This repository contains three main implementation of Lloyd's k-means algorithm:

• kmeans_cpu.c: A k-means implementation for use on a single CPU core.
• kmeans_gpu.cu: A k-means implementation for use on CUDA GPUs.
• kmeans_atomic.cu: A k-means implementation for use on CUDA GPUs, using atomic operations (for comparison purposes).

In terms of "number of cluster updates per second", these programs peak at

• kmeans_cpu.c: ~950 million computations per second
• kmeans_gpu.cu: ~65 billion computations per second
• kmeans_atomic.cu: ~575 billion computations per second (though this is only feasible for a large number of clusters)

on a system with an E5-2650v3 CPU and TITAN V GPU.

A (significantly) more detailed performance analysis can be read here.