Create contiguous helper field

components/eamxx/src/share/field/field.cpp

@@ -137,6 +137,14 @@ subfield (const std::string& sf_name, const ekat::units::Units& sf_units,
   sf.m_data = m_data;
   sf.m_is_read_only = m_is_read_only;
 
+  if (not sf.m_header->get_alloc_properties().contiguous() and
+      not sf.host_and_device_share_memory_space()) {
+    // If subfield is not contiguous and Host and Device do not
+    // share a memory space, we must initialize the helper field
+    // for sync_to functions.
+    sf.initialize_contiguous_helper_field();
+  }
+
   return sf;
 }
 
@@ -178,6 +186,14 @@ Field Field::subfield(const std::string& sf_name,
                                        index_end);
   sf.m_data = m_data;
 
+  if (not sf.m_header->get_alloc_properties().contiguous() and
+      not sf.host_and_device_share_memory_space()) {
+    // If subfield is not contiguous and Host and Device do not
+    // share a memory space, we must initialize the helper field
+    // for sync_to functions.
+    sf.initialize_contiguous_helper_field();
+  }
+
   return sf;
 }
 

components/eamxx/src/share/field/field.hpp

@@ -278,6 +278,27 @@ class Field {
   // Allocate the actual view
   void allocate_view ();
 
+  // Create contiguous helper field for running sync_to_host
+  // and sync_to_device with non-contiguous fields
+  void initialize_contiguous_helper_field () {
+    EKAT_REQUIRE_MSG(not m_header->get_alloc_properties().contiguous(),
+                     "Error! We should not setup contiguous helper field "
+                     "for an already contiguous field.\n");
+    EKAT_REQUIRE_MSG(not host_and_device_share_memory_space(),
+                     "Error! We should not setup contiguous helper field for a field "
+                     "when host and device share a memory space.\n");
+
+    auto id = m_header->get_identifier();
+    Field contig(id.alias(name()+std::string("_contiguous")));
+    contig.allocate_view();
+
+    // Sanity check
+    EKAT_REQUIRE_MSG(contig.get_header().get_alloc_properties().contiguous(),
+                     "Error! Contiguous helper field must be contiguous.\n");
+
+    m_contiguous_field = std::make_shared<Field>(contig);
+  }
+
   inline bool host_and_device_share_memory_space() const {
     EKAT_REQUIRE_MSG(is_allocated(),
                      "Error! Must allocate view before querying "
@@ -347,6 +368,10 @@ class Field {
   // Actual data.
   dual_view_t<char*> m_data;
 
+  // Field needed for sync host/device in case of non-contiguous
+  // field when host and device do not share a memory space.
+  std::shared_ptr<Field> m_contiguous_field;
+
   // Whether this field is read-only. This is given
   // mutable keyword since it needs to be turned off/on
   // to allow sync_to_host for constant, read-only fields.