ParallelScanCombine

[req.parallel_scan_combine]

A type Combine satisfies the ParallelScanCombine if it meets the following requirements:

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ParallelScanCombine Requirements: Pseudo-Signature, Semantics

Value Combine::operator()(const Value &left, const Value &right) const

Combine summaries left and right, and return the result Value type must be the same as a corresponding template parameter for parallel_scan algorithm.