How to avoid repeated pre-calculation in django view
You could add a model (with a db table) that stores values for a, b and x.  Then for each query, you could look for an instance with a and b and return the associated x.
I am writing an API which returns json according to queries. For example: localhost/api/query?a=1&b=2. To return the json, I need to do some pre-calculations to calculate a value, say, x. The pre-calculation takes long time (several hundred milliseconds). For example, The json file returns the value of x+a+b.
When the user query localhost/api/query?a=3&b=4, x will be calculate again and this is a waste of time since x won't change for any query. The question is how can I do this pre-calculation of x for all queries (In the real app, x is not a value but a complex object returned by wrapped C++ code).