thrust::exclusive_scan

Defined in thrust/scan.h

template<typename InputIterator, typename OutputIterator, typename T> OutputIterator thrust::exclusive_scan(InputIterator first, InputIterator last, OutputIterator result, T init)

exclusive_scan computes an exclusive prefix sum operation. The term ‘exclusive’ means that each result does not include the corresponding input operand in the partial sum. More precisely, init is assigned to *result and the sum of init and *first is assigned to *(result + 1), and so on. This version of exclusive_scan assumes plus as the associative operator but requires an initial value init. When the input and output sequences are the same, the scan is performed in-place.

Results are not deterministic for pseudo-associative operators (e.g., addition of floating-point types). Results for pseudo-associative operators may vary from run to run.

The following code snippet demonstrates how to use exclusive_scan

#include <thrust/scan.h>

int data[6] = {1, 0, 2, 2, 1, 3};

thrust::exclusive_scan(data, data + 6, data, 4); // in-place scan

// data is now {4, 5, 5, 7, 9, 10}