vtkSMPTools.h

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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
 
#ifndef vtkSMPTools_h
#define vtkSMPTools_h
 
#include "vtkCommonCoreModule.h" // For export macro
#include "vtkObject.h"
 
#include "SMP/Common/vtkSMPToolsAPI.h"
#include "vtkSMPThreadLocal.h" // For Initialized
 
#include <functional>  // For std::function
#include <type_traits> // For std:::enable_if
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
namespace vtk
{
namespace detail
{
namespace smp
{
VTK_ABI_NAMESPACE_BEGIN
template <typename T>
class vtkSMPTools_Has_Initialize
{
  typedef char (&no_type)[1];
  typedef char (&yes_type)[2];
  template <typename U, void (U::*)()>
  struct V
  {
  };
  template <typename U>
  static yes_type check(V<U, &U::Initialize>*);
  template <typename U>
  static no_type check(...);
 
public:
  static bool const value = sizeof(check<T>(nullptr)) == sizeof(yes_type);
};
 
template <typename T>
class vtkSMPTools_Has_Initialize_const
{
  typedef char (&no_type)[1];
  typedef char (&yes_type)[2];
  template <typename U, void (U::*)() const>
  struct V
  {
  };
  template <typename U>
  static yes_type check(V<U, &U::Initialize>*);
  template <typename U>
  static no_type check(...);
 
public:
  static bool const value = sizeof(check<T>(0)) == sizeof(yes_type);
};
 
template <typename Functor, bool Init>
struct vtkSMPTools_FunctorInternal;
 
template <typename Functor>
struct vtkSMPTools_FunctorInternal<Functor, false>
{
  Functor& F;
  vtkSMPTools_FunctorInternal(Functor& f)
    : F(f)
  {
  }
  void Execute(vtkIdType first, vtkIdType last) { this->F(first, last); }
  void For(vtkIdType first, vtkIdType last, vtkIdType grain)
  {
    auto& SMPToolsAPI = vtkSMPToolsAPI::GetInstance();
    SMPToolsAPI.For(first, last, grain, *this);
  }
  vtkSMPTools_FunctorInternal<Functor, false>& operator=(
    const vtkSMPTools_FunctorInternal<Functor, false>&);
  vtkSMPTools_FunctorInternal(const vtkSMPTools_FunctorInternal<Functor, false>&);
};
 
template <typename Functor>
struct vtkSMPTools_FunctorInternal<Functor, true>
{
  Functor& F;
  vtkSMPThreadLocal<unsigned char> Initialized;
  vtkSMPTools_FunctorInternal(Functor& f)
    : F(f)
    , Initialized(0)
  {
  }
  void Execute(vtkIdType first, vtkIdType last)
  {
    unsigned char& inited = this->Initialized.Local();
    if (!inited)
    {
      this->F.Initialize();
      inited = 1;
    }
    this->F(first, last);
  }
  void For(vtkIdType first, vtkIdType last, vtkIdType grain)
  {
    auto& SMPToolsAPI = vtkSMPToolsAPI::GetInstance();
    SMPToolsAPI.For(first, last, grain, *this);
    this->F.Reduce();
  }
  vtkSMPTools_FunctorInternal<Functor, true>& operator=(
    const vtkSMPTools_FunctorInternal<Functor, true>&);
  vtkSMPTools_FunctorInternal(const vtkSMPTools_FunctorInternal<Functor, true>&);
};
 
template <typename Functor>
class vtkSMPTools_Lookup_For
{
  static bool const init = vtkSMPTools_Has_Initialize<Functor>::value;
 
public:
  typedef vtkSMPTools_FunctorInternal<Functor, init> type;
};
 
template <typename Functor>
class vtkSMPTools_Lookup_For<Functor const>
{
  static bool const init = vtkSMPTools_Has_Initialize_const<Functor>::value;
 
public:
  typedef vtkSMPTools_FunctorInternal<Functor const, init> type;
};
 
template <typename Iterator, typename Functor, bool Init>
struct vtkSMPTools_RangeFunctor;
 
template <typename Iterator, typename Functor>
struct vtkSMPTools_RangeFunctor<Iterator, Functor, false>
{
  Functor& F;
  Iterator& Begin;
  vtkSMPTools_RangeFunctor(Iterator& begin, Functor& f)
    : F(f)
    , Begin(begin)
  {
  }
  void operator()(vtkIdType first, vtkIdType last)
  {
    Iterator itFirst(Begin);
    std::advance(itFirst, first);
    Iterator itLast(itFirst);
    std::advance(itLast, last - first);
    this->F(itFirst, itLast);
  }
};
 
template <typename Iterator, typename Functor>
struct vtkSMPTools_RangeFunctor<Iterator, Functor, true>
{
  Functor& F;
  Iterator& Begin;
  vtkSMPTools_RangeFunctor(Iterator& begin, Functor& f)
    : F(f)
    , Begin(begin)
  {
  }
  void Initialize() { this->F.Initialize(); }
  void operator()(vtkIdType first, vtkIdType last)
  {
    Iterator itFirst(Begin);
    std::advance(itFirst, first);
    Iterator itLast(itFirst);
    std::advance(itLast, last - first);
    this->F(itFirst, itLast);
  }
  void Reduce() { this->F.Reduce(); }
};
 
template <typename Iterator, typename Functor>
class vtkSMPTools_Lookup_RangeFor
{
  static bool const init = vtkSMPTools_Has_Initialize<Functor>::value;
 
public:
  typedef vtkSMPTools_RangeFunctor<Iterator, Functor, init> type;
};
 
template <typename Iterator, typename Functor>
class vtkSMPTools_Lookup_RangeFor<Iterator, Functor const>
{
  static bool const init = vtkSMPTools_Has_Initialize_const<Functor>::value;
 
public:
  typedef vtkSMPTools_RangeFunctor<Iterator, Functor const, init> type;
};
 
template <typename T>
using resolvedNotInt = typename std::enable_if<!std::is_integral<T>::value, void>::type;
VTK_ABI_NAMESPACE_END
} // namespace smp
} // namespace detail
} // namespace vtk
#endif // DOXYGEN_SHOULD_SKIP_THIS
 
VTK_ABI_NAMESPACE_BEGIN
class VTKCOMMONCORE_EXPORT vtkSMPTools
{
public:

  template <typename Functor>
  static void For(vtkIdType first, vtkIdType last, vtkIdType grain, Functor& f)
  {
    typename vtk::detail::smp::vtkSMPTools_Lookup_For<Functor>::type fi(f);
    fi.For(first, last, grain);
  }
 
  template <typename Functor>
  static void For(vtkIdType first, vtkIdType last, vtkIdType grain, Functor const& f)
  {
    typename vtk::detail::smp::vtkSMPTools_Lookup_For<Functor const>::type fi(f);
    fi.For(first, last, grain);
  }



  template <typename Functor>
  static void For(vtkIdType first, vtkIdType last, Functor& f)
  {
    vtkSMPTools::For(first, last, 0, f);
  }
 
  template <typename Functor>
  static void For(vtkIdType first, vtkIdType last, Functor const& f)
  {
    vtkSMPTools::For(first, last, 0, f);
  }



  template <typename Iter, typename Functor>
  static vtk::detail::smp::resolvedNotInt<Iter> For(
    Iter begin, Iter end, vtkIdType grain, Functor& f)
  {
    vtkIdType size = std::distance(begin, end);
    typename vtk::detail::smp::vtkSMPTools_Lookup_RangeFor<Iter, Functor>::type fi(begin, f);
    vtkSMPTools::For(0, size, grain, fi);
  }
 
  template <typename Iter, typename Functor>
  static vtk::detail::smp::resolvedNotInt<Iter> For(
    Iter begin, Iter end, vtkIdType grain, Functor const& f)
  {
    vtkIdType size = std::distance(begin, end);
    typename vtk::detail::smp::vtkSMPTools_Lookup_RangeFor<Iter, Functor const>::type fi(begin, f);
    vtkSMPTools::For(0, size, grain, fi);
  }



  template <typename Iter, typename Functor>
  static vtk::detail::smp::resolvedNotInt<Iter> For(Iter begin, Iter end, Functor& f)
  {
    vtkSMPTools::For(begin, end, 0, f);
  }
 
  template <typename Iter, typename Functor>
  static vtk::detail::smp::resolvedNotInt<Iter> For(Iter begin, Iter end, Functor const& f)
  {
    vtkSMPTools::For(begin, end, 0, f);
  }


  static const char* GetBackend();

  static bool SetBackend(const char* backend);

  static void Initialize(int numThreads = 0);

  static int GetEstimatedNumberOfThreads();

  static int GetEstimatedDefaultNumberOfThreads();

  static void SetNestedParallelism(bool isNested);

  static bool GetNestedParallelism();

  static bool IsParallelScope();

  static bool GetSingleThread();

  struct Config
  {
    int MaxNumberOfThreads = 0;
    std::string Backend = vtk::detail::smp::vtkSMPToolsAPI::GetInstance().GetBackend();
    bool NestedParallelism = false;
 
    Config() = default;
    Config(int maxNumberOfThreads)
      : MaxNumberOfThreads(maxNumberOfThreads)
    {
    }
    Config(std::string backend)
      : Backend(backend)
    {
    }
    Config(bool nestedParallelism)
      : NestedParallelism(nestedParallelism)
    {
    }
    Config(int maxNumberOfThreads, std::string backend, bool nestedParallelism)
      : MaxNumberOfThreads(maxNumberOfThreads)
      , Backend(backend)
      , NestedParallelism(nestedParallelism)
    {
    }
#ifndef DOXYGEN_SHOULD_SKIP_THIS
    Config(vtk::detail::smp::vtkSMPToolsAPI& API)
      : MaxNumberOfThreads(API.GetInternalDesiredNumberOfThread())
      , Backend(API.GetBackend())
      , NestedParallelism(API.GetNestedParallelism())
    {
    }
#endif // DOXYGEN_SHOULD_SKIP_THIS
  };

  static constexpr vtkIdType THRESHOLD = 100000;

  template <typename T>
  static void LocalScope(Config const& config, T&& lambda)
  {
    auto& SMPToolsAPI = vtk::detail::smp::vtkSMPToolsAPI::GetInstance();
    SMPToolsAPI.LocalScope<vtkSMPTools::Config>(config, lambda);
  }

  template <typename InputIt, typename OutputIt, typename Functor>
  static void Transform(InputIt inBegin, InputIt inEnd, OutputIt outBegin, Functor transform)
  {
    auto& SMPToolsAPI = vtk::detail::smp::vtkSMPToolsAPI::GetInstance();
    SMPToolsAPI.Transform(inBegin, inEnd, outBegin, transform);
  }

  template <typename InputIt1, typename InputIt2, typename OutputIt, typename Functor>
  static void Transform(
    InputIt1 inBegin1, InputIt1 inEnd, InputIt2 inBegin2, OutputIt outBegin, Functor transform)
  {
    auto& SMPToolsAPI = vtk::detail::smp::vtkSMPToolsAPI::GetInstance();
    SMPToolsAPI.Transform(inBegin1, inEnd, inBegin2, outBegin, transform);
  }

  template <typename Iterator, typename T>
  static void Fill(Iterator begin, Iterator end, const T& value)
  {
    auto& SMPToolsAPI = vtk::detail::smp::vtkSMPToolsAPI::GetInstance();
    SMPToolsAPI.Fill(begin, end, value);
  }

  template <typename RandomAccessIterator>
  static void Sort(RandomAccessIterator begin, RandomAccessIterator end)
  {
    auto& SMPToolsAPI = vtk::detail::smp::vtkSMPToolsAPI::GetInstance();
    SMPToolsAPI.Sort(begin, end);
  }

  template <typename RandomAccessIterator, typename Compare>
  static void Sort(RandomAccessIterator begin, RandomAccessIterator end, Compare comp)
  {
    auto& SMPToolsAPI = vtk::detail::smp::vtkSMPToolsAPI::GetInstance();
    SMPToolsAPI.Sort(begin, end, comp);
  }
};
 
VTK_ABI_NAMESPACE_END
#endif
// VTK-HeaderTest-Exclude: vtkSMPTools.h