Added sequential device to atomic operations.

src/TNL/Algorithms/AtomicOperations.h

@@ -41,6 +41,21 @@ struct AtomicOperations< Devices::Host >
    }
 };
 
+template<>
+struct AtomicOperations< Devices::Sequential >
+{
+   // this is __cuda_callable__ only to silence nvcc warnings (all methods inside class
+   // template specializations must have the same execution space specifier, otherwise
+   // nvcc complains)
+   TNL_NVCC_HD_WARNING_DISABLE
+   template< typename Value >
+   __cuda_callable__
+   static void add( Value& v, const Value& a )
+   {
+      v += a;
+   }
+};
+
 template<>
 struct AtomicOperations< Devices::Cuda >
 {

src/TNL/Atomic.h

@@ -15,6 +15,7 @@
 #include <atomic>  // std::atomic
 
 #include <TNL/Devices/Host.h>
+#include <TNL/Devices/Sequential.h>
 #include <TNL/Devices/Cuda.h>
 
 // double-precision atomicAdd function for Maxwell and older GPUs
@@ -96,6 +97,17 @@ public:
    }
 };
 
+template< typename T >
+class Atomic< T, Devices::Sequential > : public Atomic< T, Devices::Host >
+{
+   public:
+
+   using Atomic;
+   using operator=;
+   using fetch_max;
+   using fetch_min;
+};
+
 template< typename T >
 class Atomic< T, Devices::Cuda >
 {