Merge pull request #264 from JM1/master

Fix ambiguous template special. errors with GCC 7+

Author: poulson

include/El/blas_like/level1/decl.hpp

@@ -487,7 +487,7 @@ void Contract( const BlockMatrix<T>& A, BlockMatrix<T>& B );
 template<typename T>
 void Copy( const Matrix<T>& A, Matrix<T>& B );
 template<typename S,typename T,
-         typename=EnableIf<CanCast<S,T>>>
+         typename=EnableIf<And< CanCast<S,T>, Not<IsSame<S,T>> >>>
 void Copy( const Matrix<S>& A, Matrix<T>& B );
 
 template<typename S,typename T,
@@ -501,7 +501,7 @@ void Copy( const BlockMatrix<S>& A, BlockMatrix<T>& B );
 template<typename T>
 void Copy( const AbstractDistMatrix<T>& A, AbstractDistMatrix<T>& B );
 template<typename S,typename T,
-         typename=EnableIf<CanCast<S,T>>>
+         typename=EnableIf<And< CanCast<S,T>, Not<IsSame<S,T>> >>>
 void Copy( const AbstractDistMatrix<S>& A, AbstractDistMatrix<T>& B );
 
 template<typename T>
@@ -532,7 +532,7 @@ template<typename T>
 void Copy( const SparseMatrix<T>& A, SparseMatrix<T>& B );
 
 template<typename S,typename T,
-         typename=EnableIf<CanCast<S,T>>>
+         typename=EnableIf<And< CanCast<S,T>, Not<IsSame<S,T>> >> >
 void Copy( const SparseMatrix<S>& A, SparseMatrix<T>& B );
 
 template<typename S,typename T,
@@ -543,7 +543,7 @@ template<typename T>
 void Copy( const DistSparseMatrix<T>& A, DistSparseMatrix<T>& B );
 
 template<typename S,typename T,
-         typename=EnableIf<CanCast<S,T>>>
+         typename=EnableIf<And<CanCast<S,T>,Not<IsSame<S,T>>>>>
 void Copy( const DistSparseMatrix<S>& A, DistSparseMatrix<T>& B );
 
 template<typename S,typename T,
@@ -559,7 +559,7 @@ template<typename T>
 void Copy( const DistMultiVec<T>& A, DistMultiVec<T>& B );
 
 template<typename S,typename T,
-         typename=EnableIf<CanCast<S,T>>>
+         typename=EnableIf< And< CanCast<S,T>, Not<IsSame<S,T>> > >>
 void Copy( const DistMultiVec<S>& A, DistMultiVec<T>& B );
 
 template<typename T>

include/El/core.hpp

@@ -102,6 +102,16 @@ enum FortranLogicalEnum
 template<typename S,typename T>
 using IsSame = std::is_same<S,T>;
 
+template<typename S, typename T>
+struct And {
+	static constexpr bool value = S::value && T::value;
+};
+
+template<typename T>
+struct Not {
+	static constexpr bool value = !T::value;
+};
+
 template<typename Condition,class T=void>
 using EnableIf = typename std::enable_if<Condition::value,T>::type;
 template<typename Condition,class T=void>