\subsubsection{Writing fast code}
Improving the speed of the code can be done by optimizing the code's locality (both temporal and spatial locality).

Computing a matrix product or iterating over a list can be much faster depending on the way you access the array and how it is stored.

A common tactic to improve the throughput for these kinds of operations is to make sure that the order of operations is correct
(i.e. for a row-major matrix to iterate over the elements of a row in the inner loop),
or to do block multiplication where you multiply small blocks at once.