[Tutor] class uncertainty

Roeland Rengelink r.b.rigilink@chello.nl
Tue, 28 Aug 2001 10:30:41 +0200

Roeland Rengelink wrote:
> Christopher Smith wrote:
> >
> > I've created a class which keeps track of the uncertainty in a number and
> > subsequent calculations performed with that number.  It works like this:


> >
> > def log(x):
> >         if type(x)==<the type of my class>:
> >                 return uncertain.log(x)
> >         return math.log(x)
> >
> > I would prefer the latter so the operation is as seamless as possible.
> > That's where I need the advise, though.
> >
> I think this is a good solution.

Where I was assuming you meant something like:

def log(x):
    if isinstance(x, uncertain):
        return x.log()
        return math.log(x)


class uncertain:
    def log(self):
        ...return uncertain log...
So that module uncertain provides  

- a log function that can take both exact and uncertain numbers as
- an uncertain class that knows how to do a log of an uncertain number.

Hope this helps,


"Half of what I say is nonsense. Unfortunately I don't know which half"