kamping::internal::mpi_operation_traits< Op, Datatype > Struct Template Reference

Type trait for checking whether a functor is a builtin MPI reduction operation and query corresponding MPI_Op. More...

#include <mpi_ops.hpp>

Static Public Member Functions
static MPI_Op	op ()
	get the MPI_Op for a builtin type

Static Public Attributes
static constexpr bool	is_builtin
	true if the operation defined by Op is a builtin MPI operation for the type Datatype
static constexpr T	identity
	The identity of this operation applied on this datatype.

Detailed Description

template<typename Op, typename Datatype>
struct kamping::internal::mpi_operation_traits< Op, Datatype >

Type trait for checking whether a functor is a builtin MPI reduction operation and query corresponding MPI_Op.

Example:

is_builtin_mpi_op<kamping::ops::plus<>, int>::value // true
is_builtin_mpi_op<kamping::ops::plus<>, int>::op()  // MPI_SUM
is_builtin_mpi_op<std::plus<>, int>::value          // true
is_builtin_mpi_op<std::plus<>, int>::op()           // MPI_SUM
is_builtin_mpi_op<std::minus<>, int>::value         // false
//is_builtin_mpi_op<std::minus<>, int>::op()        // error: fails to compile because op is not defined

Template Parameters

Op	type of the operation
Datatype	type to apply the operation to

Member Function Documentation

op()

template<typename Op , typename Datatype >

static MPI_Op kamping::internal::mpi_operation_traits< Op, Datatype >::op ( )

static

get the MPI_Op for a builtin type

This member is only defined if value is true. It can then be used to query the predefined constant of type MPI_OP matching the functor defined by type Op, e.g. returns MPI_SUM if Op is kamping::ops::plus<>.

Returns

the builtin MPI_Op constant

Member Data Documentation

identity

template<typename Op , typename Datatype >

constexpr T kamping::internal::mpi_operation_traits< Op, Datatype >::identity

staticconstexpr

The identity of this operation applied on this datatype.

The identity of a {value, operation} pair is the value for which the following two equation holds:

• identity operation value = value
• value operation identity = value

is_builtin

template<typename Op , typename Datatype >

constexpr bool kamping::internal::mpi_operation_traits< Op, Datatype >::is_builtin

staticconstexpr

true if the operation defined by Op is a builtin MPI operation for the type Datatype

Note that this is only true if the MPI_Datatype corresponding to the C++ datatype Datatype supports the operation according to the standard. If MPI supports the operation for this type, then this is true for functors defined in kamping::ops and there corresponding type-aliased equivalents in the standard library.

---

The documentation for this struct was generated from the following file:

• include/kamping/mpi_ops.hpp