Re: 100%

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Jun 23, 2007, 01:31 UTC
Message-ID: <Pine.LNX.4.64.0706230222330.4059@racer.site>
In-Reply-To: <86abusi1fw.fsf@lola.quinscape.zz>

Hi,

On Fri, 22 Jun 2007, David Kastrup wrote:

Show 11 quoted lines

> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
> 
> > On Fri, 22 Jun 2007, David Kastrup wrote:
> >
> >> As a note aside: would it be possible to always round downwards when 
> >> computing similarities or converting between them?
> >
> > I'd rather not. This would be counterintuitive. People expect rounded 
> > values.
> 
> Which people?

Me, for one. Thank you very much.

> The people I know will expect "100% identical" or even "100.0% 
> identical" to mean identical, period.  They will be quite surprised to 
> hear that "99.95%" is supposed to be included.

Granted, 100.0% means as close as you can get to "completely" with 4 digits. But if you have an integer, you better use the complete range, rather than arbitrarily make one number more important than others.

For if you see an integer, you usually assume a rounded value. If you don't, you're hopeless.

> Also, for any kind of decision made upon percentages, it is much more 
> relevant to be able to draw a line at 50% rather than at 49.5%.

I do see too many people in my day job who take the numbers they see for absolute truths, so I cannot take that statement seriously, sorry.

> Could you name a _single_ use case where rounding down could cause an 
> actual problem or even inconvenience for people?

Could you name a _single_ use case where it does not?

I mean, honestly, really. Really, really, really. A number is only a weak _indicator_, and an integer even more so, for what is _really_ going on.

Show 8 quoted lines

> >> I very much would like to see the 100% figure reserved for identity.  
> >> This is particularly relevant when interpreting the output of 
> >> git-diff --name-status with regard to R100, C100 and similar flags.
> >
> > You should never depend on the output of --name-status if you're 
> > interested in identifying identical files, but on the object names.
> 
> Which is rather inconvenient.

Frankly, I am getting bored.

This argument crops up ever so often. "If you did that, _I_ could be more lazy, and the _hell_ with other people who expect otherwise!".

No, really.

> I _know_ that one can't rely on the output of --name-status right now.

And I _know_ that you can't rely on integer numbers. Or _any_ number which is not _completely_ precise.

Really, I am getting bored with this discussion.

Ciao, Dscho