unique_by_key_copy#

Overloads#

unique_by_key_copy(exec, keys_first, keys_last, values_first, keys_result, values_result)#

template<typename DerivedPolicy, typename InputIterator1, typename InputIterator2, typename OutputIterator1, typename OutputIterator2>
thrust::pair<OutputIterator1, OutputIterator2> thrust::unique_by_key_copy(
const thrust::detail::execution_policy_base<DerivedPolicy> &exec,
InputIterator1 keys_first,
InputIterator1 keys_last,
InputIterator2 values_first,
OutputIterator1 keys_result,
OutputIterator2 values_result,
)#

unique_by_key_copy is a generalization of unique_copy to key-value pairs. For each group of consecutive keys in the range [keys_first, keys_last) that are equal, unique_by_key_copy copies the first element of the group to a range beginning with keys_result and the corresponding values from the range [values_first, values_first + (keys_last - keys_first)) are copied to a range beginning with values_result.

This version of unique_by_key_copy uses operator== to test for equality and project1st to reduce values with equal keys.

The algorithm’s execution is parallelized as determined by exec.

The following code snippet demonstrates how to use unique_by_key_copy to compact a sequence of key/value pairs and with equal keys using the thrust::host execution policy for parallelization:

#include <thrust/unique.h>
#include <thrust/execution_policy.h>
...
const int N = 7;
int A[N] = {1, 3, 3, 3, 2, 2, 1}; // input keys
int B[N] = {9, 8, 7, 6, 5, 4, 3}; // input values
int C[N];                         // output keys
int D[N];                         // output values

thrust::pair<int*,int*> new_end;
new_end = thrust::unique_by_key_copy(thrust::host, A, A + N, B, C, D);

// The first four keys in C are now {1, 3, 2, 1} and new_end.first - C is 4.
// The first four values in D are now {9, 8, 5, 3} and new_end.second - D is 4.

See also

unique_copy

See also

unique_by_key

See also

reduce_by_key

Parameters:

  • exec – The execution policy to use for parallelization.

  • keys_first – The beginning of the input key range.

  • keys_last – The end of the input key range.

  • values_first – The beginning of the input value range.

  • keys_result – The beginning of the output key range.

  • values_result – The beginning of the output value range.

Template Parameters:

  • DerivedPolicy – The name of the derived execution policy.

  • InputIterator1 – is a model of Input Iterator,

  • InputIterator2 – is a model of Input Iterator,

  • OutputIterator1 – is a model of Output Iterator and and InputIterator1's value_type is convertible to OutputIterator1's value_type.

  • OutputIterator2 – is a model of Output Iterator and and InputIterator2's value_type is convertible to OutputIterator2's value_type.

Returns:

A pair of iterators at end of the ranges [keys_result, keys_result_last) and [values_result, values_result_last).

Pre:

The input ranges shall not overlap either output range.

unique_by_key_copy(keys_first, keys_last, values_first, keys_result, values_result)#

template<typename InputIterator1, typename InputIterator2, typename OutputIterator1, typename OutputIterator2>
thrust::pair<OutputIterator1, OutputIterator2> thrust::unique_by_key_copy(
InputIterator1 keys_first,
InputIterator1 keys_last,
InputIterator2 values_first,
OutputIterator1 keys_result,
OutputIterator2 values_result,
)#

unique_by_key_copy is a generalization of unique_copy to key-value pairs. For each group of consecutive keys in the range [keys_first, keys_last) that are equal, unique_by_key_copy copies the first element of the group to a range beginning with keys_result and the corresponding values from the range [values_first, values_first + (keys_last - keys_first)) are copied to a range beginning with values_result.

This version of unique_by_key_copy uses operator== to test for equality and project1st to reduce values with equal keys.

The following code snippet demonstrates how to use unique_by_key_copy to compact a sequence of key/value pairs and with equal keys.

#include <thrust/unique.h>
...
const int N = 7;
int A[N] = {1, 3, 3, 3, 2, 2, 1}; // input keys
int B[N] = {9, 8, 7, 6, 5, 4, 3}; // input values
int C[N];                         // output keys
int D[N];                         // output values

thrust::pair<int*,int*> new_end;
new_end = thrust::unique_by_key_copy(A, A + N, B, C, D);

// The first four keys in C are now {1, 3, 2, 1} and new_end.first - C is 4.
// The first four values in D are now {9, 8, 5, 3} and new_end.second - D is 4.

See also

unique_copy

See also

unique_by_key

See also

reduce_by_key

Parameters:

  • keys_first – The beginning of the input key range.

  • keys_last – The end of the input key range.

  • values_first – The beginning of the input value range.

  • keys_result – The beginning of the output key range.

  • values_result – The beginning of the output value range.

Template Parameters:

  • InputIterator1 – is a model of Input Iterator,

  • InputIterator2 – is a model of Input Iterator,

  • OutputIterator1 – is a model of Output Iterator and and InputIterator1's value_type is convertible to OutputIterator1's value_type.

  • OutputIterator2 – is a model of Output Iterator and and InputIterator2's value_type is convertible to OutputIterator2's value_type.

Returns:

A pair of iterators at end of the ranges [keys_result, keys_result_last) and [values_result, values_result_last).

Pre:

The input ranges shall not overlap either output range.

unique_by_key_copy(exec, keys_first, keys_last, values_first, keys_result, values_result, binary_pred)#

template<typename DerivedPolicy, typename InputIterator1, typename InputIterator2, typename OutputIterator1, typename OutputIterator2, typename BinaryPredicate>
thrust::pair<OutputIterator1, OutputIterator2> thrust::unique_by_key_copy(
const thrust::detail::execution_policy_base<DerivedPolicy> &exec,
InputIterator1 keys_first,
InputIterator1 keys_last,
InputIterator2 values_first,
OutputIterator1 keys_result,
OutputIterator2 values_result,
BinaryPredicate binary_pred,
)#

unique_by_key_copy is a generalization of unique_copy to key-value pairs. For each group of consecutive keys in the range [keys_first, keys_last) that are equal, unique_by_key_copy copies the first element of the group to a range beginning with keys_result and the corresponding values from the range [values_first, values_first + (keys_last - keys_first)) are copied to a range beginning with values_result.

This version of unique_by_key_copy uses the function object binary_pred to test for equality and project1st to reduce values with equal keys.

The algorithm’s execution is parallelized as determined by exec.

The following code snippet demonstrates how to use unique_by_key_copy to compact a sequence of key/value pairs and with equal keys using the thrust::host execution policy for parallelization:

#include <thrust/unique.h>
#include <thrust/execution_policy.h>
...
const int N = 7;
int A[N] = {1, 3, 3, 3, 2, 2, 1}; // input keys
int B[N] = {9, 8, 7, 6, 5, 4, 3}; // input values
int C[N];                         // output keys
int D[N];                         // output values

thrust::pair<int*,int*> new_end;
::cuda::std::equal_to<int> binary_pred;
new_end = thrust::unique_by_key_copy(thrust::host, A, A + N, B, C, D, binary_pred);

// The first four keys in C are now {1, 3, 2, 1} and new_end.first - C is 4.
// The first four values in D are now {9, 8, 5, 3} and new_end.second - D is 4.

See also

unique_copy

See also

unique_by_key

See also

reduce_by_key

Parameters:

  • exec – The execution policy to use for parallelization.

  • keys_first – The beginning of the input key range.

  • keys_last – The end of the input key range.

  • values_first – The beginning of the input value range.

  • keys_result – The beginning of the output key range.

  • values_result – The beginning of the output value range.

  • binary_pred – The binary predicate used to determine equality.

Template Parameters:

  • DerivedPolicy – The name of the derived execution policy.

  • InputIterator1 – is a model of Input Iterator,

  • InputIterator2 – is a model of Input Iterator,

  • OutputIterator1 – is a model of Output Iterator and and InputIterator1's value_type is convertible to OutputIterator1's value_type.

  • OutputIterator2 – is a model of Output Iterator and and InputIterator2's value_type is convertible to OutputIterator2's value_type.

  • BinaryPredicate – is a model of Binary Predicate.

Returns:

A pair of iterators at end of the ranges [keys_result, keys_result_last) and [values_result, values_result_last).

Pre:

The input ranges shall not overlap either output range.

unique_by_key_copy(keys_first, keys_last, values_first, keys_result, values_result, binary_pred)#

template<typename InputIterator1, typename InputIterator2, typename OutputIterator1, typename OutputIterator2, typename BinaryPredicate>
thrust::pair<OutputIterator1, OutputIterator2> thrust::unique_by_key_copy(
InputIterator1 keys_first,
InputIterator1 keys_last,
InputIterator2 values_first,
OutputIterator1 keys_result,
OutputIterator2 values_result,
BinaryPredicate binary_pred,
)#

unique_by_key_copy is a generalization of unique_copy to key-value pairs. For each group of consecutive keys in the range [keys_first, keys_last) that are equal, unique_by_key_copy copies the first element of the group to a range beginning with keys_result and the corresponding values from the range [values_first, values_first + (keys_last - keys_first)) are copied to a range beginning with values_result.

This version of unique_by_key_copy uses the function object binary_pred to test for equality and project1st to reduce values with equal keys.

The following code snippet demonstrates how to use unique_by_key_copy to compact a sequence of key/value pairs and with equal keys.

#include <thrust/unique.h>
...
const int N = 7;
int A[N] = {1, 3, 3, 3, 2, 2, 1}; // input keys
int B[N] = {9, 8, 7, 6, 5, 4, 3}; // input values
int C[N];                         // output keys
int D[N];                         // output values

thrust::pair<int*,int*> new_end;
::cuda::std::equal_to<int> binary_pred;
new_end = thrust::unique_by_key_copy(A, A + N, B, C, D, binary_pred);

// The first four keys in C are now {1, 3, 2, 1} and new_end.first - C is 4.
// The first four values in D are now {9, 8, 5, 3} and new_end.second - D is 4.

See also

unique_copy

See also

unique_by_key

See also

reduce_by_key

Parameters:

  • keys_first – The beginning of the input key range.

  • keys_last – The end of the input key range.

  • values_first – The beginning of the input value range.

  • keys_result – The beginning of the output key range.

  • values_result – The beginning of the output value range.

  • binary_pred – The binary predicate used to determine equality.

Template Parameters:

  • InputIterator1 – is a model of Input Iterator,

  • InputIterator2 – is a model of Input Iterator,

  • OutputIterator1 – is a model of Output Iterator and and InputIterator1's value_type is convertible to OutputIterator1's value_type.

  • OutputIterator2 – is a model of Output Iterator and and InputIterator2's value_type is convertible to OutputIterator2's value_type.

  • BinaryPredicate – is a model of Binary Predicate.

Returns:

A pair of iterators at end of the ranges [keys_result, keys_result_last) and [values_result, values_result_last).

Pre:

The input ranges shall not overlap either output range.