Fix problem with particle_type in container

experimental/include/scalfmm/meta/traits.hpp

@@ -11,15 +11,9 @@
 #include <type_traits>
 
 #include <scalfmm/meta/is_valid.hpp>
+#include <scalfmm/meta/forward.hpp>
 #include <xsimd/types/xsimd_base.hpp>
 
-// forward declare particle
-namespace scalfmm::container
-{
-    template<typename PositionType, std::size_t PositionDim, typename InputsType, std::size_t NInputs,
-             typename OutputsType, std::size_t MOutputs, typename... Variables>
-    struct particle;
-}
 // Traits
 namespace scalfmm::meta
 {

experimental/include/scalfmm/meta/utils.hpp

@@ -17,31 +17,7 @@
 #include <type_traits>
 #include <utility>
 #include "scalfmm/meta/traits.hpp"
-
-// Forward declaration for traits support
-namespace scalfmm::container
-{
-    template<typename Derived, typename... Containers>
-    struct variadic_adaptor;
-
-    template<typename Derived, template<typename U, typename Allocator> class Container, typename... Types>
-    struct unique_variadic_container;
-
-    template<typename Derived, typename... Types>
-    struct variadic_container;
-
-    template<typename Derived, typename Tuple>
-    struct variadic_container_tuple;
-
-    template<typename ValueType, std::size_t Dimension>
-    struct point_impl;
-
-    template<typename ValueType, std::size_t Dimension>
-    struct point_proxy;
-
-    template<typename ValueType, std::size_t Dimension, typename Enable>
-    struct point;
-}   // namespace scalfmm::container
+#include "scalfmm/meta/forward.hpp"
 
 namespace scalfmm::meta
 {
@@ -121,6 +97,13 @@ namespace scalfmm::meta
     {
     };
 
+    template<typename PositionType, std::size_t PositionDim, typename InputsType, std::size_t NInputs,
+             typename OutputsType, std::size_t MOutputs, typename... Variables>
+    struct tuple_size<scalfmm::container::particle<PositionType,PositionDim,InputsType,NInputs,OutputsType,MOutputs,Variables...>>
+      : std::integral_constant<std::size_t, PositionDim+NInputs+MOutputs+sizeof...(Variables)>
+    {
+    };
+
     template<std::size_t I, typename T>
     inline constexpr auto get(T&& t) noexcept -> auto&&
     {

experimental/include/scalfmm/tools/fma_loader.hpp

@@ -739,12 +739,12 @@ namespace scalfmm::tools
                            const VALUE_T box_width)
         {
             // get the number of elements per particles in the container build with tuples.
-            // TODO : nb_elements via value_type stored in the container -> change value_type in particle container
-            constexpr int nb_elt_per_par = std::tuple_size<typename CONTAINER_T::value_type>::value;
+            using particle_type = typename CONTAINER_T::value_type;
+            constexpr int nb_elt_per_par = meta::tuple_size_v<particle_type>;
             // Not good output_values are put in input_values
-            constexpr int nb_input_per_par = CONTAINER_T::particle_type::inputs_size;
+            constexpr int nb_input_per_par = particle_type::inputs_size;
             ///  @todo check for different input and output types (double versus complexe)
-            using data_type = typename CONTAINER_T::particle_type::outputs_value_type;
+            using data_type = typename particle_type::outputs_value_type;
             //
             using particles_t = std::array<data_type, nb_elt_per_par>;
             std::vector<particles_t> particles(number_particles);