cub::TransformInputIterator< ValueType, ConversionOp, InputIteratorT, OffsetT > Class Template Reference

A random-access input wrapper for transforming dereferenced values. More...

Detailed Description

template<typename ValueType, typename ConversionOp, typename InputIteratorT, typename OffsetT = ptrdiff_t>
class cub::TransformInputIterator< ValueType, ConversionOp, InputIteratorT, OffsetT >

A random-access input wrapper for transforming dereferenced values.

Overview

• TransformInputIteratorTwraps a unary conversion functor of type ConversionOp and a random-access input iterator of type InputIteratorT, using the former to produce references of type ValueType from the latter.
• Can be used with any data type.
• Can be constructed, manipulated, and exchanged within and between host and device functions. Wrapped host memory can only be dereferenced on the host, and wrapped device memory can only be dereferenced on the device.
• Compatible with Thrust API v1.7 or newer.

Snippet

The code snippet below illustrates the use of TransformInputIteratorTto dereference an array of integers, tripling the values and converting them to doubles.

#include <cub/cub.cuh>   // or equivalently <cub/iterator/transform_input_iterator.cuh>

// Functor for tripling integer values and converting to doubles
struct TripleDoubler
{
    __host__ __device__ __forceinline__
    double operator()(const int &a) const {
        return double(a * 3);
    }
};

// Declare, allocate, and initialize a device array
int *d_in;                   // e.g., [8, 6, 7, 5, 3, 0, 9]
TripleDoubler conversion_op;

// Create an iterator wrapper
cub::TransformInputIterator<double, TripleDoubler, int*> itr(d_in, conversion_op);

// Within device code:
printf("%f\n", itr[0]);  // 24.0
printf("%f\n", itr[1]);  // 18.0
printf("%f\n", itr[6]);  // 27.0

Template Parameters

ValueType	The value type of this iterator
ConversionOp	Unary functor type for mapping objects of type InputType to type ValueType. Must have member ValueType operator()(const InputType &datum).
InputIteratorT	The type of the wrapped input iterator
OffsetT	The difference type of this iterator (Default: ptrdiff_t)

Definition at line 117 of file transform_input_iterator.cuh.

Public Types
typedef TransformInputIterator	self_type
	My own type.
typedef OffsetT	difference_type
	Type to express the result of subtracting one iterator from another.
typedef ValueType	value_type
	The type of the element the iterator can point to.
typedef ValueType *	pointer
	The type of a pointer to an element the iterator can point to.
typedef ValueType	reference
	The type of a reference to an element the iterator can point to.
typedef std::random_access_iterator_tag	iterator_category
	The iterator category.

Public Member Functions
__host__ __device__ __forceinline__	TransformInputIterator (InputIteratorT input_itr, ConversionOp conversion_op)
	Constructor. More...
__host__ __device__ __forceinline__ self_type	operator++ (int)
	Postfix increment.
__host__ __device__ __forceinline__ self_type	operator++ ()
	Prefix increment.
__host__ __device__ __forceinline__ reference	operator * () const
	Indirection.
template<typename Distance >
__host__ __device__ __forceinline__ self_type	operator+ (Distance n) const
	Addition.
template<typename Distance >
__host__ __device__ __forceinline__ self_type &	operator+= (Distance n)
	Addition assignment.
template<typename Distance >
__host__ __device__ __forceinline__ self_type	operator- (Distance n) const
	Subtraction.
template<typename Distance >
__host__ __device__ __forceinline__ self_type &	operator-= (Distance n)
	Subtraction assignment.
__host__ __device__ __forceinline__ difference_type	operator- (self_type other) const
	Distance.
template<typename Distance >
__host__ __device__ __forceinline__ reference	operator[] (Distance n) const
	Array subscript.
__host__ __device__ __forceinline__ pointer	operator-> ()
	Structure dereference.
__host__ __device__ __forceinline__ bool	operator== (const self_type &rhs)
	Equal to.
__host__ __device__ __forceinline__ bool	operator!= (const self_type &rhs)
	Not equal to.

Private Attributes
ConversionOp	conversion_op
InputIteratorT	input_itr

Friends
std::ostream &	operator<< (std::ostream &os, const self_type &itr)
	ostream operator

Constructor & Destructor Documentation

TransformInputIterator()

template<typename ValueType, typename ConversionOp, typename InputIteratorT, typename OffsetT = ptrdiff_t>

__host__ __device__ __forceinline__ cub::TransformInputIterator< ValueType, ConversionOp, InputIteratorT, OffsetT >::TransformInputIterator ( InputIteratorT  input_itr, ConversionOp  conversion_op  )

inline

Constructor.

Parameters

input_itr	Input iterator to wrap
conversion_op	Conversion functor to wrap

Definition at line 148 of file transform_input_iterator.cuh.

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

• openfpm_data/src/util/cuda/cub_old/iterator/transform_input_iterator.cuh