std::inclusive_scan

 

C++

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Algorithm library

Constrained algorithms and algorithms on ranges (C++20)
Constrained algorithms, e.g. ranges::copy, ranges::sort, ...
Execution policies (C++17)
is_execution_policy (C++17)   execution::seqexecution::parexecution::par_unseqexecution::unseq (C++17)    (C++17)(C++17)(C++20)	execution::sequenced_policyexecution::parallel_policyexecution::parallel_unsequenced_policyexecution::parallel_unsequenced (C++17)(C++17)(C++17)(C++20)
Non-modifying sequence operations Batch operations for_each for_each_n (C++17) Search operations all_ofany_ofnone_of (C++11)                (C++11)(C++11) countcount_if mismatch equal findfind_iffind_if_not (C++11) find_end find_first_of adjacent_find search search_n Modifying sequence operations Copy operations copycopy_if (C++11) copy_backward copy_n (C++11) move (C++11) move_backward (C++11) Swap operations swap iter_swap swap_ranges Transformation operations replacereplace_if transform replace_copyreplace_copy_if Generation operations fill fill_n generate generate_n Removing operations removeremove_if unique remove_copyremove_copy_if unique_copy Order-changing operations reverse reverse_copy rotate rotate_copy random_shuffleshuffle (until C++17)(C++11) shift_leftshift_right (C++20)(C++20) Sampling operations sample (C++17)	Sorting and related operations Partitioning operations partition partition_copy (C++11)   stable_partition is_partitioned (C++11) partition_point (C++11) Sorting operations sort stable_sort partial_sort partial_sort_copy is_sorted (C++11) is_sorted_until (C++11) nth_element Binary search operations (on partitioned ranges) lower_bound upper_bound equal_range binary_search Set operations (on sorted ranges) includes set_union set_intersection set_difference set_symmetric_difference Merge operations (on sorted ranges) merge inplace_merge Heap operations push_heap pop_heap make_heap sort_heap is_heap (C++11) is_heap_until (C++11) Minimum/maximum operations max min minmax (C++11) clamp (C++17) max_element min_element minmax_element (C++11) Lexicographical comparison operations lexicographical_compare lexicographical_compare_three_way (C++20) Permutation operations next_permutation prev_permutation is_permutation (C++11) C library qsort bsearch
Numeric operations
iota (C++11) inner_product adjacent_difference    accumulate reduce (C++17) transform_reduce (C++17)	partial_sum inclusive_scan (C++17)    exclusive_scan (C++17) transform_inclusive_scan (C++17) transform_exclusive_scan (C++17)
Operations on uninitialized memory
uninitialized_copy uninitialized_move (C++17)    uninitialized_fill uninitialized_copy_n (C++11) uninitialized_move_n (C++17) uninitialized_fill_n	destroy (C++17) destroy_n (C++17) destroy_at (C++17) construct_at (C++20)       uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17)

 

Defined in header <numeric>
template< class InputIterator, class OutputIterator > OutputIterator inclusive_scan( InputIterator first,                                InputIterator last, OutputIterator result );	(1)	(since C++17)
template< class ExecutionPolicy, class InputIterator, class OutputIterator > OutputIterator inclusive_scan( ExecutionPolicy&& policy, InputIterator first,                                InputIterator last, OutputIterator result );	(2)	(since C++17)
template< class InputIterator, class OutputIterator, class BinaryOperation > OutputIterator inclusive_scan( InputIterator first, InputIterator last,                                OutputIterator result, BinaryOperation binary_op );	(3)	(since C++17)
template< class ExecutionPolicy, class InputIterator, class OutputIterator, class BinaryOperation > OutputIterator inclusive_scan( ExecutionPolicy&& policy, InputIterator first, InputIterator last,                                OutputIterator result, BinaryOperation binary_op );	(4)	(since C++17)
template< class InputIterator, class OutputIterator, class BinaryOperation > OutputIterator inclusive_scan( InputIterator first, InputIterator last,                                OutputIterator result, BinaryOperation binary_op, T init );	(5)	(since C++17)
template< class ExecutionPolicy, class InputIterator, class OutputIterator, class BinaryOperation > OutputIterator inclusive_scan( ExecutionPolicy&& policy, InputIterator first, InputIterator last,                                OutputIterator result, BinaryOperation binary_op, T init );	(6)	(since C++17)

Computes an inclusive prefix sum operation using binary_op (or std::plus<>() for overloads (1-2)) for the range [first, last), and writes them to the range beginning at result. "inclusive" means that the i-th input element is included in the i-th sum.

Formally, assigns through each iterator i in [result, result + (last - first)) the value of:

• for overloads (1-4), the generalized noncommutative sum of *first, *(first + 1), ..., *(first + (i - result)) over binary_op
• for overloads (5-6), the generalized noncommutative sum of init and *first, *(first + 1), ..., *(first + (i - result)) over binary_op

where generalized noncommutative sum GNSUM(op, a1, ..., aN) is defined as follows:

• if N=1, a1
• if N > 1, op(GNSUM(op, a1, ..., aK), GNSUM(op, aM, ..., aN)) for any K where 1 < K+1 = M ≤ N

In other words, the summation operations may be performed in arbitrary order.

The behavior is indeterministic if binary_op is not associative.

Overloads (2,4,6) are executed according to policy. These overloads do not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true.

op must not invalidate any iterators, including the end iterators, or modify any elements of the ranges involved.

Parameters

first, last	-	the range of elements to sum
result	-	the beginning of the destination range
policy	-	the execution policy to use. See execution policy for details.
init	-	Optional initial value
binary_op	-	binary Template:concept that will be applied in to the result of dereferencing the input iterators, the results of other binary_op, and init (if provided).
Type requirements

Return value

Iterator to the element past the last element written.

Complexity

O(last - first) applications of the binary operation

See also

adjacent_difference	computes the differences between adjacent elements in a range (function template)
accumulate	sums up or folds a range of elements (function template)
partial_sum	computes the partial sum of a range of elements (function template)
transform_inclusive_scan (C++17)	applies an invocable, then calculates inclusive scan (function template)
exclusive_scan (C++17)	similar to std::partial_sum, excludes the ith input element from the ith sum (function template)