copyAuxStoreThinned.cxx

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
#include "AthContainers/tools/copyAuxStoreThinned.h"
#include "AthContainers/AuxTypeRegistry.h"
#include "AthContainersInterfaces/IConstAuxStore.h"
#include "AthContainersInterfaces/IAuxStore.h"
#include "AthContainersInterfaces/IAuxStoreIO.h"
#include "AthenaKernel/ThinningDecisionBase.h"
#include "CxxUtils/no_sanitize_undefined.h"
#include "CxxUtils/FloatCompressor.h"
#include <vector>
 
 
namespace {
 
 
class TempInterface
  : public SG::AuxVectorData
{
public:
  TempInterface (size_t size) : m_size (size) {}
  using AuxVectorData::setStore;
 
  virtual size_t size_v() const { return m_size; }
  virtual size_t capacity_v() const { return m_size; }
 
private:
  size_t m_size;
};
 
 
} // anonymous namespace
 
 
namespace SG {
 
 
void copyAuxStoreThinned NO_SANITIZE_UNDEFINED
   (const SG::IConstAuxStore& orig,
    SG::IAuxStore& copy,
    const SG::ThinningInfo* info)
{
  size_t size = orig.size();
  if (size == 0) {
    copy.resize(0);
    return;
  }
 
  const ThinningDecisionBase* dec = info ? info->m_decision : nullptr;
 
  size_t nremaining = dec ? dec->thinnedSize() : size;
  if( nremaining == 0) {
    copy.resize(0);
    return;
  }
 
  // Access the auxiliary type registry:
  SG::AuxTypeRegistry& r = SG::AuxTypeRegistry::instance();
 
  // The auxiliary IDs that the original container has:
  SG::auxid_set_t auxids = orig.getAuxIDs();
 
  SG::auxid_set_t dyn_auxids;
  SG::auxid_set_t sel_auxids;
  if (const IAuxStoreIO* iio = dynamic_cast<const IAuxStoreIO*> (&orig)) {
    dyn_auxids = iio->getDynamicAuxIDs();
    sel_auxids = iio->getSelectedAuxIDs();
  }
 
  SG::auxid_set_t new_auxids = copy.getAuxIDs();
 
  copy.resize (nremaining);
 
  // Loop over all the variables of the original container:
  for (SG::auxid_t auxid : auxids) {
    // Skip null auxids (happens if we don't have the dictionary)
    if(auxid == SG::null_auxid) continue;
 
    // Skip linked variables (they'll be handled when we copy the variable
    // from which they're linked).
    if (r.isLinked (auxid)) continue;
 
    // Skip non-selected dynamic variables.
    // Handle variable vetoes requested via ThinningInfo.
    // We want to allow vetoing a variable if it's defined
    // as a dynamic variable in the source source, or if it doesn't
    // exist in the destination source (in which case it will be
    // dynamic there).  The latter case happens for example when
    // we save a static store object as the AuxContainerBaseClass
    // in order to make all variables dynamic.
    if (dyn_auxids.test(auxid) || !new_auxids.test(auxid)) {
      if (info) {
        if (info->vetoed(auxid)) continue;
      }
    }
 
    // Also check for a veto requested through the store selection interface.
    // (But this shouldn't really be used anymore.)
    if (dyn_auxids.test(auxid) && !sel_auxids.test(auxid)) {
      continue;
    }
 
    // Access the source variable:
    const void* src = orig.getData (auxid);
 
    if (!src) continue;
 
    // FIXME: Do this via proper interfaces.
    if (const IAuxStoreIO* iio = dynamic_cast<const IAuxStoreIO*> (&orig))
    {
      const std::type_info* typ = iio->getIOType (auxid);
      if (strstr (typ->name(), "PackedContainer") != nullptr) {
        // This cast gets a warning from the undefined behavior sanitizer
        // in gcc6.  Done like this deliberately for now, so suppress ubsan
        // checking for this function.
        const PackedParameters& parms =
          reinterpret_cast<const PackedContainer<int>* > (iio->getIOData (auxid))->parms();
        copy.setOption (auxid, AuxDataOption ("nbits", parms.nbits()));
        copy.setOption (auxid, AuxDataOption ("float", parms.isFloat()));
        copy.setOption (auxid, AuxDataOption ("signed", parms.isSigned()));
        copy.setOption (auxid, AuxDataOption ("rounding", parms.rounding()));
        copy.setOption (auxid, AuxDataOption ("nmantissa", parms.nmantissa()));
        copy.setOption (auxid, AuxDataOption ("scale", parms.scale()));
      }
    }
 
    // Get the element size, type name and compression info for the current auxid
    // This information is later passed to the helper function lossyFloatCompress
    const size_t eltSize{ r.getEltSize(auxid) };
    const std::string typeName{ r.getTypeName(auxid) };
    const unsigned int nmantissa{ info != nullptr ? info->compression(auxid) : 0 };
 
    // Create the target variable:
    void* dst = copy.getData (auxid, nremaining, nremaining);
 
    // Also create a linked variable if needed.
    SG::auxid_t linked_auxid = r.linkedVariable (auxid);
    if (linked_auxid != null_auxid) {
      const IAuxTypeVector* v = orig.linkedVector (auxid);
      if (v) {
        size_t sz = v->size();
        copy.getData (linked_auxid, 0, sz);
      }
    }
 
    TempInterface srciface (orig.size());
    srciface.setStore (&orig);
    TempInterface dstiface (copy.size());
    dstiface.setStore (&copy);
 
    // Copy over all elements.
    if (nremaining == size) {
      // No thinning.
      r.copyForOutput (auxid, dstiface, 0, srciface, 0, size);
    }
    else {
      // Some elements are thinned.
      for (std::size_t isrc = 0, idst = 0; isrc < size; ++isrc) {
        if (!dec || !dec->thinned(isrc)) {
          r.copyForOutput (auxid, dstiface, idst, srciface, isrc, 1);
          ++idst;
        }
      }
    }
    // Apply lossy float compression here (in-place).
    // Maybe it would be better to do this via the registry during copy.
    lossyFloatCompress(dst, 0, nremaining, eltSize, typeName, nmantissa);
  }
}
 
void lossyFloatCompress (void* dst,
                         const std::size_t idst,
                         const std::size_t n,
                         const std::size_t eltSize,
                         const std::string& typeName,
                         const unsigned int nmantissa)
{
  // Check if there is anything to be done
  // Total number of explicit mantissa bits for a 32 bit float is 23
  // 0 is used to denote no compression should be applied to the variable
  static const unsigned int NMANTISSA_MAX = 23;
  if (nmantissa == 0 || nmantissa >= NMANTISSA_MAX) return;
 
  // Setup all possible compressors: done only once
  static const std::vector<CxxUtils::FloatCompressor> compressors = [] {
    std::vector<CxxUtils::FloatCompressor> result;
    result.reserve(NMANTISSA_MAX);
    for (std::size_t idx = 0; idx < NMANTISSA_MAX; ++idx)
      result.emplace_back(idx);
    return result;
  }();
 
  // Get the pointer to the memory
  char* eltPtr = reinterpret_cast<char*>(dst) + idst*eltSize;
 
  // This is where we apply in-place lossy float compression
  if(typeName == "float") {
    // cppcheck-suppress invalidPointerCast
    float* f = reinterpret_cast<float*> (eltPtr);
    for (size_t i = 0; i < n; i++) {
      *f = compressors[nmantissa].reduceFloatPrecision(*f);
      ++f;
    }
  } else if (typeName == "std::vector<float>"){
    for (size_t i = 0; i < n; i++) {
      std::vector<float> &vals = *(reinterpret_cast<std::vector<float>*>(eltPtr));
      for(auto &val: vals) {
        val = compressors[nmantissa].reduceFloatPrecision(val);
      }
      eltPtr += eltSize;
    }
  }
}
 
} // namespace SG