29 Numerics library [numerics]

29.8 Generalized numeric operations [numeric.ops]

29.8.8 Inclusive scan [inclusive.scan]

template<class InputIterator, class OutputIterator> OutputIterator inclusive_scan(InputIterator first, InputIterator last, OutputIterator result);

1
#

Effects: Equivalent to: 

return inclusive_scan(first, last, result, plus<>());

template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2> ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec, ForwardIterator1 first, ForwardIterator1 last, ForwardIterator2 result);

2
#

Effects: Equivalent to: 

return inclusive_scan(std::forward<ExecutionPolicy>(exec), first, last, result, plus<>());

template<class InputIterator, class OutputIterator, class BinaryOperation> OutputIterator inclusive_scan(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op); template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2, class BinaryOperation> ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec, ForwardIterator1 first, ForwardIterator1 last, ForwardIterator2 result, BinaryOperation binary_op); template<class InputIterator, class OutputIterator, class BinaryOperation, class T> OutputIterator inclusive_scan(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op, T init); template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2, class BinaryOperation, class T> ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec, ForwardIterator1 first, ForwardIterator1 last, ForwardIterator2 result, BinaryOperation binary_op, T init);

3
#

Requires:

  • (3.1)

    If init is provided, T shall be MoveConstructible (Table 23); otherwise, ForwardIterator1's value type shall be MoveConstructible.

  • (3.2)

    If init is provided, all of binary_­op(init, init), binary_­op(init, *first), and binary_­op(*first, *first) shall be convertible to T; otherwise, binary_­op(*first, *first) shall be convertible to ForwardIterator1's value type.

  • (3.3)

    binary_­op shall neither invalidate iterators or subranges, nor modify elements in the ranges [first, last] or [result, result + (last - first)].

4
#

Effects: For each integer K in [0, last - first) assigns through result + K the value of

  • (4.1)

    GENERALIZED_­NONCOMMUTATIVE_­SUM(
        binary_­op, init, *(first + 0), *(first + 1), ..., *(first + K))
    if init is provided, or

  • (4.2)

    GENERALIZED_­NONCOMMUTATIVE_­SUM(
        binary_­op, *(first + 0), *(first + 1), ..., *(first + K))
    otherwise.

5
#

Returns: The end of the resulting range beginning at result.

6
#

Complexity: O(last - first) applications of binary_­op.

7
#

Remarks: result may be equal to first.

8
#

[ Note: The difference between exclusive_­scan and inclusive_­scan is that inclusive_­scan includes the ith input element in the ith sum. If binary_­op is not mathematically associative, the behavior of inclusive_­scan may be nondeterministic.  — end note ]