Add empty ctor for ViewBroadcast

Author: bartgol

src/kokkos/ekat_view_broadcast.hpp

@@ -22,15 +22,24 @@ class ViewBroadcast
   using view_type  = Unmanaged<ToView>;
   using reference_type = typename view_type::reference_type;
 
+  ViewBroadcast () = default;
+
+  template<typename FromView>
+  ViewBroadcast (const FromView& from_v,
+                 const std::vector<int>& extents)
+  {
+    setup(from_v,extents);
+  }
+
   // Broadcast an input view to the type provided by the class template arg
   //  - from_v: view to be broadcasted
   //  - extents: list of extents of the outfacing view (of type ToView).
   //    Must have rank=ToView::rank(). Must contain FromView::rank() entries
   //    that are <=0, which signal that those dimensions' extents will be
   //    retrieved from the input view.
   template<typename FromView>
-  ViewBroadcast (const FromView& from_v,
-                 const std::vector<int>& extents)
+  void setup (const FromView& from_v,
+              const std::vector<int>& extents)
   {
     constexpr int from_rank = FromView::rank();
     constexpr int to_rank = ToView::rank();

tests/kokkos/view_broadcast.cpp

@@ -45,7 +45,8 @@ TEST_CASE("view_broadcast") {
       SECTION ("along d0") {
         d0 = 4;
         d1 = n;
-        auto b2d = broadcast<view_2d>(orig,{d0,-1});
+        ViewBroadcast<view_2d> b2d;
+        b2d.setup(orig,{d0,-1});
 
         int err = 0;
         auto lambda = KOKKOS_LAMBDA (int idx, int& l_err) {