minimize save/restore allocations

src/amr/solvers/solver_ppc.hpp

@@ -5,6 +5,7 @@
 
 #include <SAMRAI/hier/Patch.h>
 
+#include "core/vector.hpp"
 
 #include "amr/messengers/hybrid_messenger.hpp"
 #include "amr/messengers/hybrid_messenger_info.hpp"
@@ -18,12 +19,13 @@
 #include "core/numerics/faraday/faraday.hpp"
 #include "core/numerics/ohm/ohm.hpp"
 
+#include "core/utilities/cellmap.hpp"
 #include "core/data/vecfield/vecfield.hpp"
 #include "core/data/grid/gridlayout_utils.hpp"
 
-
 #include <iomanip>
 #include <sstream>
+#include <tuple>
 
 namespace PHARE::solver
 {
@@ -130,7 +132,7 @@ class SolverPPC : public ISolver<AMR_Types>
                    double const currentTime, double const newTime, core::UpdaterMode mode);
 
 
-    void saveState_(level_t& level, ModelViews_t& views);
+    void saveState_(level_t const& level, ModelViews_t const& views);
     void restoreState_(level_t& level, ModelViews_t& views);
 
 
@@ -148,26 +150,32 @@ class SolverPPC : public ISolver<AMR_Types>
     };
 
 
-    // extend lifespan
-    std::unordered_map<std::string, ParticleArray> tmpDomain;
-    std::unordered_map<std::string, ParticleArray> patchGhost;
-
-    template<typename Map>
-    static void add_to(Map& map, std::string const& key, ParticleArray const& ps)
+    struct SaveState
     {
-        // vector copy drops the capacity (over allocation of the source)
-        // we want to keep the overallocation somewhat - how much to be assessed
-        ParticleArray empty{ps.box()};
-
-        if (!map.count(key))
-            map.emplace(key, empty);
-        else
-            map.at(key) = empty;
-
-        auto& v = map.at(key);
-        v.reserve(ps.capacity());
-        v.replace_from(ps);
-    }
+        bool constexpr static copy_old = false;
+        using box_t                    = core::Box<int, dimension>;
+        using CellMap_t                = core::CellMap<dimension, int>;
+        using Particle_t               = typename ParticleArray::value_type;
+        using ParticleVec_t            = core::MinimizingVector<Particle_t, copy_old>;
+
+        using SizeVec_t    = core::MinimizingVector<std::size_t, copy_old>;
+        using CellMapVec_t = core::MinimizingVector<CellMap_t, copy_old>;
+
+        auto operator()() { return std::forward_as_tuple(particles(), sizes(), maps()); }
+        auto operator()(std::size_t const& nparts, std::size_t narrays)
+        {
+            if (narrays < sizes.capacity())
+                narrays += narrays * .01;
+            return std::forward_as_tuple(particles(nparts), sizes(narrays), maps(narrays));
+        }
+
+        ParticleVec_t particles;
+        SizeVec_t sizes;
+        CellMapVec_t maps;
+    };
+
+    // extend lifespan
+    SaveState domainState, patchGhostState;
 
 }; // end solverPPC
 
@@ -214,19 +222,42 @@ void SolverPPC<HybridModel, AMR_Types>::fillMessengerInfo(
 
 
 template<typename HybridModel, typename AMR_Types>
-void SolverPPC<HybridModel, AMR_Types>::saveState_(level_t& level, ModelViews_t& views)
+void SolverPPC<HybridModel, AMR_Types>::saveState_(level_t const& level, ModelViews_t const& views)
 {
     PHARE_LOG_SCOPE(1, "SolverPPC::saveState_");
 
+    std::size_t arrays = 0, dcount = 0, pcount = 0;
     for (auto& state : views)
-    {
-        std::stringstream ss;
-        ss << state.patch->getGlobalId();
         for (auto& pop : state.ions)
         {
-            std::string const key = ss.str() + "_" + pop.name();
-            add_to(tmpDomain, key, pop.domainParticles());
-            add_to(patchGhost, key, pop.patchGhostParticles());
+            ++arrays;
+            dcount += pop.domainParticles().capacity();
+            pcount += pop.patchGhostParticles().capacity();
+        }
+
+    auto [dParts, dSizes, dMaps] = domainState(dcount, arrays);
+    auto [pParts, pSizes, pMaps] = patchGhostState(pcount, arrays);
+
+    std::size_t arr_idx = 0, doff = 0, poff = 0;
+    for (auto const& state : views)
+    {
+        for (auto const& pop : state.ions)
+        {
+            auto& dInParts = pop.domainParticles();
+            auto& pInParts = pop.patchGhostParticles();
+
+            dMaps[arr_idx] = dInParts.map();
+            pMaps[arr_idx] = pInParts.map();
+
+            dSizes[arr_idx] = dInParts.size();
+            pSizes[arr_idx] = pInParts.size();
+
+            std::copy(dInParts.data(), dInParts.data() + dSizes[arr_idx], dParts.data() + doff);
+            std::copy(pInParts.data(), pInParts.data() + pSizes[arr_idx], pParts.data() + poff);
+
+            doff += dSizes[arr_idx];
+            poff += pSizes[arr_idx];
+            ++arr_idx;
         }
     }
 }
@@ -236,15 +267,22 @@ void SolverPPC<HybridModel, AMR_Types>::restoreState_(level_t& level, ModelViews
 {
     PHARE_LOG_SCOPE(1, "SolverPPC::restoreState_");
 
+    auto const [dInParts, dSizes, dMaps] = domainState();
+    auto const [pInParts, pSizes, pMaps] = patchGhostState();
+
+    std::size_t arr_idx = 0, doff = 0, poff = 0;
     for (auto& state : views)
     {
-        std::stringstream ss;
-        ss << state.patch->getGlobalId();
-
         for (auto& pop : state.ions)
         {
-            pop.domainParticles()     = std::move(tmpDomain.at(ss.str() + "_" + pop.name()));
-            pop.patchGhostParticles() = std::move(patchGhost.at(ss.str() + "_" + pop.name()));
+            pop.domainParticles().replace_from(dInParts.data() + doff, dSizes[arr_idx],
+                                               dMaps[arr_idx]);
+            pop.patchGhostParticles().replace_from(pInParts.data() + poff, pSizes[arr_idx],
+                                                   pMaps[arr_idx]);
+
+            doff += dSizes[arr_idx];
+            poff += pSizes[arr_idx];
+            ++arr_idx;
         }
     }
 }

src/core/data/particles/particle_array.hpp

@@ -41,14 +41,7 @@ class ParticleArray
 
 
 public:
-    ParticleArray(box_t box)
-        : box_{box}
-        , cellMap_{box_}
-    {
-        assert(box_.size() > 0);
-    }
-
-    ParticleArray(box_t box, std::size_t size)
+    ParticleArray(box_t box = box_t{}, std::size_t size = 0)
         : particles_(size)
         , box_{box}
         , cellMap_{box_}
@@ -80,6 +73,9 @@ class ParticleArray
         return (this->particles_ == that.particles_);
     }
 
+    NO_DISCARD auto data() const { return particles_.data(); }
+    NO_DISCARD auto data() { return particles_.data(); }
+
     NO_DISCARD auto begin() const { return particles_.begin(); }
     NO_DISCARD auto begin() { return particles_.begin(); }
 
@@ -235,6 +231,7 @@ class ParticleArray
     NO_DISCARD auto& vector() const { return particles_; }
 
     auto& box() const { return box_; }
+    auto& map() const { return cellMap_; }
 
 
     auto& replace_from(ParticleArray const& that)
@@ -247,6 +244,14 @@ class ParticleArray
         this->cellMap_ = that.cellMap_;
         return *this;
     }
+    auto& replace_from(Particle_t const* particles, std::size_t size, CellMap_t const& map)
+    {
+        this->resize(size);
+        this->cellMap_ = map;
+        this->box_     = map.box();
+        std::copy(particles, particles + size, particles_.data());
+        return *this;
+    }
 
 
 private:

src/core/def.hpp

@@ -44,6 +44,8 @@ NO_DISCARD bool isSettable(auto const&... args)
     return (check(args) && ...);
 }
 
+
+
 } // namespace PHARE::core
 
 #endif // PHARE_CORE_DEF_HPP

src/core/utilities/cellmap.hpp

@@ -31,7 +31,7 @@ class CellMap
 
 
 public:
-    CellMap(Box<cell_index_t, dim> box)
+    CellMap(Box<cell_index_t, dim> box = {})
         : box_{box}
         , cellIndexes_{box.shape().template toArray<std::uint32_t>()}
     {

src/core/vector.hpp

@@ -0,0 +1,55 @@
+#ifndef PHARE_CORE_VECTOR_HPP
+#define PHARE_CORE_VECTOR_HPP
+
+#include <vector>
+#include <cstdint>
+#include "core/utilities/span.hpp"
+
+namespace PHARE::core
+{
+
+
+template<typename T, bool copy_old_ = true>
+struct MinimizingVector
+{
+    template<bool copy_old = copy_old_>
+    auto& get(std::size_t const& s)
+    {
+        if (s < v.capacity() * percentile)
+            ++_c;
+        else
+            _c = 0;
+
+        if (_c == period)
+        {
+            std::vector<T> r(v.capacity() * realloc_to);
+            if constexpr (copy_old)
+                r = v;
+            v  = std::move(r);
+            _c = 0;
+        }
+
+        v.resize(s);
+        return v;
+    }
+
+    auto size() const { return v.size(); }
+    auto capacity() const { return v.capacity(); }
+    auto& operator()() { return v; }
+    auto& operator()() const { return v; }
+    auto& operator()(std::size_t const& s) { return get(s); }
+
+    double const percentile  = .80;
+    double const realloc_to  = .90;
+    std::size_t const period = 100;
+
+    std::vector<T> v{};
+    std::uint16_t _c = 0;
+};
+
+
+
+
+} // namespace PHARE::core
+
+#endif // PHARE_CORE_VECTOR_HPP