Re: Discrete random with given distribution ?

[Wes Groleau <wesgroleau@despammed.com>]

> > Hmmm, that's not as clumsy as I thought it would be.  :-)
>   Unfortunately, roundoff complicates it a bit.   Consider:
> Size = 10

If size is ten, you're only asking for one digit of accuracy.
You could compute three and round back down to two instead of
one.  Or you could go with method two.

> type Discrete_Things is (Apples, Bananas, Cantaloupes, Dates, Eggs);
> Probability := (Apples .. Dates => => 0.04, Eggs => 0.84);
> Integer( Probability(I) * Size) = 0 for I in Apples .. Dates
>   which is fine for a one digit accuracy, but
> Integer( Probability(I) * Size) = 8 for I = Eggs
>   leaving Lookup(9 .. 10) undefined.  And if you just select
> from Lookup(1 .. 8), then Probability of random selection = Eggs is 100%

-- 
Wes Groleau
http://freepages.rootsweb.com/~wgroleau