From 250e9fcc299cfba38bdc156a9ba102c00a0b6242 Mon Sep 17 00:00:00 2001
From: Tapish <narwal83@hzdr.de>
Date: Tue, 4 Feb 2025 15:28:04 +0100
Subject: [PATCH] Fix forwarding of custom tuple and add indexed apply

---
 include/picongpu/plugins/binning/Binner.hpp   |  4 +-
 .../plugins/binning/BinningFunctors.hpp       | 16 ++++----
 include/picongpu/plugins/binning/utility.hpp  | 41 +++++++++++++------
 include/pmacc/memory/STLTuple.hpp             | 11 +++++
 4 files changed, 51 insertions(+), 21 deletions(-)

diff --git a/include/picongpu/plugins/binning/Binner.hpp b/include/picongpu/plugins/binning/Binner.hpp
index 2e43a1e675..51a61651e4 100644
--- a/include/picongpu/plugins/binning/Binner.hpp
+++ b/include/picongpu/plugins/binning/Binner.hpp
@@ -115,7 +115,7 @@ namespace picongpu
                         {
                             pmacc::DataSpace<nAxes> const nDIdx = pmacc::math::mapToND(extentsDataspace, linearTid);
                             float_X factor = 1.;
-                            apply(
+                            binning::apply(
                                 [&](auto const&... binWidthsKernel)
                                 {
                                     // uses bin width for axes without dimensions as well should those be ignored?
@@ -246,7 +246,7 @@ namespace picongpu
                                 this->histBuffer->getDeviceBuffer().getDataBox());
 
                         // change output dimensions
-                        apply(
+                        std::apply(
                             [&](auto const&... tupleArgs)
                             { ((dimensionSubtraction(outputUnits, tupleArgs.units)), ...); },
                             binningData.axisTuple);
diff --git a/include/picongpu/plugins/binning/BinningFunctors.hpp b/include/picongpu/plugins/binning/BinningFunctors.hpp
index ebb057b0af..209192bf6d 100644
--- a/include/picongpu/plugins/binning/BinningFunctors.hpp
+++ b/include/picongpu/plugins/binning/BinningFunctors.hpp
@@ -53,19 +53,21 @@ namespace picongpu
 
                 auto binsDataspace = pmacc::DataSpace<T_nAxes>{};
                 bool validIdx = true;
-                apply(
-                    [&](auto const&... tupleArgs)
+                binning::applyIndexed(
+                    [&](auto const& tuple, auto... idxs)
                     {
-                        uint32_t i = 0;
                         // This assumes n_bins and getBinIdx exist
                         validIdx
-                            = ((
+                            = (
                                    [&]
                                    {
-                                       auto [isValid, binIdx] = tupleArgs.getBinIdx(domainInfo, worker, particle);
-                                       binsDataspace[i++] = binIdx;
+                                       auto [isValid, binIdx] = pmacc::memory::tuple::get<idxs>(tuple).getBinIdx(
+                                           domainInfo,
+                                           worker,
+                                           particle);
+                                       binsDataspace[idxs] = binIdx;
                                        return isValid;
-                                   }())
+                                   }()
                                && ...);
                     },
                     axes);
diff --git a/include/picongpu/plugins/binning/utility.hpp b/include/picongpu/plugins/binning/utility.hpp
index a6ae9ae2ac..c7ef59eabf 100644
--- a/include/picongpu/plugins/binning/utility.hpp
+++ b/include/picongpu/plugins/binning/utility.hpp
@@ -31,26 +31,43 @@ namespace picongpu
     {
         namespace detail
         {
-            template<typename TFunc, typename... TArgs, std::size_t... Is>
-            HDINLINE constexpr auto apply_impl(
-                TFunc&& f,
-                pmacc::memory::tuple::Tuple<TArgs...>&& t,
-                std::index_sequence<Is...>)
+            template<typename TFunc, typename TPmaccTuple, std::size_t... Is>
+            HDINLINE constexpr decltype(auto) applyImpl(TFunc&& f, TPmaccTuple&& t, std::index_sequence<Is...>)
             {
-                // @todo give Is as a param to f, so compiler has knowledge
-                return f(pmacc::memory::tuple::get<Is>(std::forward<pmacc::memory::tuple::Tuple<TArgs...>&&>(t))...);
+                return std::forward<TFunc>(f)(pmacc::memory::tuple::get<Is>(std::forward<TPmaccTuple>(t))...);
             }
+
+            template<typename TFunc, typename TPmaccTuple, std::size_t... Is>
+            HDINLINE constexpr decltype(auto) applyIdxImpl(TFunc&& f, TPmaccTuple&& t, std::index_sequence<Is...>)
+            {
+                return std::forward<TFunc>(
+                    f)(std::forward<TPmaccTuple>(t), std::integral_constant<std::size_t, Is>{}...);
+            }
+
+
         } // namespace detail
 
-        template<typename TFunc, typename... TArgs>
-        HDINLINE constexpr auto apply(TFunc&& f, pmacc::memory::tuple::Tuple<TArgs...> t)
+        // takes pmacc::memory::tuple::Tuple
+        template<typename TFunc, typename TPmaccTuple>
+        HDINLINE constexpr decltype(auto) apply(TFunc&& f, TPmaccTuple&& t)
         {
-            return detail::apply_impl(
+            return detail::applyImpl(
                 std::forward<TFunc>(f),
-                std::forward<pmacc::memory::tuple::Tuple<TArgs...>&&>(t),
-                std::make_index_sequence<sizeof...(TArgs)>{});
+                std::forward<TPmaccTuple>(t),
+                std::make_index_sequence<pmacc::memory::tuple::tuple_size_v<TPmaccTuple>>{});
         }
 
+        // takes pmacc::memory::tuple::Tuple
+        template<typename TFunc, typename TPmaccTuple>
+        HDINLINE constexpr decltype(auto) applyIndexed(TFunc&& f, TPmaccTuple&& t)
+        {
+            return detail::applyIdxImpl(
+                std::forward<TFunc>(f),
+                std::forward<TPmaccTuple>(t),
+                std::make_index_sequence<pmacc::memory::tuple::tuple_size_v<TPmaccTuple>>{});
+        }
+
+
         namespace detail
         {
             template<size_t... Is, typename... Args, typename Functor>
diff --git a/include/pmacc/memory/STLTuple.hpp b/include/pmacc/memory/STLTuple.hpp
index 95edcac546..677c9266cc 100644
--- a/include/pmacc/memory/STLTuple.hpp
+++ b/include/pmacc/memory/STLTuple.hpp
@@ -193,6 +193,17 @@ static constexpr size_t size(Tuple<Args...>&) {
   return sizeof...(Args);
 }
 
+ // Handles cv-qualifiers and refs
+template <typename T>
+struct tuple_size : tuple_size<std::remove_cvref_t<T>> {};
+
+template <typename... Args>
+struct tuple_size<Tuple<Args...>> : std::integral_constant<std::size_t, sizeof...(Args)>{
+};
+
+template<typename T>
+constexpr std::size_t tuple_size_v = tuple_size<T>::value;
+
 /// @struct IndexList
 /// @brief Creates a list of index from the elements in the tuple
 /// @tparam Is... a list of index from [0 to sizeof...(tuple elements))