This example implements inclusive and exclusive scans. For details on the algorithm used, please refer to the relevant CUDA blog entry.

Inclusive scan, or prefix sum, converts an input vector $x$ to an output vector $y$, where $y_n = \sum_{i=0}^{n}x_i$, i.e., the sum of all entries in $x$ from $0$ to $n$.

To run, call the executable with -t 0:

$ ./scan -t 0

Exclusive scan (or "all-prefix-sums") is the same as inclusive scan, but excludes the $n$-th index: $y_n = \sum_{i=0}^{n-1}x_i$.

To run, call the executable with -t 1:

$ ./scan -t 1

To run this example use the following:

$ mkdir build && cd build
$ ccmake .. # configure your backends, configure and generate (make sure to enable examples)
$ cmake --build . --target=scan -j
$ ./example/scan/scan

The example is also added as a test, where it runs 2^24 elements and inclusive scan by default. To change the number of elements scanned, use -n N. To change between inclusive/exclusive scan, use -t 0 or -t 1.