CL-transform_reduce

Functions
template<typename InputIterator , typename UnaryFunction , typename T , typename BinaryFunction >
T	bolt::cl::transform_reduce (control &ctl, InputIterator first, InputIterator last, UnaryFunction transform_op, T init, BinaryFunction reduce_op, const std::string &user_code="")
	transform_reduce fuses transform and reduce operations together, increasing performance by reducing memory passes.
template<typename InputIterator , typename UnaryFunction , typename T , typename BinaryFunction >
T	bolt::cl::transform_reduce (InputIterator first, InputIterator last, UnaryFunction transform_op, T init, BinaryFunction reduce_op, const std::string &user_code="")

Detailed Description

Function Documentation

template<typename InputIterator , typename UnaryFunction , typename T , typename BinaryFunction >

T bolt::cl::transform_reduce	(	control &	ctl,
		InputIterator	first,
		InputIterator	last,
		UnaryFunction	transform_op,
		T	init,
		BinaryFunction	reduce_op,
		const std::string &	user_code = ""
	)

transform_reduce fuses transform and reduce operations together, increasing performance by reducing memory passes.

Logically, a transform operation is performed over the input sequence using the unary function and stored into a temporary sequence; then, a reduction operation is applied using the binary function to return a single value.

Parameters

ctl	Optional Control structure to control command-queue, debug, tuning, etc.See bolt::cl::control.
first	The beginning of the input sequence.
last	The end of the input sequence.
transform_op	A unary tranformation operation.
init	The initial value for the accumulator.
reduce_op	The binary operation used to combine two values. By default, the binary operation is plus<>().
user_code	Optional OpenCL™ code to be passed to the OpenCL compiler. The cl_code is inserted first in the generated code, before the cl_code trait.

Returns

The result of the combined transform and reduction.

Template Parameters

T	The type of the result.
InputIterator	is a model of an InputIterator. and InputIterator's value_type is convertible to BinaryFunction's first_argument_type.
UnaryFunction	is a model of Unary Function. and UnaryFunction's result_type is convertible to InputIterator's value_type.
BinaryFunction	is a model of Binary Function. and BinaryFunction's result_type is convertible to InputIterator's value_type.

#include <bolt/cl/transform_reduce.h>
#include <bolt/cl/functional.h>

int input[10] = {-5,  0,  2,  3,  2,  4, -2,  1,  2,  3};
int output;

bolt::cl::transform_reduce( input, input + 10, bolt::cl::square<int>(), 0, bolt::cl::plus<int>() );

// output is 76

See Also

http://www.sgi.com/tech/stl/InputIterator.html

http://www.sgi.com/tech/stl/OutputIterator.html

http://www.sgi.com/tech/stl/UnaryFunction.html

http://www.sgi.com/tech/stl/BinaryFunction.html