Vectorisation

The goal of vectorisation is to improve single-core performance by making use of advanced CPU features, such as using vector or cache-management instructions. On a modern CPU, using vector instructions can theoretically improve performance by a factor of two or four, and improving cache management can improve performance by an order of magnitude. In practice, the observed improvements are much smaller, but may still be significant.

In principle, it is the compiler's task to use these instructions. In practice, our code is often too complex for the compiler to understand, and these optimisations therefore do not occur.