Expert Python Programming - Second Edition

Caching

When some of your application function takes too long to compute, the useful technique to consider is caching. Caching is nothing but saving a return value for future reference. The result of a function or method that is expensive to run can be cached as long as:

• The function is deterministic and the results have the same value every time, given the same input
• The return value of the function continues to be useful and valid for some period of time (nondeterministic)

In other words, a deterministic function always returns the same result for the same set of arguments, whereas a nondeterministic one returns results that may vary in time. Such an approach usually greatly reduces the time of computation and allows you to save a lot of computer ...