparseCore/SparseProduct.h
@@ -39,6 +39,34 @@ struct generic_product_impl<Lhs, Rhs, SparseShape, SparseShape, ProductType>
 {
   template<typename Dest>
   static void evalTo(Dest& dst, const Lhs& lhs, const Rhs& rhs)
+  {
+    evalTo(dst, lhs, rhs, typename evaluator_traits<Dest>::Shape());
+  }
+
+  // dense += sparse * sparse
+  template<typename Dest,typename ActualLhs>
+  static void addTo(Dest& dst, const ActualLhs& lhs, const Rhs& rhs, int* = typename enable_if<is_same<typename evaluator_traits<Dest>::Shape,DenseShape>::value,int*>::type(0) )
+  {
+    typedef typename nested_eval<ActualLhs,Dynamic>::type LhsNested;
+    typedef typename nested_eval<Rhs,Dynamic>::type RhsNested;
+    LhsNested lhsNested(lhs);
+    RhsNested rhsNested(rhs);
+    internal::sparse_sparse_to_dense_product_selector<typename remove_all<LhsNested>::type,
+                                                      typename remove_all<RhsNested>::type, Dest>::run(lhsNested,rhsNested,dst);
+  }
+
+  // dense -= sparse * sparse
+  template<typename Dest>
+  static void subTo(Dest& dst, const Lhs& lhs, const Rhs& rhs, int* = typename enable_if<is_same<typename evaluator_traits<Dest>::Shape,DenseShape>::value,int*>::type(0) )
+  {
+    addTo(dst, -lhs, rhs);
+  }
+
+protected:
+
+  // sparse = sparse * sparse
+  template<typename Dest>
+  static void evalTo(Dest& dst, const Lhs& lhs, const Rhs& rhs, SparseShape)
   {
     typedef typename nested_eval<Lhs,Dynamic>::type LhsNested;
     typedef typename nested_eval<Rhs,Dynamic>::type RhsNested;
@@ -47,6 +75,14 @@ struct generic_product_impl<Lhs, Rhs, SparseShape, SparseShape, ProductType>
     internal::conservative_sparse_sparse_product_selector<typename remove_all<LhsNested>::type,
                                                           typename remove_all<RhsNested>::type, Dest>::run(lhsNested,rhsNested,dst);
   }
+
+  // dense = sparse * sparse
+  template<typename Dest>
+  static void evalTo(Dest& dst, const Lhs& lhs, const Rhs& rhs, DenseShape)
+  {
+    dst.setZero();
+    addTo(dst, lhs, rhs);
+  }
 };
 
 // sparse * sparse-triangular
@@ -61,33 +97,36 @@ struct generic_product_impl<Lhs, Rhs, SparseTriangularShape, SparseShape, Produc
  : public generic_product_impl<Lhs, Rhs, SparseShape, SparseShape, ProductType>
 {};
 
-// Dense = sparse * sparse
-template< typename DstXprType, typename Lhs, typename Rhs, int Options/*, typename Scalar*/>
-struct Assignment<DstXprType, Product<Lhs,Rhs,Options>, internal::assign_op<typename DstXprType::Scalar>, Sparse2Dense/*,
-  typename enable_if<(Options==DefaultProduct || Options==AliasFreeProduct),Scalar>::type*/>
+// dense = sparse-product (can be sparse*sparse, sparse*perm, etc.)
+template< typename DstXprType, typename Lhs, typename Rhs>
+struct Assignment<DstXprType, Product<Lhs,Rhs,AliasFreeProduct>, internal::assign_op<typename DstXprType::Scalar>, Sparse2Dense>
 {
-  typedef Product<Lhs,Rhs,Options> SrcXprType;
+  typedef Product<Lhs,Rhs,AliasFreeProduct> SrcXprType;
   static void run(DstXprType &dst, const SrcXprType &src, const internal::assign_op<typename DstXprType::Scalar> &)
   {
-    dst.setZero();
-    dst += src;
+    generic_product_impl<Lhs, Rhs>::evalTo(dst,src.lhs(),src.rhs());
   }
 };
 
-// Dense += sparse * sparse
-template< typename DstXprType, typename Lhs, typename Rhs, int Options>
-struct Assignment<DstXprType, Product<Lhs,Rhs,Options>, internal::add_assign_op<typename DstXprType::Scalar>, Sparse2Dense/*,
-  typename enable_if<(Options==DefaultProduct || Options==AliasFreeProduct),Scalar>::type*/>
+// dense += sparse-product (can be sparse*sparse, sparse*perm, etc.)
+template< typename DstXprType, typename Lhs, typename Rhs>
+struct Assignment<DstXprType, Product<Lhs,Rhs,AliasFreeProduct>, internal::add_assign_op<typename DstXprType::Scalar>, Sparse2Dense>
 {
-  typedef Product<Lhs,Rhs,Options> SrcXprType;
+  typedef Product<Lhs,Rhs,AliasFreeProduct> SrcXprType;
   static void run(DstXprType &dst, const SrcXprType &src, const internal::add_assign_op<typename DstXprType::Scalar> &)
   {
-    typedef typename nested_eval<Lhs,Dynamic>::type LhsNested;
-    typedef typename nested_eval<Rhs,Dynamic>::type RhsNested;
-    LhsNested lhsNested(src.lhs());
-    RhsNested rhsNested(src.rhs());
-    internal::sparse_sparse_to_dense_product_selector<typename remove_all<LhsNested>::type,
-                                                      typename remove_all<RhsNested>::type, DstXprType>::run(lhsNested,rhsNested,dst);
+    generic_product_impl<Lhs, Rhs>::addTo(dst,src.lhs(),src.rhs());
+  }
+};
+
+// dense -= sparse-product (can be sparse*sparse, sparse*perm, etc.)
+template< typename DstXprType, typename Lhs, typename Rhs>
+struct Assignment<DstXprType, Product<Lhs,Rhs,AliasFreeProduct>, internal::sub_assign_op<typename DstXprType::Scalar>, Sparse2Dense>
+{
+  typedef Product<Lhs,Rhs,AliasFreeProduct> SrcXprType;
+  static void run(DstXprType &dst, const SrcXprType &src, const internal::sub_assign_op<typename DstXprType::Scalar> &)
+  {
+    generic_product_impl<Lhs, Rhs>::subTo(dst,src.lhs(),src.rhs());
   }
 };
 
diff --git a/test/sparse_basic.cpp b/test/sparse_basic.cpp
index e8ebd7000..d8e42e984 100644
--- a/test/sparse_basic.cpp
+++ b/test/sparse_basic.cpp
@@ -438,7 +438,7 @@ template<typename SparseMatrixType> void sparse_basic(const SparseMatrixType& re
     {
       Index i = internal::random<Index>(0,rows-1);
       Index j = internal::random<Index>(0,rows-1);
-      Index v = internal::random<Scalar>();
+      Scalar v = internal::random<Scalar>();
       m1.coeffRef(i,j) = v;
       refMat1.coeffRef(i,j) = v;
       VERIFY_IS_APPROX(m1, refMat1);
diff --git a/test/sparse_product.cpp b/test/sparse_product.cpp
index 8c83f08d7..7ec5270e8 100644
--- a/test/sparse_product.cpp
+++ b/test/sparse_product.cpp
@@ -79,12 +79,16 @@ template<typename SparseMatrixType> void sparse_product()
     // dense ?= sparse * sparse
     VERIFY_IS_APPROX(dm4 =m2*m3, refMat4 =refMat2*refMat3);
     VERIFY_IS_APPROX(dm4+=m2*m3, refMat4+=refMat2*refMat3);
+    VERIFY_IS_APPROX(dm4-=m2*m3, refMat4-=refMat2*refMat3);
     VERIFY_IS_APPROX(dm4 =m2t.transpose()*m3, refMat4 =refMat2t.transpose()*refMat3);
     VERIFY_IS_APPROX(dm4+=m2t.transpose()*m3, refMat4+=refMat2t.transpose()*refMat3);
+    VERIFY_IS_APPROX(dm4-=m2t.transpose()*m3, refMat4-=refMat2t.transpose()*refMat3);
     VERIFY_IS_APPROX(dm4 =m2t.transpose()*m3t.transpose(), refMat4 =refMat2t.transpose()*refMat3t.transpose());
     VERIFY_IS_APPROX(dm4+=m2t.transpose()*m3t.transpose(), refMat4+=refMat2t.transpose()*refMat3t.transpose());
+    VERIFY_IS_APPROX(dm4-=m2t.transpose()*m3t.transpose(), refMat4-=refMat2t.transpose()*refMat3t.transpose());
     VERIFY_IS_APPROX(dm4 =m2*m3t.transpose(), refMat4 =refMat2*refMat3t.transpose());
     VERIFY_IS_APPROX(dm4+=m2*m3t.transpose(), refMat4+=refMat2*refMat3t.transpose());
+    VERIFY_IS_APPROX(dm4-=m2*m3t.transpose(), refMat4-=refMat2*refMat3t.transpose());
     VERIFY_IS_APPROX(dm4 = m2*m3*s1, refMat4 = refMat2*refMat3*s1);
 
     // test aliasing