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thrust
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Functions | |
| template<typename InputIterator , typename OutputIterator , typename Predicate > | |
| OutputIterator | thrust::copy_if (InputIterator first, InputIterator last, OutputIterator result, Predicate pred) |
| template<typename InputIterator1 , typename InputIterator2 , typename OutputIterator , typename Predicate > | |
| OutputIterator | thrust::copy_if (InputIterator1 first, InputIterator1 last, InputIterator2 stencil, OutputIterator result, Predicate pred) |
| template<typename ForwardIterator , typename T > | |
| ForwardIterator | thrust::remove (ForwardIterator first, ForwardIterator last, const T &value) |
| template<typename InputIterator , typename OutputIterator , typename T > | |
| OutputIterator | thrust::remove_copy (InputIterator first, InputIterator last, OutputIterator result, const T &value) |
| template<typename ForwardIterator , typename Predicate > | |
| ForwardIterator | thrust::remove_if (ForwardIterator first, ForwardIterator last, Predicate pred) |
| template<typename InputIterator , typename OutputIterator , typename Predicate > | |
| OutputIterator | thrust::remove_copy_if (InputIterator first, InputIterator last, OutputIterator result, Predicate pred) |
| template<typename ForwardIterator , typename InputIterator , typename Predicate > | |
| ForwardIterator | thrust::remove_if (ForwardIterator first, ForwardIterator last, InputIterator stencil, Predicate pred) |
| template<typename InputIterator1 , typename InputIterator2 , typename OutputIterator , typename Predicate > | |
| OutputIterator | thrust::remove_copy_if (InputIterator1 first, InputIterator1 last, InputIterator2 stencil, OutputIterator result, Predicate pred) |
| template<typename ForwardIterator > | |
| ForwardIterator | thrust::unique (ForwardIterator first, ForwardIterator last) |
| template<typename ForwardIterator , typename BinaryPredicate > | |
| ForwardIterator | thrust::unique (ForwardIterator first, ForwardIterator last, BinaryPredicate binary_pred) |
| template<typename InputIterator , typename OutputIterator > | |
| OutputIterator | thrust::unique_copy (InputIterator first, InputIterator last, OutputIterator output) |
| template<typename InputIterator , typename OutputIterator , typename BinaryPredicate > | |
| OutputIterator | thrust::unique_copy (InputIterator first, InputIterator last, OutputIterator output, BinaryPredicate binary_pred) |
| template<typename ForwardIterator1 , typename ForwardIterator2 > | |
| thrust::pair< ForwardIterator1, ForwardIterator2 > | thrust::unique_by_key (ForwardIterator1 keys_first, ForwardIterator1 keys_last, ForwardIterator2 values_first) |
| template<typename ForwardIterator1 , typename ForwardIterator2 , typename BinaryPredicate > | |
| thrust::pair< ForwardIterator1, ForwardIterator2 > | thrust::unique_by_key (ForwardIterator1 keys_first, ForwardIterator1 keys_last, ForwardIterator2 values_first, BinaryPredicate binary_pred) |
| 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_output, OutputIterator2 values_output) |
| 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_output, OutputIterator2 values_output, BinaryPredicate binary_pred) |
| OutputIterator thrust::copy_if | ( | InputIterator | first, |
| InputIterator | last, | ||
| OutputIterator | result, | ||
| Predicate | pred | ||
| ) |
This version of copy_if copies elements from the range [first,last) to a range beginning at \ presult, except that any element which causes pred to be pred to be false is not copied.
More precisely, for every integer n such that 0 <= n < last-first, copy_if performs the assignment *result = *(first+n) and result is advanced one position if pred(*(first+n)). Otherwise, no assignment occurs and result is not advanced.
| first | The beginning of the sequence from which to copy. |
| last | The end of the sequence from which to copy. |
| result | The beginning of the sequence into which to copy. |
| pred | The predicate to test on every value of the range [first, last). |
result + n, where n is equal to the number of times pred evaluated to true in the range [first, last).| InputIterator | is a model of Input Iterator, and InputIterator's value_type is convertible to Predicate's argument_type. |
| OutputIterator | is a model of Output Iterator. |
| Predicate | is a model of Predicate. |
The following code snippet demonstrates how to use copy_if to perform stream compaction to copy even numbers to an output range.
#include <thrust/copy.h> ... struct is_even { __host__ __device__ bool operator()(const int x) { return (x % 2) == 0; } }; ... const int N = 6; int V[N] = {-2, 0, -1, 0, 1, 2}; int result[4]; thrust::copy_if(V, V + N, result, is_even()); // V remains {-2, 0, -1, 0, 1, 2} // result is now {-2, 0, 0, 2}
remove_copy_if | OutputIterator thrust::copy_if | ( | InputIterator1 | first, |
| InputIterator1 | last, | ||
| InputIterator2 | stencil, | ||
| OutputIterator | result, | ||
| Predicate | pred | ||
| ) |
This version of copy_if copies elements from the range [first,last) to a range beginning at result, except that any element whose corresponding stencil element causes pred to be false is not copied.
More precisely, for every integer n such that 0 <= n < last-first, copy_if performs the assignment *result = *(first+n) and result is advanced one position if pred(*(stencil+n)). Otherwise, no assignment occurs and result is not advanced.
| first | The beginning of the sequence from which to copy. |
| last | The end of the sequence from which to copy. |
| stencil | The beginning of the stencil sequence. |
| result | The beginning of the sequence into which to copy. |
| pred | The predicate to test on every value of the range [stencil, stencil + (last-first)). |
result + n, where n is equal to the number of times pred evaluated to true in the range [stencil, stencil + (last-first)).| InputIterator1 | is a model of Input Iterator. |
| InputIterator2 | is a model of Input Iterator, and InputIterator2's value_type is convertible to Predicate's argument_type. |
| OutputIterator | is a model of Output Iterator. |
| Predicate | is a model of Predicate. |
The following code snippet demonstrates how to use copy_if to perform stream compaction to copy numbers to an output range when corresponding stencil elements are even:
#include <thrust/copy.h> ... struct is_even { __host__ __device__ bool operator()(const int x) { return (x % 2) == 0; } }; ... int N = 6; int data[N] = { 0, 1, 2, 3, 4, 5}; int stencil[N] = {-2, 0, -1, 0, 1, 2}; int result[4]; thrust::copy_if(data, data + N, stencil, result, is_even()); // data remains = { 0, 1, 2, 3, 4, 5}; // stencil remains = {-2, 0, -1, 0, 1, 2}; // result is now { 0, 1, 3, 5}
remove_copy_if | ForwardIterator thrust::remove | ( | ForwardIterator | first, |
| ForwardIterator | last, | ||
| const T & | value | ||
| ) |
remove removes from the range [first, last) all elements that are equal to value. That is, remove returns an iterator new_last such that the range [first, new_last) contains no elements equal to value. The iterators in the range [new_first,last) are all still dereferenceable, but the elements that they point to are unspecified. remove is stable, meaning that the relative order of elements that are not equal to value is unchanged.
| first | The beginning of the range of interest. |
| last | The end of the range of interest. |
| value | The value to remove from the range [first, last). Elements which are equal to value are removed from the sequence. |
ForwardIterator pointing to the end of the resulting range of elements which are not equal to value.| ForwardIterator | is a model of Forward Iterator, and ForwardIterator is mutable. |
| T | is a model of Equality Comparable, and objects of type T can be compared for equality with objects of ForwardIterator's value_type. |
The following code snippet demonstrates how to use remove to remove a number of interest from a range.
#include <thrust/remove.h> ... const int N = 6; int A[N] = {3, 1, 4, 1, 5, 9}; int *new_end = thrust::remove(A, A + N, 1); // The first four values of A are now {3, 4, 5, 9} // Values beyond new_end are unspecified
remove does not destroy any iterators, and does not change the distance between first and last. (There's no way that it could do anything of the sort.) So, for example, if V is a device_vector, remove(V.begin(), V.end(), 0) does not change V.size(): V will contain just as many elements as it did before. remove returns an iterator that points to the end of the resulting range after elements have been removed from it; it follows that the elements after that iterator are of no interest, and may be discarded. If you are removing elements from a Sequence, you may simply erase them. That is, a reasonable way of removing elements from a Sequence is S.erase(remove(S.begin(), S.end(), x), S.end()).| OutputIterator thrust::remove_copy | ( | InputIterator | first, |
| InputIterator | last, | ||
| OutputIterator | result, | ||
| const T & | value | ||
| ) |
remove_copy copies elements that are not equal to value from the range [first, last) to a range beginning at result. The return value is the end of the resulting range. This operation is stable, meaning that the relative order of the elements that are copied is the same as in the range [first, last).
| first | The beginning of the range of interest. |
| last | The end of the range of interest. |
| result | The resulting range is copied to the sequence beginning at this location. |
| value | The value to omit from the copied range. |
value.| InputIterator | is a model of Input Iterator, and InputIterator's value_type is convertible to a type in OutputIterator's set of value_types. |
| OutputIterator | is a model of Output Iterator. |
| T | is a model of Equality Comparable, and objects of type T can be compared for equality with objects of InputIterator's value_type. |
The following code snippet demonstrates how to use remove_copy to copy a sequence of numbers to an output range while omitting a value of interest.
#include <thrust/remove.h> ... const int N = 6; int V[N] = {-2, 0, -1, 0, 1, 2}; int result[N-2]; thrust::remove_copy(V, V + N, result, 0); // V remains {-2, 0, -1, 0, 1, 2} // result is now {-2, -1, 1, 2}
| OutputIterator thrust::remove_copy_if | ( | InputIterator | first, |
| InputIterator | last, | ||
| OutputIterator | result, | ||
| Predicate | pred | ||
| ) |
remove_copy_if copies elements from the range [first,last) to a range beginning at result, except that elements for which pred is true are not copied. The return value is the end of the resulting range. This operation is stable, meaning that the relative order of the elements that are copied is the same as the range [first,last).
| first | The beginning of the range of interest. |
| last | The end of the range of interest. |
| result | The resulting range is copied to the sequence beginning at this location. |
| pred | A predicate to evaluate for each element of the range [first,last). Elements for which pred evaluates to false are not copied to the resulting sequence. |
| InputIterator | is a model of Input Iterator, InputIterator's value_type is convertible to a type in OutputIterator's set of value_types, and InputIterator's value_type is convertible to Predicate's argument_type. |
| OutputIterator | is a model of Output Iterator. |
| Predicate | is a model of Predicate. |
The following code snippet demonstrates how to use remove_copy_if to copy a sequence of numbers to an output range while omitting even numbers.
#include <thrust/remove.h> ... struct is_even { __host__ __device__ bool operator()(const int x) { return (x % 2) == 0; } }; ... const int N = 6; int V[N] = {-2, 0, -1, 0, 1, 2}; int result[2]; thrust::remove_copy_if(V, V + N, result, is_even()); // V remains {-2, 0, -1, 0, 1, 2} // result is now {-1, 1}
| OutputIterator thrust::remove_copy_if | ( | InputIterator1 | first, |
| InputIterator1 | last, | ||
| InputIterator2 | stencil, | ||
| OutputIterator | result, | ||
| Predicate | pred | ||
| ) |
remove_copy_if copies elements from the range [first,last) to a range beginning at result, except that elements for which pred of the corresponding stencil value is true are not copied. The return value is the end of the resulting range. This operation is stable, meaning that the relative order of the elements that are copied is the same as the range [first,last).
| first | The beginning of the range of interest. |
| last | The end of the range of interest. |
| stencil | The beginning of the stencil sequence. |
| result | The resulting range is copied to the sequence beginning at this location. |
| pred | A predicate to evaluate for each element of the range [first,last). Elements for which pred evaluates to false are not copied to the resulting sequence. |
| InputIterator1 | is a model of Input Iterator, InputIterator1's value_type is convertible to a type in OutputIterator's set of value_types. |
| InputIterator2 | is a model of Input Iterator, and InputIterator2's value_type is convertible to Predicate's argument_type. |
| OutputIterator | is a model of Output Iterator. |
| Predicate | is a model of Predicate. |
The following code snippet demonstrates how to use remove_copy_if to copy a sequence of numbers to an output range while omitting specific elements.
#include <thrust/remove.h> ... const int N = 6; int V[N] = {-2, 0, -1, 0, 1, 2}; int S[N] = { 1, 1, 0, 1, 0, 1}; int result[2]; thrust::remove_copy_if(V, V + N, S, result, thrust::identity<int>()); // V remains {-2, 0, -1, 0, 1, 2} // result is now {-1, 1}
| ForwardIterator thrust::remove_if | ( | ForwardIterator | first, |
| ForwardIterator | last, | ||
| Predicate | pred | ||
| ) |
remove_if removes from the range [first, last) every element x such that pred(x) is true. That is, remove_if returns an iterator new_last such that the range [first,new_last) contains no elements for which pred is true. The iterators in the range [new_last,last) are all still dereferenceable, but the elements that they point to are unspecified. remove_if is stable, meaning that the relative order of elements that are not removed is unchanged.
| first | The beginning of the range of interest. |
| last | The end of the range of interest. |
| pred | A predicate to evaluate for each element of the range [first,last). Elements for which pred evaluates to false are removed from the sequence. |
pred evaluated to true.| ForwardIterator | is a model of Forward Iterator, ForwardIterator is mutable, and ForwardIterator's value_type is convertible to Predicate's argument_type. |
| Predicate | is a model of Predicate. |
The following code snippet demonstrates how to use remove_if to remove all even numbers from an array of integers.
#include <thrust/remove.h> ... struct is_even { __host__ __device__ bool operator()(const int x) { return (x % 2) == 0; } }; ... const int N = 6; int A[N] = {1, 4, 2, 8, 5, 7}; int *new_end = thrust::remove_if(A, A + N, is_even()); // The first three values of A are now {1, 5, 7} // Values beyond new_end are unspecified
remove_if does not destroy any iterators, and does not change the distance between first and last. (There's no way that it could do anything of the sort.) So, for example, if V is a device_vector, remove_if(V.begin(), V.end(), pred) does not change V.size(): V will contain just as many elements as it did before. remove_if returns an iterator that points to the end of the resulting range after elements have been removed from it; it follows that the elements after that iterator are of no interest, and may be discarded. If you are removing elements from a Sequence, you may simply erase them. That is, a reasonable way of removing elements from a Sequence is S.erase(remove_if(S.begin(), S.end(), pred), S.end()).| ForwardIterator thrust::remove_if | ( | ForwardIterator | first, |
| ForwardIterator | last, | ||
| InputIterator | stencil, | ||
| Predicate | pred | ||
| ) |
remove_if removes from the range [first, last) every element x such that pred(x) is true. That is, remove_if returns an iterator new_last such that the range [first, new_last) contains no elements for which pred of the corresponding stencil value is true. The iterators in the range [new_last,last) are all still dereferenceable, but the elements that they point to are unspecified. remove_if is stable, meaning that the relative order of elements that are not removed is unchanged.
| first | The beginning of the range of interest. |
| last | The end of the range of interest. |
| stencil | The beginning of the stencil sequence. |
| pred | A predicate to evaluate for each element of the range [stencil, stencil + (last - first)). Elements for which pred evaluates to false are removed from the sequence [first, last) |
pred evaluated to true.| ForwardIterator | is a model of Forward Iterator and ForwardIterator is mutable. |
| InputIterator | is a model of Input Iterator, and InputIterator's value_type is convertible to Predicate's argument_type. |
| Predicate | is a model of Predicate. |
The following code snippet demonstrates how to use remove_if to remove specific elements from an array of integers.
#include <thrust/remove.h> ... const int N = 6; int A[N] = {1, 4, 2, 8, 5, 7}; int S[N] = {0, 1, 1, 1, 0, 0}; int *new_end = thrust::remove(A, A + N, S, thrust::identity<int>()); // The first three values of A are now {1, 5, 7} // Values beyond new_end are unspecified
[first, last) is not permitted to overlap with the range [stencil, stencil + (last - first)).| ForwardIterator thrust::unique | ( | ForwardIterator | first, |
| ForwardIterator | last | ||
| ) |
For each group of consecutive elements in the range [first, last) with the same value, unique removes all but the first element of the group. The return value is an iterator new_last such that no two consecutive elements in the range [first, new_last) are equal. The iterators in the range [new_last, last) are all still dereferenceable, but the elements that they point to are unspecified. unique is stable, meaning that the relative order of elements that are not removed is unchanged.
This version of unique uses operator== to test for equality.
| first | The beginning of the input range. |
| last | The end of the input range. |
[first, new_last).| ForwardIterator | is a model of Forward Iterator, and ForwardIterator is mutable, and ForwardIterator's value_type is a model of Equality Comparable. |
The following code snippet demonstrates how to use unique to compact a sequence of numbers to remove consecutive duplicates.
#include <thrust/unique.h> ... const int N = 7; int A[N] = {1, 3, 3, 3, 2, 2, 1}; int *new_end = thrust::unique(A, A + N); // The first four values of A are now {1, 3, 2, 1} // Values beyond new_end are unspecified.
| ForwardIterator thrust::unique | ( | ForwardIterator | first, |
| ForwardIterator | last, | ||
| BinaryPredicate | binary_pred | ||
| ) |
For each group of consecutive elements in the range [first, last) with the same value, unique removes all but the first element of the group. The return value is an iterator new_last such that no two consecutive elements in the range [first, new_last) are equal. The iterators in the range [new_last, last) are all still dereferenceable, but the elements that they point to are unspecified. unique is stable, meaning that the relative order of elements that are not removed is unchanged.
This version of unique uses the function object binary_pred to test for equality.
| first | The beginning of the input range. |
| last | The end of the input range. |
| binary_pred | The binary predicate used to determine equality. |
[first, new_last)| ForwardIterator | is a model of Forward Iterator, and ForwardIterator is mutable, and ForwardIterator's value_type is convertible to BinaryPredicate's first_argument_type and to BinaryPredicate's second_argument_type. |
| BinaryPredicate | is a model of Binary Predicate. |
The following code snippet demonstrates how to use unique to compact a sequence of numbers to remove consecutive duplicates.
#include <thrust/unique.h> ... const int N = 7; int A[N] = {1, 3, 3, 3, 2, 2, 1}; int *new_end = thrust::unique(A, A + N, thrust::equal_to<int>()); // The first four values of A are now {1, 3, 2, 1} // Values beyond new_end are unspecified.
| thrust::pair<ForwardIterator1,ForwardIterator2> thrust::unique_by_key | ( | ForwardIterator1 | keys_first, |
| ForwardIterator1 | keys_last, | ||
| ForwardIterator2 | values_first | ||
| ) |
unique_by_key is a generalization of unique to key-value pairs. For each group of consecutive keys in the range [keys_first, keys_last) that are equal, unique_by_key removes all but the first element of the group. Similarly, the corresponding values in the range [values_first, values_first + (keys_last - keys_first)) are also removed.
The return value is a pair of iterators (new_keys_last,new_values_last) such that no two consecutive elements in the range [keys_first, new_keys_last) are equal.
This version of unique_by_key uses operator== to test for equality and project1st to reduce values with equal keys.
| keys_first | The beginning of the key range. |
| keys_last | The end of the key range. |
| values_first | The beginning of the value range. |
[key_first, keys_new_last) and [values_first, values_new_last).| ForwardIterator1 | is a model of Forward Iterator, and ForwardIterator1 is mutable, and ForwardIterator's value_type is a model of Equality Comparable. |
| ForwardIterator2 | is a model of Forward Iterator, and ForwardIterator2 is mutable. |
The following code snippet demonstrates how to use unique_by_key to compact a sequence of key/value pairs to remove consecutive duplicates.
#include <thrust/unique.h> ... const int N = 7; int A[N] = {1, 3, 3, 3, 2, 2, 1}; // keys int B[N] = {9, 8, 7, 6, 5, 4, 3}; // values thrust::pair<int*,int*> new_end; new_end = thrust::unique_by_key(A, A + N, B); // The first four keys in A are now {1, 3, 2, 1} and new_end.first - A is 4. // The first four values in B are now {9, 8, 5, 3} and new_end.second - B is 4.
| thrust::pair<ForwardIterator1,ForwardIterator2> thrust::unique_by_key | ( | ForwardIterator1 | keys_first, |
| ForwardIterator1 | keys_last, | ||
| ForwardIterator2 | values_first, | ||
| BinaryPredicate | binary_pred | ||
| ) |
unique_by_key is a generalization of unique to key-value pairs. For each group of consecutive keys in the range [keys_first, keys_last) that are equal, unique_by_key removes all but the first element of the group. Similarly, the corresponding values in the range [values_first, values_first + (keys_last - keys_first)) are also removed.
This version of unique_by_key uses the function object binary_pred to test for equality and project1st to reduce values with equal keys.
| keys_first | The beginning of the key range. |
| keys_last | The end of the key range. |
| values_first | The beginning of the value range. |
| binary_pred | The binary predicate used to determine equality. |
[first, new_last).| ForwardIterator1 | is a model of Forward Iterator, and ForwardIterator1 is mutable, and ForwardIterator's value_type is a model of Equality Comparable. |
| ForwardIterator2 | is a model of Forward Iterator, and ForwardIterator2 is mutable. |
| BinaryPredicate | is a model of Binary Predicate. |
The following code snippet demonstrates how to use unique_by_key to compact a sequence of key/value pairs to remove consecutive duplicates.
#include <thrust/unique.h> ... const int N = 7; int A[N] = {1, 3, 3, 3, 2, 2, 1}; // keys int B[N] = {9, 8, 7, 6, 5, 4, 3}; // values thrust::pair<int*,int*> new_end; thrust::equal_to<int> binary_pred; new_end = thrust::unique_by_key(keys, keys + N, values, binary_pred); // The first four keys in A are now {1, 3, 2, 1} and new_end.first - A is 4. // The first four values in B are now {9, 8, 5, 3} and new_end.second - B is 4.
| thrust::pair<OutputIterator1,OutputIterator2> thrust::unique_by_key_copy | ( | InputIterator1 | keys_first, |
| InputIterator1 | keys_last, | ||
| InputIterator2 | values_first, | ||
| OutputIterator1 | keys_output, | ||
| OutputIterator2 | values_output | ||
| ) |
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_output and the corresponding values from the range [values_first, values_first + (keys_last - keys_first)) are copied to a range beginning with values_output.
This version of unique_by_key_copy uses operator== to test for equality and project1st to reduce values with equal keys.
| 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_output | The beginning of the output key range. |
| values_output | The beginning of the output value range. |
[keys_output, keys_output_last) and [values_output, values_output_last).| 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. |
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.
| thrust::pair<OutputIterator1,OutputIterator2> thrust::unique_by_key_copy | ( | InputIterator1 | keys_first, |
| InputIterator1 | keys_last, | ||
| InputIterator2 | values_first, | ||
| OutputIterator1 | keys_output, | ||
| OutputIterator2 | values_output, | ||
| 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_output and the corresponding values from the range [values_first, values_first + (keys_last - keys_first)) are copied to a range beginning with values_output.
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.
| 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_output | The beginning of the output key range. |
| values_output | The beginning of the output value range. |
| binary_pred | The binary predicate used to determine equality. |
[keys_output, keys_output_last) and [values_output, values_output_last).| 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. |
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; thrust::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.
| OutputIterator thrust::unique_copy | ( | InputIterator | first, |
| InputIterator | last, | ||
| OutputIterator | output | ||
| ) |
unique_copy copies elements from the range [first, last) to a range beginning with output, except that in a consecutive group of duplicate elements only the first one is copied. The return value is the end of the range to which the elements are copied.
The reason there are two different versions of unique_copy is that there are two different definitions of what it means for a consecutive group of elements to be duplicates. In the first version, the test is simple equality: the elements in a range [f, l) are duplicates if, for every iterator i in the range, either i == f or else *i == *(i-1). In the second, the test is an arbitrary BinaryPredicate binary_pred: the elements in [f, l) are duplicates if, for every iterator i in the range, either i == f or else binary_pred(*i, *(i-1)) is true.
This version of unique_copy uses operator== to test for equality.
| first | The beginning of the input range. |
| last | The end of the input range. |
| output | The beginning of the output range. |
[output, output_end).| InputIterator | is a model of Input Iterator, and InputIterator's value_type is a model of Equality Comparable. |
| OutputIterator | is a model of Output Iterator and and InputIterator's value_type is convertible to OutputIterator's value_type. |
The following code snippet demonstrates how to use unique_copy to compact a sequence of numbers to remove consecutive duplicates.
#include <thrust/unique.h> ... const int N = 7; int A[N] = {1, 3, 3, 3, 2, 2, 1}; int B[N]; int * output_end = thrust::unique_copy(A, A + N, B); // The first four values of B are now {1, 3, 2, 1} and (output_end - B) is 4 // Values beyond output_end are unspecified
| OutputIterator thrust::unique_copy | ( | InputIterator | first, |
| InputIterator | last, | ||
| OutputIterator | output, | ||
| BinaryPredicate | binary_pred | ||
| ) |
unique_copy copies elements from the range [first, last) to a range beginning with output, except that in a consecutive group of duplicate elements only the first one is copied. The return value is the end of the range to which the elements are copied.
This version of unique_copy uses the function object binary_pred to test for equality.
| first | The beginning of the input range. |
| last | The end of the input range. |
| output | The beginning of the output range. |
| binary_pred | The binary predicate used to determine equality. |
[output, output_end).| InputIterator | is a model of Input Iterator, and InputIterator's value_type is a model of Equality Comparable. |
| OutputIterator | is a model of Output Iterator and and InputIterator's value_type is convertible to OutputIterator's value_type. |
| BinaryPredicate | is a model of Binary Predicate. |
The following code snippet demonstrates how to use unique_copy to compact a sequence of numbers to remove consecutive duplicates.
#include <thrust/unique.h> ... const int N = 7; int A[N] = {1, 3, 3, 3, 2, 2, 1}; int B[N]; int *output_end = thrust::unique_copy(A, A + N, B, thrust::equal_to<int>()); // The first four values of B are now {1, 3, 2, 1} and (output_end - B) is 4 // Values beyond output_end are unspecified.
1.7.6.1