tf::GuidedPartitioner< C > Class Template Reference

class to create a guided partitioner for scheduling parallel algorithms More...

#include <taskflow/algorithm/partitioner.hpp>

Inheritance diagram for tf::GuidedPartitioner< C >:

Collaboration diagram for tf::GuidedPartitioner< C >:

Public Member Functions
	GuidedPartitioner ()=default
	default constructor
	GuidedPartitioner (size_t sz)
	construct a guided partitioner with the given chunk size
	GuidedPartitioner (size_t sz, C &&closure)
	construct a guided partitioner with the given chunk size and the closure
Public Member Functions inherited from tf::PartitionerBase< DefaultClosureWrapper >
	PartitionerBase ()=default
	default constructor
	PartitionerBase (size_t chunk_size)
	construct a partitioner with the given chunk size
	PartitionerBase (size_t chunk_size, DefaultClosureWrapper &&closure_wrapper)
	construct a partitioner with the given chunk size and closure wrapper
size_t	chunk_size () const
	query the chunk size of this partitioner
void	chunk_size (size_t cz)
	update the chunk size of this partitioner
const DefaultClosureWrapper &	closure_wrapper () const
	acquire an immutable access to the closure wrapper object
DefaultClosureWrapper &	closure_wrapper ()
	acquire a mutable access to the closure wrapper object
void	closure_wrapper (F &&fn)
	modify the closure wrapper object
TF_FORCE_INLINE decltype(auto)	operator() (F &&callable)
	wraps the given callable with the associated closure wrapper

Static Public Member Functions
static constexpr PartitionerType	type ()
	queries the partition type (dynamic)

Additional Inherited Members
Public Types inherited from tf::PartitionerBase< DefaultClosureWrapper >
using	closure_wrapper_type
	the closure type
Static Public Attributes inherited from tf::PartitionerBase< DefaultClosureWrapper >
static constexpr bool	is_default_wrapper_v
	indicating if the given closure wrapper is a default wrapper (i.e., empty)
Protected Attributes inherited from tf::PartitionerBase< DefaultClosureWrapper >
size_t	_chunk_size
	chunk size
DefaultClosureWrapper	_closure_wrapper
	closure wrapper

Detailed Description

template<typename C = DefaultClosureWrapper>
class tf::GuidedPartitioner< C >

class to create a guided partitioner for scheduling parallel algorithms

Template Parameters

C	closure wrapper type (default tf::DefaultClosureWrapper)

The size of a partition is proportional to the number of unassigned iterations divided by the number of workers, and the size will gradually decrease to the given chunk size. The last partition may be smaller than the chunk size.

In addition to partition size, the application can specify a closure wrapper for a guided partitioner. A closure wrapper allows the application to wrap a partitioned task (i.e., closure) with a custom function object that performs additional tasks. For example:

std::atomic<int> count = 0;
tf::Taskflow taskflow;
taskflow.for_each_index(0, 100, 1, 
  [](){                 
    printf("%d\n", i); 
  },
  tf::GuidedPartitioner(0, [](auto&& closure){
    // do something before invoking the partitioned task
    // ...
    
    // invoke the partitioned task
    closure();
 
    // do something else after invoking the partitioned task
    // ...
  }
);
executor.run(taskflow).wait();

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

• taskflow/algorithm/partitioner.hpp