[Tutor] Structure of my simulation / monte-carlo

[Kent Johnson]

On Sat, Oct 31, 2009 at 12:54 PM, Vincent Davis
<vincent at vincentdavis.net> wrote:

> So my plan way to make a new class. This class would define the Applicant
> characteristics "self.gpa = random.gauss(mean, SD)" and the
> institutions self.quality = random.gauss(mean, sd)
> so it would look something like this
>
> class RepeatMatch:
>     def __int__(self, app_mean, app_sd, inst_mean, inst_sd, match_ repeat)
>         self.app_mean = app_mean
>         ……..
>         self.match_repeat = match_repeat
>    def makeApplicants():
>    def makeInstitutions():
>    def runMatches(self)
>    # runs the match match_repeat number of times, saves results
> # then I calculate some characteristics of the results
>     def ratio_dist():
>          # returns the Mean and sd of GPA/Quality
> END OF CODE
> Does it make sense to do it this way? Is there a better/alternative way of
> thinking about this. In the end I want to compare the results of repeated
> simulations "RepeatMatch(50,2….) Compared to RepeatMatch(50,15….)"
> This is way I had ask the earlier question "class attribute to initiate more
> classes"

This class has a lot of responsibilities:
- create applicants
- create institutions
- run a single match
- run multiple matches
- calculate statistics on the result of multiple matches

A principle of object-oriented design is that a class should have a
single responsibility. I would break your class up a bit using
multiple classes, perhaps
MatchParameters - holds app_mean, etc
Match - create applicants and institutions and run a single match,
yielding a MatchResult
MatchResult - the result of running a single match
RepeatMatch - run multiple matches and accumulate results, yielding a
RepeatResults
RepeatResults - the result of running multiple matches - knows how to
compute stats on itself

You may think of better names, or a different way to organize it, but
the idea is, don't shove everything into one class. Some of these may
be just built-in data structures or very simple classes, such as
MatchParameters which might be a dict or a collections.namedtuple.

Kent