[Info-vax] VMS Software Q1 '23 Update

[Simon Clubley]

On 2023-01-28, Arne Vajhøj <arne at vajhoej.dk> wrote:
> On 1/28/2023 12:46 AM, Steven Schweda wrote:
>>> I am not saying that one is better than the other [...]
>> 
>>     I am.  A reasonable test for approximate equality looks for a "small"
>> (absolute) difference between two values.
>
> Absolute difference is sensitive to the scale
> of the data.
>
> Sometimes relative difference makes more sense.
>
>>                                     Expecting two extremely close
>> values to round to the same value is not reasonable.  (That is, it
>> doesn't always happen.)
> >
>>     "Equal when rounded" might seem plausible at first glance, but (even)
>> a little thought would reveal that it's an inferior test (because it
>> gives goofy results for values close to a round-down/up decision value).
>
> Consider the case where the numbers represent money.
>
> The difference between 2.494 dollar/euro and 2.496 dollar/euro
> are less than 0.01 but ...
>

Hmmm. Do you own a red stapler by any chance ? :-)

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.