Table 1 Time complexity estimations of the steps of the random swap algorithm, and the observed numbers as the averages over the first 500 iterations for data set Bridge (N = 4096, k = 256, N/k = 16, α ≈ 8)
Step | Time complexity | Observed number of steps at iteration | ||
|---|---|---|---|---|
50 | 100 | 500 | ||
Prototype swap | 2 | 2 | 2 | 2 |
Cluster removal | 2N | 7526 | 8448 | 10,137 |
Cluster addition | 2N | 8192 | 8192 | 8192 |
Prototype update | 4N/k + 2α | 53 | 61 | 60 |
K-means iterations | ≤ 4αN | 300,901 | 285,555 | 197,327 |
Total | O(αN) | 316,674 | 302,258 | 215,718 |