CUDA Toolkit 10.0 sortingNetworks sample

Accelerated Computing CUDA CUDA Programming and Performance
#1

In the sortingNetworks example, why does every test show NOT stable? What does this mean?

Starting up CUDA context…
gpuDeviceInit() CUDA Device [0]: "Quadro P2000
Allocating and initializing host arrays…

Allocating and initializing CUDA arrays…

Running GPU bitonic sort (1 identical iterations)…

Testing array length 64 (16384 arrays per batch)…
Average time: 11.171182 ms

Validating the results…
…reading back GPU results
…inspecting keys array: OK
…inspecting keys and values array: OK
…stability property: NOT stable

#2

Stable sorting algorithms maintain the relative order of records with equal keys (i.e. values).

This sorting network does not qualify as a stable sort, apparently.