Esempio n. 1
0
size_t CoverTree<MetricType, StatisticType, MatType, RootPointPolicy>::
    SortPointSet(arma::Col<size_t>& indices,
                 arma::vec& distances,
                 const size_t childFarSetSize,
                 const size_t childUsedSetSize,
                 const size_t farSetSize)
{
  // We'll use low-level memcpy calls ourselves, just to ensure it's done
  // quickly and the way we want it to be.  Unfortunately this takes up more
  // memory than one-element swaps, but there's not a great way around that.
  const size_t bufferSize = std::min(farSetSize, childUsedSetSize);
  const size_t bigCopySize = std::max(farSetSize, childUsedSetSize);

  // Sanity check: there is no need to sort if the buffer size is going to be
  // zero.
  if (bufferSize == 0)
    return (childFarSetSize + farSetSize);

  size_t* indicesBuffer = new size_t[bufferSize];
  ElemType* distancesBuffer = new ElemType[bufferSize];

  // The start of the memory region to copy to the buffer.
  const size_t bufferFromLocation = ((bufferSize == farSetSize) ?
      (childFarSetSize + childUsedSetSize) : childFarSetSize);
  // The start of the memory region to move directly to the new place.
  const size_t directFromLocation = ((bufferSize == farSetSize) ?
      childFarSetSize : (childFarSetSize + childUsedSetSize));
  // The destination to copy the buffer back to.
  const size_t bufferToLocation = ((bufferSize == farSetSize) ?
      childFarSetSize : (childFarSetSize + farSetSize));
  // The destination of the directly moved memory region.
  const size_t directToLocation = ((bufferSize == farSetSize) ?
      (childFarSetSize + farSetSize) : childFarSetSize);

  // Copy the smaller piece to the buffer.
  memcpy(indicesBuffer, indices.memptr() + bufferFromLocation,
      sizeof(size_t) * bufferSize);
  memcpy(distancesBuffer, distances.memptr() + bufferFromLocation,
      sizeof(ElemType) * bufferSize);

  // Now move the other memory.
  memmove(indices.memptr() + directToLocation,
      indices.memptr() + directFromLocation, sizeof(size_t) * bigCopySize);
  memmove(distances.memptr() + directToLocation,
      distances.memptr() + directFromLocation, sizeof(ElemType) * bigCopySize);

  // Now copy the temporary memory to the right place.
  memcpy(indices.memptr() + bufferToLocation, indicesBuffer,
      sizeof(size_t) * bufferSize);
  memcpy(distances.memptr() + bufferToLocation, distancesBuffer,
      sizeof(ElemType) * bufferSize);

  delete[] indicesBuffer;
  delete[] distancesBuffer;

  // This returns the complete size of the far set.
  return (childFarSetSize + farSetSize);
}
Esempio n. 2
0
Teuchos::RCP<Thyra::DefaultSpmdVector<ValueType> >
wrapInTrilinosVector(arma::Col<ValueType>& col)
{
    size_t size = col.n_rows;
    Teuchos::ArrayRCP<ValueType> trilinosArray =
            Teuchos::arcp(col.memptr(), 0 /* lowerOffset */,
                          size, false /* doesn't own memory */);
    typedef Thyra::DefaultSpmdVector<ValueType> TrilinosVector;
    return Teuchos::RCP<TrilinosVector>(new TrilinosVector(
        Thyra::defaultSpmdVectorSpace<ValueType>(size),
        trilinosArray, 1 /* stride */));
}