From c607f8ad4a64b6bf09ea42cf07510370a5573ad8 Mon Sep 17 00:00:00 2001
From: Matti Kortelainen <matti.kortelainen@cern.ch>
Date: Thu, 9 Nov 2023 17:11:13 +0100
Subject: [PATCH 1/2] Allow Portable{Collection,Object}<T, TDev> to be used
 also independently of ALPAKA_ACCELERATOR_NAMESPACE

---
 .../Portable/interface/PortableCollection.h   |  4 ++-
 .../interface/PortableHostCollection.h        | 10 ++++++++
 .../Portable/interface/PortableHostObject.h   | 10 ++++++++
 .../Portable/interface/PortableObject.h       |  4 +--
 .../interface/alpaka/PortableCollection.h     |  5 +++-
 .../interface/alpaka/PortableObject.h         |  5 +++-
 DataFormats/Portable/test/BuildFile.xml       |  5 ++++
 .../Portable/test/portableCollectionOnHost.cc | 25 +++++++++++++++++++
 .../Portable/test/portableObjectOnHost.cc     | 23 +++++++++++++++++
 DataFormats/Portable/test/test_catch2_main.cc |  2 ++
 10 files changed, 88 insertions(+), 5 deletions(-)
 create mode 100644 DataFormats/Portable/test/BuildFile.xml
 create mode 100644 DataFormats/Portable/test/portableCollectionOnHost.cc
 create mode 100644 DataFormats/Portable/test/portableObjectOnHost.cc
 create mode 100644 DataFormats/Portable/test/test_catch2_main.cc

diff --git a/DataFormats/Portable/interface/PortableCollection.h b/DataFormats/Portable/interface/PortableCollection.h
index 86d117c02c81d..9a0498944688d 100644
--- a/DataFormats/Portable/interface/PortableCollection.h
+++ b/DataFormats/Portable/interface/PortableCollection.h
@@ -1,13 +1,15 @@
 #ifndef DataFormats_Portable_interface_PortableCollection_h
 #define DataFormats_Portable_interface_PortableCollection_h
 
+#include <alpaka/alpaka.hpp>
+
 #include "HeterogeneousCore/AlpakaInterface/interface/traits.h"
 
 namespace traits {
 
   // trait for a generic SoA-based product
   template <typename T, typename TDev, typename = std::enable_if_t<alpaka::isDevice<TDev>>>
-  class PortableCollectionTrait;
+  struct PortableCollectionTrait;
 
 }  // namespace traits
 
diff --git a/DataFormats/Portable/interface/PortableHostCollection.h b/DataFormats/Portable/interface/PortableHostCollection.h
index 8b098688455e8..e73e70e724bb6 100644
--- a/DataFormats/Portable/interface/PortableHostCollection.h
+++ b/DataFormats/Portable/interface/PortableHostCollection.h
@@ -6,6 +6,7 @@
 
 #include <alpaka/alpaka.hpp>
 
+#include "DataFormats/Portable/interface/PortableCollection.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/config.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/host.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/memory.h"
@@ -86,4 +87,13 @@ class PortableHostCollection {
   View view_;                     //!
 };
 
+// Make PortableCollection<T, TDev> alias template to work also
+// independently of ALPAKA_ACCELERATOR_NAMESPACE
+namespace traits {
+  template <typename T>
+  struct PortableCollectionTrait<T, alpaka::DevCpu> {
+    using CollectionType = PortableHostCollection<T>;
+  };
+}  // namespace traits
+
 #endif  // DataFormats_Portable_interface_PortableHostCollection_h
diff --git a/DataFormats/Portable/interface/PortableHostObject.h b/DataFormats/Portable/interface/PortableHostObject.h
index 348da4f8c505d..c0f476d2f2d2a 100644
--- a/DataFormats/Portable/interface/PortableHostObject.h
+++ b/DataFormats/Portable/interface/PortableHostObject.h
@@ -7,6 +7,7 @@
 
 #include <alpaka/alpaka.hpp>
 
+#include "DataFormats/Portable/interface/PortableObject.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/config.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/host.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/memory.h"
@@ -78,4 +79,13 @@ class PortableHostObject {
   Product* product_;
 };
 
+// Make PortableObject<T, TDev> alias template to work also
+// independently of ALPAKA_ACCELERATOR_NAMESPACE
+namespace traits {
+  template <typename T>
+  struct PortableObjectTrait<T, alpaka::DevCpu> {
+    using ProductType = PortableHostObject<T>;
+  };
+}  // namespace traits
+
 #endif  // DataFormats_Portable_interface_PortableHostObject_h
diff --git a/DataFormats/Portable/interface/PortableObject.h b/DataFormats/Portable/interface/PortableObject.h
index 90a33b49d0f0a..a4737e67e7dd7 100644
--- a/DataFormats/Portable/interface/PortableObject.h
+++ b/DataFormats/Portable/interface/PortableObject.h
@@ -3,13 +3,13 @@
 
 #include <type_traits>
 
-#include "HeterogeneousCore/AlpakaInterface/interface/traits.h"
+#include <alpaka/alpaka.hpp>
 
 namespace traits {
 
   // trait for a generic SoA-based product
   template <typename T, typename TDev, typename = std::enable_if_t<alpaka::isDevice<TDev>>>
-  class PortableObjectTrait;
+  struct PortableObjectTrait;
 
 }  // namespace traits
 
diff --git a/DataFormats/Portable/interface/alpaka/PortableCollection.h b/DataFormats/Portable/interface/alpaka/PortableCollection.h
index 0a6abad96dfaf..232f0eefdd038 100644
--- a/DataFormats/Portable/interface/alpaka/PortableCollection.h
+++ b/DataFormats/Portable/interface/alpaka/PortableCollection.h
@@ -33,15 +33,18 @@ namespace ALPAKA_ACCELERATOR_NAMESPACE {
 
 }  // namespace ALPAKA_ACCELERATOR_NAMESPACE
 
+// For DevHost the specialisation is already done in the PortableHostCollection.h
+#ifndef ALPAKA_ACC_CPU_B_SEQ_T_SEQ_ENABLED
 namespace traits {
 
   // specialise the trait for the device provided by the ALPAKA_ACCELERATOR_NAMESPACE
   template <typename T>
-  class PortableCollectionTrait<T, ALPAKA_ACCELERATOR_NAMESPACE::Device> {
+  struct PortableCollectionTrait<T, ALPAKA_ACCELERATOR_NAMESPACE::Device> {
     using CollectionType = ALPAKA_ACCELERATOR_NAMESPACE::PortableCollection<T>;
   };
 
 }  // namespace traits
+#endif
 
 namespace cms::alpakatools {
   template <typename TLayout, typename TDevice>
diff --git a/DataFormats/Portable/interface/alpaka/PortableObject.h b/DataFormats/Portable/interface/alpaka/PortableObject.h
index 9b7ba65f8a460..f58c487be7dd9 100644
--- a/DataFormats/Portable/interface/alpaka/PortableObject.h
+++ b/DataFormats/Portable/interface/alpaka/PortableObject.h
@@ -33,15 +33,18 @@ namespace ALPAKA_ACCELERATOR_NAMESPACE {
 
 }  // namespace ALPAKA_ACCELERATOR_NAMESPACE
 
+// For DevHost the specialisation is already done in the PortableHostCollection.h
+#ifndef ALPAKA_ACC_CPU_B_SEQ_T_SEQ_ENABLED
 namespace traits {
 
   // specialise the trait for the device provided by the ALPAKA_ACCELERATOR_NAMESPACE
   template <typename T>
-  class PortableObjectTrait<T, ALPAKA_ACCELERATOR_NAMESPACE::Device> {
+  struct PortableObjectTrait<T, ALPAKA_ACCELERATOR_NAMESPACE::Device> {
     using ProductType = ALPAKA_ACCELERATOR_NAMESPACE::PortableObject<T>;
   };
 
 }  // namespace traits
+#endif
 
 namespace cms::alpakatools {
   template <typename TProduct, typename TDevice>
diff --git a/DataFormats/Portable/test/BuildFile.xml b/DataFormats/Portable/test/BuildFile.xml
new file mode 100644
index 0000000000000..ef2f6603f62cc
--- /dev/null
+++ b/DataFormats/Portable/test/BuildFile.xml
@@ -0,0 +1,5 @@
+<bin name="TestDataFormatsPortableOnHost" file="test_catch2_main.cc,portableCollectionOnHost.cc,portableObjectOnHost.cc">
+  <use name="DataFormats/Portable"/>
+  <use name="DataFormats/SoATemplate"/>
+  <use name="catch2"/>
+</bin>
diff --git a/DataFormats/Portable/test/portableCollectionOnHost.cc b/DataFormats/Portable/test/portableCollectionOnHost.cc
new file mode 100644
index 0000000000000..aa3d56f9d0539
--- /dev/null
+++ b/DataFormats/Portable/test/portableCollectionOnHost.cc
@@ -0,0 +1,25 @@
+#include <catch.hpp>
+
+#include "DataFormats/Portable/interface/PortableCollection.h"
+#include "DataFormats/Portable/interface/PortableHostCollection.h"
+#include "DataFormats/SoATemplate/interface/SoACommon.h"
+#include "DataFormats/SoATemplate/interface/SoALayout.h"
+#include "DataFormats/SoATemplate/interface/SoAView.h"
+
+namespace {
+  GENERATE_SOA_LAYOUT(TestLayout, SOA_COLUMN(double, x), SOA_COLUMN(int32_t, id))
+
+  using TestSoA = TestLayout<>;
+
+  constexpr auto s_tag = "[PortableCollection]";
+}  // namespace
+
+// This test is currently mostly about the code compiling
+TEST_CASE("Use of PortableCollection<T, TDev> on host code", s_tag) {
+  auto const size = 10;
+  PortableCollection<TestSoA, alpaka::DevCpu> coll(size, cms::alpakatools::host());
+
+  SECTION("Tests") { REQUIRE(coll->metadata().size() == size); }
+
+  static_assert(std::is_same_v<PortableCollection<TestSoA, alpaka::DevCpu>, PortableHostCollection<TestSoA>>);
+}
diff --git a/DataFormats/Portable/test/portableObjectOnHost.cc b/DataFormats/Portable/test/portableObjectOnHost.cc
new file mode 100644
index 0000000000000..698605b57f465
--- /dev/null
+++ b/DataFormats/Portable/test/portableObjectOnHost.cc
@@ -0,0 +1,23 @@
+#include <catch.hpp>
+
+#include "DataFormats/Portable/interface/PortableObject.h"
+#include "DataFormats/Portable/interface/PortableHostObject.h"
+
+namespace {
+  struct Test {
+    int a;
+    float b;
+  };
+
+  constexpr auto s_tag = "[PortableObject]";
+}  // namespace
+
+// This test is currently mostly about the code compiling
+TEST_CASE("Use of PortableObject<T> on host code", s_tag) {
+  PortableObject<Test, alpaka::DevCpu> obj(cms::alpakatools::host());
+  obj->a = 42;
+
+  SECTION("Tests") { REQUIRE(obj->a == 42); }
+
+  static_assert(std::is_same_v<PortableObject<Test, alpaka::DevCpu>, PortableHostObject<Test>>);
+}
diff --git a/DataFormats/Portable/test/test_catch2_main.cc b/DataFormats/Portable/test/test_catch2_main.cc
new file mode 100644
index 0000000000000..b3143fbb1788b
--- /dev/null
+++ b/DataFormats/Portable/test/test_catch2_main.cc
@@ -0,0 +1,2 @@
+#define CATCH_CONFIG_MAIN
+#include <catch.hpp>

From 1143991b0e5c92f27219d93f011059b7dc947ce6 Mon Sep 17 00:00:00 2001
From: Matti Kortelainen <matti.kortelainen@cern.ch>
Date: Wed, 8 Nov 2023 18:57:12 +0100
Subject: [PATCH 2/2] Simplify the definition of Portable{Collection,Object}<T,
 TDev> alias templates

Also move the CopyTo{Host,Device} specialisations to interface/ as
they are independent from ALPAKA_ACCELERATOR_NAMESPACE.
---
 .../Portable/interface/PortableCollection.h   | 39 ++++++++++++-
 .../interface/PortableHostCollection.h        | 10 ----
 .../Portable/interface/PortableHostObject.h   | 10 ----
 .../Portable/interface/PortableObject.h       | 43 ++++++++++++++-
 .../interface/alpaka/PortableCollection.h     | 55 +------------------
 .../interface/alpaka/PortableObject.h         | 55 +------------------
 6 files changed, 81 insertions(+), 131 deletions(-)

diff --git a/DataFormats/Portable/interface/PortableCollection.h b/DataFormats/Portable/interface/PortableCollection.h
index 9a0498944688d..abc64b99cb0d3 100644
--- a/DataFormats/Portable/interface/PortableCollection.h
+++ b/DataFormats/Portable/interface/PortableCollection.h
@@ -3,13 +3,24 @@
 
 #include <alpaka/alpaka.hpp>
 
-#include "HeterogeneousCore/AlpakaInterface/interface/traits.h"
+#include "DataFormats/Portable/interface/PortableHostCollection.h"
+#include "DataFormats/Portable/interface/PortableDeviceCollection.h"
+#include "HeterogeneousCore/AlpakaInterface/interface/CopyToDevice.h"
+#include "HeterogeneousCore/AlpakaInterface/interface/CopyToHost.h"
 
 namespace traits {
 
   // trait for a generic SoA-based product
   template <typename T, typename TDev, typename = std::enable_if_t<alpaka::isDevice<TDev>>>
-  struct PortableCollectionTrait;
+  struct PortableCollectionTrait {
+    using CollectionType = PortableDeviceCollection<T, TDev>;
+  };
+
+  // specialise for host device
+  template <typename T>
+  struct PortableCollectionTrait<T, alpaka_common::DevHost> {
+    using CollectionType = PortableHostCollection<T>;
+  };
 
 }  // namespace traits
 
@@ -17,4 +28,28 @@ namespace traits {
 template <typename T, typename TDev, typename = std::enable_if_t<alpaka::isDevice<TDev>>>
 using PortableCollection = typename traits::PortableCollectionTrait<T, TDev>::CollectionType;
 
+// define how to copy PortableCollection between host and device
+namespace cms::alpakatools {
+  template <typename TLayout, typename TDevice>
+  struct CopyToHost<PortableDeviceCollection<TLayout, TDevice>> {
+    template <typename TQueue>
+    static auto copyAsync(TQueue& queue, PortableDeviceCollection<TLayout, TDevice> const& srcData) {
+      PortableHostCollection<TLayout> dstData(srcData->metadata().size(), queue);
+      alpaka::memcpy(queue, dstData.buffer(), srcData.buffer());
+      return dstData;
+    }
+  };
+
+  template <typename TLayout>
+  struct CopyToDevice<PortableHostCollection<TLayout>> {
+    template <typename TQueue>
+    static auto copyAsync(TQueue& queue, PortableHostCollection<TLayout> const& srcData) {
+      using TDevice = typename alpaka::trait::DevType<TQueue>::type;
+      PortableDeviceCollection<TLayout, TDevice> dstData(srcData->metadata().size(), queue);
+      alpaka::memcpy(queue, dstData.buffer(), srcData.buffer());
+      return dstData;
+    }
+  };
+}  // namespace cms::alpakatools
+
 #endif  // DataFormats_Portable_interface_PortableCollection_h
diff --git a/DataFormats/Portable/interface/PortableHostCollection.h b/DataFormats/Portable/interface/PortableHostCollection.h
index e73e70e724bb6..8b098688455e8 100644
--- a/DataFormats/Portable/interface/PortableHostCollection.h
+++ b/DataFormats/Portable/interface/PortableHostCollection.h
@@ -6,7 +6,6 @@
 
 #include <alpaka/alpaka.hpp>
 
-#include "DataFormats/Portable/interface/PortableCollection.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/config.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/host.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/memory.h"
@@ -87,13 +86,4 @@ class PortableHostCollection {
   View view_;                     //!
 };
 
-// Make PortableCollection<T, TDev> alias template to work also
-// independently of ALPAKA_ACCELERATOR_NAMESPACE
-namespace traits {
-  template <typename T>
-  struct PortableCollectionTrait<T, alpaka::DevCpu> {
-    using CollectionType = PortableHostCollection<T>;
-  };
-}  // namespace traits
-
 #endif  // DataFormats_Portable_interface_PortableHostCollection_h
diff --git a/DataFormats/Portable/interface/PortableHostObject.h b/DataFormats/Portable/interface/PortableHostObject.h
index c0f476d2f2d2a..348da4f8c505d 100644
--- a/DataFormats/Portable/interface/PortableHostObject.h
+++ b/DataFormats/Portable/interface/PortableHostObject.h
@@ -7,7 +7,6 @@
 
 #include <alpaka/alpaka.hpp>
 
-#include "DataFormats/Portable/interface/PortableObject.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/config.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/host.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/memory.h"
@@ -79,13 +78,4 @@ class PortableHostObject {
   Product* product_;
 };
 
-// Make PortableObject<T, TDev> alias template to work also
-// independently of ALPAKA_ACCELERATOR_NAMESPACE
-namespace traits {
-  template <typename T>
-  struct PortableObjectTrait<T, alpaka::DevCpu> {
-    using ProductType = PortableHostObject<T>;
-  };
-}  // namespace traits
-
 #endif  // DataFormats_Portable_interface_PortableHostObject_h
diff --git a/DataFormats/Portable/interface/PortableObject.h b/DataFormats/Portable/interface/PortableObject.h
index a4737e67e7dd7..c9aadb160bb05 100644
--- a/DataFormats/Portable/interface/PortableObject.h
+++ b/DataFormats/Portable/interface/PortableObject.h
@@ -5,16 +5,53 @@
 
 #include <alpaka/alpaka.hpp>
 
+#include "DataFormats/Portable/interface/PortableHostObject.h"
+#include "DataFormats/Portable/interface/PortableDeviceObject.h"
+#include "HeterogeneousCore/AlpakaInterface/interface/CopyToDevice.h"
+#include "HeterogeneousCore/AlpakaInterface/interface/CopyToHost.h"
+
 namespace traits {
 
-  // trait for a generic SoA-based product
+  // trait for a generic struct-based product
   template <typename T, typename TDev, typename = std::enable_if_t<alpaka::isDevice<TDev>>>
-  struct PortableObjectTrait;
+  struct PortableObjectTrait {
+    using ProductType = PortableDeviceObject<T, TDev>;
+  };
+
+  // specialise for host device
+  template <typename T>
+  struct PortableObjectTrait<T, alpaka_common::DevHost> {
+    using ProductType = PortableHostObject<T>;
+  };
 
 }  // namespace traits
 
-// type alias for a generic SoA-based product
+// type alias for a generic struct-based product
 template <typename T, typename TDev, typename = std::enable_if_t<alpaka::isDevice<TDev>>>
 using PortableObject = typename traits::PortableObjectTrait<T, TDev>::ProductType;
 
+// define how to copy PortableObject between host and device
+namespace cms::alpakatools {
+  template <typename TProduct, typename TDevice>
+  struct CopyToHost<PortableDeviceObject<TProduct, TDevice>> {
+    template <typename TQueue>
+    static auto copyAsync(TQueue& queue, PortableDeviceObject<TProduct, TDevice> const& srcData) {
+      PortableHostObject<TProduct> dstData(queue);
+      alpaka::memcpy(queue, dstData.buffer(), srcData.buffer());
+      return dstData;
+    }
+  };
+
+  template <typename TProduct>
+  struct CopyToDevice<PortableHostObject<TProduct>> {
+    template <typename TQueue>
+    static auto copyAsync(TQueue& queue, PortableHostObject<TProduct> const& srcData) {
+      using TDevice = typename alpaka::trait::DevType<TQueue>::type;
+      PortableDeviceObject<TProduct, TDevice> dstData(queue);
+      alpaka::memcpy(queue, dstData.buffer(), srcData.buffer());
+      return dstData;
+    }
+  };
+}  // namespace cms::alpakatools
+
 #endif  // DataFormats_Portable_interface_PortableObject_h
diff --git a/DataFormats/Portable/interface/alpaka/PortableCollection.h b/DataFormats/Portable/interface/alpaka/PortableCollection.h
index 232f0eefdd038..1f9fa22e49cd8 100644
--- a/DataFormats/Portable/interface/alpaka/PortableCollection.h
+++ b/DataFormats/Portable/interface/alpaka/PortableCollection.h
@@ -4,11 +4,7 @@
 #include <alpaka/alpaka.hpp>
 
 #include "DataFormats/Portable/interface/PortableCollection.h"
-#include "DataFormats/Portable/interface/PortableHostCollection.h"
-#include "DataFormats/Portable/interface/PortableDeviceCollection.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/config.h"
-#include "HeterogeneousCore/AlpakaInterface/interface/CopyToDevice.h"
-#include "HeterogeneousCore/AlpakaInterface/interface/CopyToHost.h"
 
 // This header is not used by PortableCollection, but is included here to automatically
 // provide its content to users of ALPAKA_ACCELERATOR_NAMESPACE::PortableCollection.
@@ -16,57 +12,10 @@
 
 namespace ALPAKA_ACCELERATOR_NAMESPACE {
 
-#if defined ALPAKA_ACC_CPU_B_SEQ_T_SEQ_ENABLED
-  // ... or any other CPU-based accelerators
-
-  // generic SoA-based product in host memory
-  template <typename T>
-  using PortableCollection = ::PortableHostCollection<T>;
-
-#else
-
-  // generic SoA-based product in device memory
+  // generic SoA-based product in the device (that may be host) memory
   template <typename T>
-  using PortableCollection = ::PortableDeviceCollection<T, Device>;
-
-#endif  // ALPAKA_ACC_CPU_B_SEQ_T_SEQ_ENABLED
+  using PortableCollection = ::PortableCollection<T, Device>;
 
 }  // namespace ALPAKA_ACCELERATOR_NAMESPACE
 
-// For DevHost the specialisation is already done in the PortableHostCollection.h
-#ifndef ALPAKA_ACC_CPU_B_SEQ_T_SEQ_ENABLED
-namespace traits {
-
-  // specialise the trait for the device provided by the ALPAKA_ACCELERATOR_NAMESPACE
-  template <typename T>
-  struct PortableCollectionTrait<T, ALPAKA_ACCELERATOR_NAMESPACE::Device> {
-    using CollectionType = ALPAKA_ACCELERATOR_NAMESPACE::PortableCollection<T>;
-  };
-
-}  // namespace traits
-#endif
-
-namespace cms::alpakatools {
-  template <typename TLayout, typename TDevice>
-  struct CopyToHost<PortableDeviceCollection<TLayout, TDevice>> {
-    template <typename TQueue>
-    static auto copyAsync(TQueue& queue, PortableDeviceCollection<TLayout, TDevice> const& srcData) {
-      PortableHostCollection<TLayout> dstData(srcData->metadata().size(), queue);
-      alpaka::memcpy(queue, dstData.buffer(), srcData.buffer());
-      return dstData;
-    }
-  };
-
-  template <typename TLayout>
-  struct CopyToDevice<PortableHostCollection<TLayout>> {
-    template <typename TQueue>
-    static auto copyAsync(TQueue& queue, PortableHostCollection<TLayout> const& srcData) {
-      using TDevice = typename alpaka::trait::DevType<TQueue>::type;
-      PortableDeviceCollection<TLayout, TDevice> dstData(srcData->metadata().size(), queue);
-      alpaka::memcpy(queue, dstData.buffer(), srcData.buffer());
-      return dstData;
-    }
-  };
-}  // namespace cms::alpakatools
-
 #endif  // DataFormats_Portable_interface_alpaka_PortableCollection_h
diff --git a/DataFormats/Portable/interface/alpaka/PortableObject.h b/DataFormats/Portable/interface/alpaka/PortableObject.h
index f58c487be7dd9..417173176b203 100644
--- a/DataFormats/Portable/interface/alpaka/PortableObject.h
+++ b/DataFormats/Portable/interface/alpaka/PortableObject.h
@@ -4,11 +4,7 @@
 #include <alpaka/alpaka.hpp>
 
 #include "DataFormats/Portable/interface/PortableObject.h"
-#include "DataFormats/Portable/interface/PortableHostObject.h"
-#include "DataFormats/Portable/interface/PortableDeviceObject.h"
 #include "HeterogeneousCore/AlpakaInterface/interface/config.h"
-#include "HeterogeneousCore/AlpakaInterface/interface/CopyToDevice.h"
-#include "HeterogeneousCore/AlpakaInterface/interface/CopyToHost.h"
 
 // This header is not used by PortableObject, but is included here to automatically
 // provide its content to users of ALPAKA_ACCELERATOR_NAMESPACE::PortableObject.
@@ -16,57 +12,10 @@
 
 namespace ALPAKA_ACCELERATOR_NAMESPACE {
 
-#if defined ALPAKA_ACC_CPU_B_SEQ_T_SEQ_ENABLED
-  // ... or any other CPU-based accelerators
-
-  // generic SoA-based product in host memory
-  template <typename T>
-  using PortableObject = ::PortableHostObject<T>;
-
-#else
-
-  // generic SoA-based product in device memory
+  // generic struct-based product in the device (that may be host) memory
   template <typename T>
-  using PortableObject = ::PortableDeviceObject<T, Device>;
-
-#endif  // ALPAKA_ACC_CPU_B_SEQ_T_SEQ_ENABLED
+  using PortableObject = ::PortableObject<T, Device>;
 
 }  // namespace ALPAKA_ACCELERATOR_NAMESPACE
 
-// For DevHost the specialisation is already done in the PortableHostCollection.h
-#ifndef ALPAKA_ACC_CPU_B_SEQ_T_SEQ_ENABLED
-namespace traits {
-
-  // specialise the trait for the device provided by the ALPAKA_ACCELERATOR_NAMESPACE
-  template <typename T>
-  struct PortableObjectTrait<T, ALPAKA_ACCELERATOR_NAMESPACE::Device> {
-    using ProductType = ALPAKA_ACCELERATOR_NAMESPACE::PortableObject<T>;
-  };
-
-}  // namespace traits
-#endif
-
-namespace cms::alpakatools {
-  template <typename TProduct, typename TDevice>
-  struct CopyToHost<PortableDeviceObject<TProduct, TDevice>> {
-    template <typename TQueue>
-    static auto copyAsync(TQueue& queue, PortableDeviceObject<TProduct, TDevice> const& srcData) {
-      PortableHostObject<TProduct> dstData(queue);
-      alpaka::memcpy(queue, dstData.buffer(), srcData.buffer());
-      return dstData;
-    }
-  };
-
-  template <typename TProduct>
-  struct CopyToDevice<PortableHostObject<TProduct>> {
-    template <typename TQueue>
-    static auto copyAsync(TQueue& queue, PortableHostObject<TProduct> const& srcData) {
-      using TDevice = typename alpaka::trait::DevType<TQueue>::type;
-      PortableDeviceObject<TProduct, TDevice> dstData(queue);
-      alpaka::memcpy(queue, dstData.buffer(), srcData.buffer());
-      return dstData;
-    }
-  };
-}  // namespace cms::alpakatools
-
 #endif  // DataFormats_Portable_interface_alpaka_PortableObject_h