reduce_direct.hpp#

See Public API for a list of names and headers that are part of the public HPX API.

namespace hpx

namespace lcos

Functions

template<typename Action, typename ReduceOp, typename ArgN, ...> hpx::future< decltype(Action(hpx::id_type, ArgN,...))> reduce (std::vector< hpx::id_type > const &ids, ReduceOp &&reduce_op, ArgN argN,...)

Perform a distributed reduction operation.

The function hpx::lcos::reduce performs a distributed reduction operation over results returned from action invocations on a given set of global identifiers. The action can be either a plain action (in which case the global identifiers have to refer to localities) or a component action (in which case the global identifiers have to refer to instances of a component type which exposes the action.

Parameters

ids – [in] A list of global identifiers identifying the target objects for which the given action will be invoked.
reduce_op – [in] A binary function expecting two results as returned from the action invocations. The function (or function object) is expected to return the result of the reduction operation performed on its arguments.
argN – [in] Any number of arbitrary arguments (passed by by const reference) which will be forwarded to the action invocation.

Returns

This function returns a future representing the result of the overall reduction operation.

template<typename Action, typename ReduceOp, typename ArgN, ...> hpx::future< decltype(Action(hpx::id_type, ArgN,..., std::size_t))> reduce_with_index (std::vector< hpx::id_type > const &ids, ReduceOp &&reduce_op, ArgN argN,...)

Perform a distributed reduction operation.

The function hpx::lcos::reduce_with_index performs a distributed reduction operation over results returned from action invocations on a given set of global identifiers. The action can be either plain action (in which case the global identifiers have to refer to localities) or a component action (in which case the global identifiers have to refer to instances of a component type which exposes the action.

The function passes the index of the global identifier in the given list of identifiers as the last argument to the action.

Parameters

ids – [in] A list of global identifiers identifying the target objects for which the given action will be invoked.
reduce_op – [in] A binary function expecting two results as returned from the action invocations. The function (or function object) is expected to return the result of the reduction operation performed on its arguments.
argN – [in] Any number of arbitrary arguments (passed by by const reference) which will be forwarded to the action invocation.

Returns

This function returns a future representing the result of the overall reduction operation.