FreeBSD Manual Pages
std::inclusive_scan(3) C++ Standard Libary std::inclusive_scan(3) NAME std::inclusive_scan - std::inclusive_scan Synopsis Defined in header <numeric> template< class InputIt, class OutputIt > (since C++17) OutputIt inclusive_scan( InputIt first, (until C++20) InputIt last, OutputIt d_first ); template< class InputIt, class OutputIt > constexpr OutputIt inclusive_scan( (since C++20) InputIt first, InputIt last, OutputIt d_first ); template< class ExecutionPolicy, class ForwardIt1, class ForwardIt2 > ForwardtIt2 inclusive_scan( (2) (since C++17) ExecutionPolicy&& policy, ForwardIt1 first, ForwardIt1 last, ForwardIt2 d_first ); template< class InputIt, class OutputIt, class BinaryOperation > OutputIt inclusive_scan( InputIt first, (since C++17) InputIt last, (un- til C++20) OutputIt d_first, BinaryOperation binary_op ); template< class InputIt, class OutputIt, class BinaryOperation > constexpr OutputIt inclusive_scan( (since C++20) InputIt first, InputIt last, OutputIt d_first, BinaryOperation (1) binary_op ); template< class ExecutionPolicy, class ForwardIt1, class ForwardIt2, class BinaryOperation > ForwardIt2 inclusive_scan( (4) (since C++17) ExecutionPolicy&& policy, ForwardIt1 first, ForwardIt1 last, ForwardIt2 d_first, BinaryOperation binary_op ); (3) template< class InputIt, class OutputIt, class BinaryOperation, class T > (since C++17) OutputIt inclusive_scan( InputIt first, (until InputIt last, OutputIt d_first, C++20) BinaryOperation binary_op, T init ); template< class InputIt, class OutputIt, class BinaryOperation, class T > constexpr OutputIt inclusive_scan( (since InputIt first, InputIt last, OutputIt C++20) d_first, (5) BinaryOperation binary_op, T init ); template< class ExecutionPolicy, class ForwardIt1, class ForwardIt2, class BinaryOperation, class T > ForwardIt2 inclusive_scan( (6) (since ExecutionPolicy&& policy, C++17) ForwardIt1 first, ForwardIt1 last, ForwardIt2 d_first, BinaryOperation binary_op, T init ); Computes an inclusive prefix sum operation using binary_op (or std::plus<>() for overloads (1-2)) for the range [first, last), using init as the ini- tial value (if provided), and writes the results to the range beginning at d_first. "inclusive" means that the i-th input element is included in the i-th sum. Formally, assigns through each iterator i in [d_first, d_first + (last - first)) the value of: * for overloads (1-4), the generalized noncommutative sum of *j... for every j in [first, first + (i - d_first + 1)) over binary_op * for overloads (5-6), the generalized noncommutative sum of init, *j... for every j in [first, first + (i - d_first + 1)) over binary_op where generalized noncommutative sum GNSUM(op, a 1, ..., a N) is defined as follows: * if N=1, a 1 * if N > 1, op(GNSUM(op, a 1, ..., a K), GNSUM(op, a M, ..., a N)) for any K where 1 < K+1 = M N In other words, the summation operations may be performed in arbi- trary order, and the behavior is nondeterministic 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>> (until C++20) std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>> (since C++20) is true. binary_op shall not invalidate iterators (including the end itera- tors) or subranges, nor modify elements in the ranges [first, last) or [d_first, d_first + (last - first)). Otherwise, the behavior is undefined. Parameters first, last - the range of elements to sum d_first - the beginning of the destination range; may be equal to first policy - the execution policy to use. See execution policy for details. init - the initial value (optional) binary FunctionObject that will be applied in to the result of binary_op - dereferencing the input iterators, the results of other binary_op, and init (if provided). Type requirements - InputIt must meet the requirements of LegacyInputIterator. - OutputIt must meet the requirements of LegacyOutputIterator. - ForwardIt1 must meet the requirements of LegacyForwardIterator. - ForwardIt2 must meet the requirements of LegacyForwardIterator. - If init is not provided, decltype(first)'s value_type must be Move- Constructible and binary_op(*first, *first) must be convertible to decltype(first)'s value type. - T (if init is provided) must meet the requirements of MoveCon- structible. All of binary_op(init, *first), binary_op(init, init), and bi- nary_op(*first, *first) must be convertible to T Return value Iterator to the element past the last element written. Complexity O(last - first) applications of the binary operation Exceptions The overloads with a template parameter named ExecutionPolicy report errors as follows: * If execution of a function invoked as part of the algorithm throws an exception and ExecutionPolicy is one of the standard policies, std::termi- nate is called. For any other ExecutionPolicy, the behavior is implementation- defined. * If the algorithm fails to allocate memory, std::bad_alloc is thrown. Example // Run this code #include <functional> #include <iostream> #include <iterator> #include <numeric> #include <vector> int main() { std::vector data {3, 1, 4, 1, 5, 9, 2, 6}; std::cout << "exclusive sum: "; std::exclusive_scan(data.begin(), data.end(), std::ostream_iterator<int>(std::cout, " "), 0); std::cout << "\ninclusive sum: "; std::inclusive_scan(data.begin(), data.end(), std::ostream_iterator<int>(std::cout, " ")); std::cout << "\n\nexclusive product: "; std::exclusive_scan(data.begin(), data.end(), std::ostream_iterator<int>(std::cout, " "), 1, std::multiplies<>{}); std::cout << "\ninclusive product: "; std::inclusive_scan(data.begin(), data.end(), std::ostream_iterator<int>(std::cout, " "), std::multiplies<>{}); } Output: exclusive sum: 0 3 4 8 9 14 23 25 inclusive sum: 3 4 8 9 14 23 25 31 exclusive product: 1 3 3 12 12 60 540 1080 inclusive product: 3 3 12 12 60 540 1080 6480 See also computes the differences between adjacent elements in a adjacent_difference range (function template) accumulate sums up a range of elements (function template) partial_sum computes the partial sum of a range of ele- ments (function template) transform_inclusive_scan applies an invocable, then calculates in- clusive scan (C++17) (function template) exclusive_scan similar to std::partial_sum, excludes the ith input element (C++17) from the ith sum (function template) http://cppreference.com 2022.07.31 std::inclusive_scan(3)
NAME | Synopsis | Parameters | Type requirements | Return value | Complexity | Exceptions | Example | Output: | See also
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=std::inclusive_scan&sektion=3&manpath=FreeBSD+Ports+15.0>