Chris@16: // Copyright (C) 2004 The Trustees of Indiana University.
Chris@16: // Copyright (C) 2005-2006 Douglas Gregor <doug.gregor -at- gmail.com>
Chris@16: 
Chris@16: // Use, modification and distribution is subject to the Boost Software
Chris@16: // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  Authors: Douglas Gregor
Chris@16: //           Andrew Lumsdaine
Chris@16: 
Chris@16: /** @file operations.hpp
Chris@16:  *
Chris@16:  *  This header provides a mapping from function objects to @c MPI_Op
Chris@16:  *  constants used in MPI collective operations. It also provides
Chris@16:  *  several new function object types not present in the standard @c
Chris@16:  *  <functional> header that have direct mappings to @c MPI_Op.
Chris@16:  */
Chris@16: #ifndef BOOST_MPI_IS_MPI_OP_HPP
Chris@16: #define BOOST_MPI_IS_MPI_OP_HPP
Chris@16: 
Chris@16: #include <boost/mpi/config.hpp>
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/mpl/and.hpp>
Chris@16: #include <boost/mpi/datatype.hpp>
Chris@16: #include <boost/utility/enable_if.hpp>
Chris@16: #include <functional>
Chris@16: 
Chris@16: namespace boost { namespace mpi {
Chris@16: 
Chris@16: template<typename Op, typename T> struct is_mpi_op;
Chris@16: 
Chris@16: /**
Chris@16:  * @brief Determine if a function object type is commutative.
Chris@16:  *
Chris@16:  * This trait determines if an operation @c Op is commutative when
Chris@16:  * applied to values of type @c T. Parallel operations such as @c
Chris@16:  * reduce and @c prefix_sum can be implemented more efficiently with
Chris@16:  * commutative operations. To mark an operation as commutative, users
Chris@16:  * should specialize @c is_commutative and derive from the class @c
Chris@16:  * mpl::true_.
Chris@16:  */
Chris@16: template<typename Op, typename T>
Chris@16: struct is_commutative : public mpl::false_ { };
Chris@16: 
Chris@16: /**************************************************************************
Chris@16:  * Function objects for MPI operations not in <functional> header         *
Chris@16:  **************************************************************************/
Chris@16: 
Chris@16: /**
Chris@16:  *  @brief Compute the maximum of two values.
Chris@16:  *
Chris@16:  *  This binary function object computes the maximum of the two values
Chris@16:  *  it is given. When used with MPI and a type @c T that has an
Chris@16:  *  associated, built-in MPI data type, translates to @c MPI_MAX.
Chris@16:  */
Chris@16: template<typename T>
Chris@16: struct maximum : public std::binary_function<T, T, T>
Chris@16: {
Chris@16:   /** @returns the maximum of x and y. */
Chris@16:   const T& operator()(const T& x, const T& y) const
Chris@16:   {
Chris@16:     return x < y? y : x;
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: /**
Chris@16:  *  @brief Compute the minimum of two values.
Chris@16:  *
Chris@16:  *  This binary function object computes the minimum of the two values
Chris@16:  *  it is given. When used with MPI and a type @c T that has an
Chris@16:  *  associated, built-in MPI data type, translates to @c MPI_MIN.
Chris@16:  */
Chris@16: template<typename T>
Chris@16: struct minimum : public std::binary_function<T, T, T>
Chris@16: {
Chris@16:   /** @returns the minimum of x and y. */
Chris@16:   const T& operator()(const T& x, const T& y) const
Chris@16:   {
Chris@16:     return x < y? x : y;
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: /**
Chris@16:  *  @brief Compute the bitwise AND of two integral values.
Chris@16:  *
Chris@16:  *  This binary function object computes the bitwise AND of the two
Chris@16:  *  values it is given. When used with MPI and a type @c T that has an
Chris@16:  *  associated, built-in MPI data type, translates to @c MPI_BAND.
Chris@16:  */
Chris@16: template<typename T>
Chris@16: struct bitwise_and : public std::binary_function<T, T, T>
Chris@16: {
Chris@16:   /** @returns @c x & y. */
Chris@16:   T operator()(const T& x, const T& y) const
Chris@16:   {
Chris@16:     return x & y;
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: /**
Chris@16:  *  @brief Compute the bitwise OR of two integral values.
Chris@16:  *
Chris@16:  *  This binary function object computes the bitwise OR of the two
Chris@16:  *  values it is given. When used with MPI and a type @c T that has an
Chris@16:  *  associated, built-in MPI data type, translates to @c MPI_BOR.
Chris@16:  */
Chris@16: template<typename T>
Chris@16: struct bitwise_or : public std::binary_function<T, T, T>
Chris@16: {
Chris@16:   /** @returns the @c x | y. */
Chris@16:   T operator()(const T& x, const T& y) const
Chris@16:   {
Chris@16:     return x | y;
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: /**
Chris@16:  *  @brief Compute the logical exclusive OR of two integral values.
Chris@16:  *
Chris@16:  *  This binary function object computes the logical exclusive of the
Chris@16:  *  two values it is given. When used with MPI and a type @c T that has
Chris@16:  *  an associated, built-in MPI data type, translates to @c MPI_LXOR.
Chris@16:  */
Chris@16: template<typename T>
Chris@16: struct logical_xor : public std::binary_function<T, T, T>
Chris@16: {
Chris@16:   /** @returns the logical exclusive OR of x and y. */
Chris@16:   T operator()(const T& x, const T& y) const
Chris@16:   {
Chris@16:     return (x || y) && !(x && y);
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: /**
Chris@16:  *  @brief Compute the bitwise exclusive OR of two integral values.
Chris@16:  *
Chris@16:  *  This binary function object computes the bitwise exclusive OR of
Chris@16:  *  the two values it is given. When used with MPI and a type @c T that
Chris@16:  *  has an associated, built-in MPI data type, translates to @c
Chris@16:  *  MPI_BXOR.
Chris@16:  */
Chris@16: template<typename T>
Chris@16: struct bitwise_xor : public std::binary_function<T, T, T>
Chris@16: {
Chris@16:   /** @returns @c x ^ y. */
Chris@16:   T operator()(const T& x, const T& y) const
Chris@16:   {
Chris@16:     return x ^ y;
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: /**************************************************************************
Chris@16:  * MPI_Op queries                                                         *
Chris@16:  **************************************************************************/
Chris@16: 
Chris@16: /**
Chris@16:  *  @brief Determine if a function object has an associated @c MPI_Op.
Chris@16:  *
Chris@16:  *  This trait determines if a function object type @c Op, when used
Chris@16:  *  with argument type @c T, has an associated @c MPI_Op. If so, @c
Chris@16:  *  is_mpi_op<Op,T> will derive from @c mpl::false_ and will
Chris@16:  *  contain a static member function @c op that takes no arguments but
Chris@16:  *  returns the associated @c MPI_Op value. For instance, @c
Chris@16:  *  is_mpi_op<std::plus<int>,int>::op() returns @c MPI_SUM.
Chris@16:  *
Chris@16:  *  Users may specialize @c is_mpi_op for any other class templates
Chris@16:  *  that map onto operations that have @c MPI_Op equivalences, such as
Chris@16:  *  bitwise OR, logical and, or maximum. However, users are encouraged
Chris@16:  *  to use the standard function objects in the @c functional and @c
Chris@16:  *  boost/mpi/operations.hpp headers whenever possible. For
Chris@16:  *  function objects that are class templates with a single template
Chris@16:  *  parameter, it may be easier to specialize @c is_builtin_mpi_op.
Chris@16:  */
Chris@16: template<typename Op, typename T>
Chris@16: struct is_mpi_op : public mpl::false_ { };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<typename T>
Chris@16: struct is_mpi_op<maximum<T>, T>
Chris@16:   : public boost::mpl::or_<is_mpi_integer_datatype<T>,
Chris@16:                            is_mpi_floating_point_datatype<T> >
Chris@16: {
Chris@16:   static MPI_Op op() { return MPI_MAX; }
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<typename T>
Chris@16: struct is_mpi_op<minimum<T>, T>
Chris@16:   : public boost::mpl::or_<is_mpi_integer_datatype<T>,
Chris@16:                            is_mpi_floating_point_datatype<T> >
Chris@16: {
Chris@16:   static MPI_Op op() { return MPI_MIN; }
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<typename T>
Chris@16:  struct is_mpi_op<std::plus<T>, T>
Chris@16:   : public boost::mpl::or_<is_mpi_integer_datatype<T>,
Chris@16:                            is_mpi_floating_point_datatype<T>,
Chris@16:                            is_mpi_complex_datatype<T> >
Chris@16: {
Chris@16:   static MPI_Op op() { return MPI_SUM; }
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<typename T>
Chris@16:  struct is_mpi_op<std::multiplies<T>, T>
Chris@16:   : public boost::mpl::or_<is_mpi_integer_datatype<T>,
Chris@16:                            is_mpi_floating_point_datatype<T>,
Chris@16:                            is_mpi_complex_datatype<T> >
Chris@16: {
Chris@16:   static MPI_Op op() { return MPI_PROD; }
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<typename T>
Chris@16:  struct is_mpi_op<std::logical_and<T>, T>
Chris@16:   : public boost::mpl::or_<is_mpi_integer_datatype<T>,
Chris@16:                            is_mpi_logical_datatype<T> >
Chris@16: {
Chris@16:   static MPI_Op op() { return MPI_LAND; }
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<typename T>
Chris@16:  struct is_mpi_op<std::logical_or<T>, T>
Chris@16:   : public boost::mpl::or_<is_mpi_integer_datatype<T>,
Chris@16:                            is_mpi_logical_datatype<T> >
Chris@16: {
Chris@16:   static MPI_Op op() { return MPI_LOR; }
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<typename T>
Chris@16:  struct is_mpi_op<logical_xor<T>, T>
Chris@16:   : public boost::mpl::or_<is_mpi_integer_datatype<T>,
Chris@16:                            is_mpi_logical_datatype<T> >
Chris@16: {
Chris@16:   static MPI_Op op() { return MPI_LXOR; }
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<typename T>
Chris@16:  struct is_mpi_op<bitwise_and<T>, T>
Chris@16:   : public boost::mpl::or_<is_mpi_integer_datatype<T>,
Chris@16:                            is_mpi_byte_datatype<T> >
Chris@16: {
Chris@16:   static MPI_Op op() { return MPI_BAND; }
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<typename T>
Chris@16:  struct is_mpi_op<bitwise_or<T>, T>
Chris@16:   : public boost::mpl::or_<is_mpi_integer_datatype<T>,
Chris@16:                            is_mpi_byte_datatype<T> >
Chris@16: {
Chris@16:   static MPI_Op op() { return MPI_BOR; }
Chris@16: };
Chris@16: 
Chris@16: /// INTERNAL ONLY
Chris@16: template<typename T>
Chris@16:  struct is_mpi_op<bitwise_xor<T>, T>
Chris@16:   : public boost::mpl::or_<is_mpi_integer_datatype<T>,
Chris@16:                            is_mpi_byte_datatype<T> >
Chris@16: {
Chris@16:   static MPI_Op op() { return MPI_BXOR; }
Chris@16: };
Chris@16: 
Chris@16: namespace detail {
Chris@16:   // A helper class used to create user-defined MPI_Ops
Chris@16:   template<typename Op, typename T>
Chris@16:   class user_op
Chris@16:   {
Chris@16:   public:
Chris@16:     explicit user_op(Op& op)
Chris@16:     {
Chris@16:       BOOST_MPI_CHECK_RESULT(MPI_Op_create,
Chris@16:                              (&user_op<Op, T>::perform,
Chris@16:                               is_commutative<Op, T>::value,
Chris@16:                               &mpi_op));
Chris@16: 
Chris@16:       op_ptr = &op;
Chris@16:     }
Chris@16: 
Chris@16:     ~user_op()
Chris@16:     {
Chris@16:       if (std::uncaught_exception()) {
Chris@16:         // Ignore failure cases: there are obviously other problems
Chris@16:         // already, and we don't want to cause program termination if
Chris@16:         // MPI_Op_free fails.
Chris@16:         MPI_Op_free(&mpi_op);
Chris@16:       } else {
Chris@16:         BOOST_MPI_CHECK_RESULT(MPI_Op_free, (&mpi_op));
Chris@16:       }
Chris@16:     }
Chris@16: 
Chris@16:     MPI_Op& get_mpi_op()
Chris@16:     {
Chris@16:       return mpi_op;
Chris@16:     }
Chris@16: 
Chris@16:   private:
Chris@16:     MPI_Op mpi_op;
Chris@16:     static Op* op_ptr;
Chris@16: 
Chris@16:     static void BOOST_MPI_CALLING_CONVENTION perform(void* vinvec, void* voutvec, int* plen, MPI_Datatype*)
Chris@16:     {
Chris@16:       T* invec = static_cast<T*>(vinvec);
Chris@16:       T* outvec = static_cast<T*>(voutvec);
Chris@16:       std::transform(invec, invec + *plen, outvec, outvec, *op_ptr);
Chris@16:     }
Chris@16:   };
Chris@16: 
Chris@16:   template<typename Op, typename T> Op* user_op<Op, T>::op_ptr = 0;
Chris@16: 
Chris@16: } // end namespace detail
Chris@16: 
Chris@16: } } // end namespace boost::mpi
Chris@16: 
Chris@16: #endif // BOOST_MPI_GET_MPI_OP_HPP