From: Johan Råde (rade_at_[hidden])
Date: 2008-05-05 11:10:09
John Maddock wrote:
> So, it looks like so far we have:
>
> next(val)
> prior(val)
>
> and either of
>
> representation_distance(a, b);
> discrete_distance(a, b);
I'm still a bit unhappy about calling a signed quantity a "distance".
I would prefer "difference". Let me elaborate:
To me a "distance" is a quantity that satisfies the rules:
d(x,y) >= 0
d(x,x) = 0
d(y,x) = d(x,y)
d(x,y) + d(y,z) >= d(x,z)
while a "difference" is a quantity that satisfies the rules
d(x,x) = 0
d(y,x) = -d(x,y)
d(x,y) + d(y,z) = d(x,z)
The function we are discussing satisfies the second set of rules.
--Johan