ForLoopRanges.h

// -*- tab-width: 2; indent-tabs-mode: nil; coding: utf-8-with-signature -*-
//-----------------------------------------------------------------------------
// Copyright 2000-2025 CEA (www.cea.fr) IFPEN (www.ifpenergiesnouvelles.com)
// See the top-level COPYRIGHT file for details.
// SPDX-License-Identifier: Apache-2.0
//-----------------------------------------------------------------------------
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/* ForLoopRanges.h                                             (C) 2000-2025 */
/*                                                                           */
/* Intervalles d'itérations pour les boucles.                                */
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#ifndef ARCANE_UTILS_FORLOOPRANGES_H
#define ARCANE_UTILS_FORLOOPRANGES_H
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#include "arcane/utils/ArrayBounds.h"
 
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namespace Arcane::impl
{
/*!
 * \brief Classe pour appliquer la finalisation des réductions.
 */
class HostReducerHelper
{
 public:
 
  //! Applique les fonctors des arguments additionnels.
  template <typename... ReducerArgs> static inline void
  applyReducerArgs(ReducerArgs&... reducer_args)
  {
    // Applique les réductions
    (reducer_args._internalReduceHost(), ...);
  }
};
}
 
namespace Arcane
{
 
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/*!
 * \brief Intervalle d'itération pour une boucle.
 */
class ForLoopRange
{
 public:
 
  //! Créé un interval entre *[lower_bound,lower_bound+size[*
  ForLoopRange(Int32 lower_bound, Int32 size)
  : m_lower_bound(lower_bound)
  , m_size(size)
  {}
  //! Créé un interval entre *[0,size[*
  ForLoopRange(Int32 size)
  : m_lower_bound(0)
  , m_size(size)
  {}
 
 public:
 
  constexpr Int32 lowerBound() const { return m_lower_bound; }
  constexpr Int32 size() const { return m_size; }
  constexpr Int32 upperBound() const { return m_lower_bound + m_size; }
 
 private:
 
  Int32 m_lower_bound;
  Int32 m_size;
};
 
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/*!
 * \brief Interval d'itération simple.
 *
 * Les indices de début pour chaque dimension commencent à 0.
 */
template <int N, typename IndexType_>
class SimpleForLoopRanges
{
  friend class ComplexForLoopRanges<N>;
 
 public:
 
  using ArrayBoundsType = ArrayBounds<typename MDDimType<N>::DimType>;
  using ArrayIndexType = typename ArrayBoundsType::IndexType;
  using IndexType = ArrayIndexType;
 
 public:
 
  explicit SimpleForLoopRanges(std::array<Int32, N> b)
  : m_bounds(b)
  {}
  SimpleForLoopRanges(ArrayBoundsType b)
  : m_bounds(b)
  {}
 
 public:
 
  template <Int32 I> constexpr Int32 lowerBound() const { return 0; }
  template <Int32 I> constexpr Int32 upperBound() const { return m_bounds.template constExtent<I>(); }
  template <Int32 I> constexpr Int32 extent() const { return m_bounds.template constExtent<I>(); }
  constexpr Int64 nbElement() const { return m_bounds.nbElement(); }
  constexpr ArrayIndexType getIndices(Int32 i) const { return m_bounds.getIndices(i); }
 
 private:
 
  ArrayBoundsType m_bounds;
};
 
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/*!
 * \internal
 * \brief Interval d'itération complexe.
 *
 * Les indices de début pour chaque dimension sont spécifiés \a lower et
 * le nombre d'éléments dans chaque dimension par \a extents.
 */
template <int N, typename IndexType_>
class ComplexForLoopRanges
{
 public:
 
  using ArrayBoundsType = ArrayBounds<typename MDDimType<N>::DimType>;
  using ArrayIndexType = typename ArrayBoundsType::IndexType;
  using IndexType = ArrayIndexType;
 
 public:
 
  ComplexForLoopRanges(ArrayBoundsType lower, ArrayBoundsType extents)
  : m_lower_bounds(lower.asStdArray())
  , m_extents(extents)
  {}
  ComplexForLoopRanges(const SimpleForLoopRanges<N>& bounds)
  : m_extents(bounds.m_bounds)
  {}
 
 public:
 
  template <Int32 I> constexpr Int32 lowerBound() const { return m_lower_bounds[I]; }
  template <Int32 I> constexpr Int32 upperBound() const { return m_lower_bounds[I] + m_extents.template constExtent<I>(); }
  template <Int32 I> constexpr Int32 extent() const { return m_extents.template constExtent<I>(); }
  constexpr Int64 nbElement() const { return m_extents.nbElement(); }
  constexpr ArrayIndexType getIndices(Int32 i) const
  {
    auto x = m_extents.getIndices(i);
    x.add(m_lower_bounds);
    return x;
  }
  constexpr ArrayBoundsType extents() const { return m_extents; }
 
 private:
 
  ArrayIndexType m_lower_bounds;
  ArrayBoundsType m_extents;
};
 
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//! Créé un intervalle d'itération [0,n1[
inline SimpleForLoopRanges<1>
makeLoopRanges(Int32 n1)
{
  using BoundsType = SimpleForLoopRanges<1>::ArrayBoundsType;
  using ArrayExtentType = typename BoundsType::ArrayExtentType;
 
  return BoundsType(ArrayExtentType(n1));
}
 
//! Créé un intervalle d'itération [0,n1[,[0,n2[
inline SimpleForLoopRanges<2>
makeLoopRanges(Int32 n1, Int32 n2)
{
  using BoundsType = SimpleForLoopRanges<2>::ArrayBoundsType;
  using ArrayExtentType = typename BoundsType::ArrayExtentType;
 
  return BoundsType(ArrayExtentType(n1, n2));
}
 
//! Créé un intervalle d'itération [0,n1[,[0,n2[,[0,n3[
inline SimpleForLoopRanges<3>
makeLoopRanges(Int32 n1, Int32 n2, Int32 n3)
{
  using BoundsType = SimpleForLoopRanges<3>::ArrayBoundsType;
  using ArrayExtentType = typename BoundsType::ArrayExtentType;
 
  return BoundsType(ArrayExtentType(n1, n2, n3));
}
 
//! Créé un intervalle d'itération [0,n1[,[0,n2[,[0,n3[,[0,n4[
inline SimpleForLoopRanges<4>
makeLoopRanges(Int32 n1, Int32 n2, Int32 n3, Int32 n4)
{
  using BoundsType = SimpleForLoopRanges<4>::ArrayBoundsType;
  using ArrayExtentType = typename BoundsType::ArrayExtentType;
 
  return BoundsType(ArrayExtentType(n1, n2, n3, n4));
}
 
//! Créé un intervalle d'itération dans ℕ.
inline ComplexForLoopRanges<1>
makeLoopRanges(ForLoopRange n1)
{
  using BoundsType = ComplexForLoopRanges<1>::ArrayBoundsType;
  using ArrayExtentType = typename BoundsType::ArrayExtentType;
 
  BoundsType lower_bounds(ArrayExtentType(n1.lowerBound()));
  BoundsType sizes(ArrayExtentType(n1.size()));
  return { lower_bounds, sizes };
}
 
//! Créé un intervalle d'itération dans ℕ².
inline ComplexForLoopRanges<2>
makeLoopRanges(ForLoopRange n1, ForLoopRange n2)
{
  using BoundsType = ComplexForLoopRanges<2>::ArrayBoundsType;
  using ArrayExtentType = typename BoundsType::ArrayExtentType;
 
  BoundsType lower_bounds(ArrayExtentType(n1.lowerBound(), n2.lowerBound()));
  BoundsType sizes(ArrayExtentType(n1.size(), n2.size()));
  return { lower_bounds, sizes };
}
 
//! Créé un intervalle d'itération dans ℕ³.
inline ComplexForLoopRanges<3>
makeLoopRanges(ForLoopRange n1, ForLoopRange n2, ForLoopRange n3)
{
  using BoundsType = ComplexForLoopRanges<3>::ArrayBoundsType;
  using ArrayExtentType = typename BoundsType::ArrayExtentType;
 
  BoundsType lower_bounds(ArrayExtentType(n1.lowerBound(), n2.lowerBound(), n3.lowerBound()));
  BoundsType sizes(ArrayExtentType(n1.size(), n2.size(), n3.size()));
  return { lower_bounds, sizes };
}
 
//! Créé un intervalle d'itération dans ℕ⁴.
inline ComplexForLoopRanges<4>
makeLoopRanges(ForLoopRange n1, ForLoopRange n2, ForLoopRange n3, ForLoopRange n4)
{
  using BoundsType = ComplexForLoopRanges<4>::ArrayBoundsType;
  using ArrayExtentType = typename BoundsType::ArrayExtentType;
 
  BoundsType lower_bounds(ArrayExtentType(n1.lowerBound(), n2.lowerBound(), n3.lowerBound(), n4.lowerBound()));
  BoundsType sizes(ArrayExtentType(n1.size(), n2.size(), n3.size(), n4.size()));
  return { lower_bounds, sizes };
}
 
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//! Applique le fonctor \a func sur une boucle 1D.
template <typename IndexType, template <int T, typename> class LoopBoundType,
          typename Lambda, typename... ReducerArgs>
inline void
arcaneSequentialFor(LoopBoundType<1, IndexType> bounds, const Lambda& func, ReducerArgs... reducer_args)
{
  for (Int32 i0 = bounds.template lowerBound<0>(); i0 < bounds.template upperBound<0>(); ++i0)
    func(MDIndex<1>(i0), reducer_args...);
  impl::HostReducerHelper::applyReducerArgs(reducer_args...);
}
 
//! Applique le fonctor \a func sur une boucle 2D.
template <typename IndexType, template <int T, typename> class LoopBoundType, typename Lambda> inline void
arcaneSequentialFor(LoopBoundType<2, IndexType> bounds, const Lambda& func)
{
  for (Int32 i0 = bounds.template lowerBound<0>(); i0 < bounds.template upperBound<0>(); ++i0)
    for (Int32 i1 = bounds.template lowerBound<1>(); i1 < bounds.template upperBound<1>(); ++i1)
      func(MDIndex<2>(i0, i1));
}
 
//! Applique le fonctor \a func sur une boucle 3D.
template <typename IndexType, template <int T, typename> class LoopBoundType, typename Lambda> inline void
arcaneSequentialFor(LoopBoundType<3, IndexType> bounds, const Lambda& func)
{
  for (Int32 i0 = bounds.template lowerBound<0>(); i0 < bounds.template upperBound<0>(); ++i0)
    for (Int32 i1 = bounds.template lowerBound<1>(); i1 < bounds.template upperBound<1>(); ++i1)
      for (Int32 i2 = bounds.template lowerBound<2>(); i2 < bounds.template upperBound<2>(); ++i2)
        func(MDIndex<3>(i0, i1, i2));
}
 
//! Applique le fonctor \a func sur une boucle 4D.
template <typename IndexType, template <int, typename> class LoopBoundType, typename Lambda> inline void
arcaneSequentialFor(LoopBoundType<4, IndexType> bounds, const Lambda& func)
{
  for (Int32 i0 = bounds.template lowerBound<0>(); i0 < bounds.template upperBound<0>(); ++i0)
    for (Int32 i1 = bounds.template lowerBound<1>(); i1 < bounds.template upperBound<1>(); ++i1)
      for (Int32 i2 = bounds.template lowerBound<2>(); i2 < bounds.template upperBound<2>(); ++i2)
        for (Int32 i3 = bounds.template lowerBound<3>(); i3 < bounds.template upperBound<3>(); ++i3)
          func(MDIndex<4>(i0, i1, i2, i3));
}
 
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} // End namespace Arcane
 
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#endif