On Sun, Nov 15, 2009 at 5:32 PM, Eleanor McHugh
<eleanor / games-with-brains.com> wrote:
> On 15 Nov 2009, at 23:02, Marnen Laibow-Koser wrote:
>>
>> Rick Denatale wrote:
>>>
>>> When I was a young lad, it used to be that young programmers took a
>>> semester long course on numerical analysis, which started with, and
>>> continuously came back to dealing with the properties of floating
>>> point numbers.
>>>
>>> I guess that doesn't happen much anymore.
>>
>> Again, I could do that or (more likely) find out how to do it.  But why
>> bother when wise use of BigDecimal and Rational will completely obviate
>> the need?
>
> The physical limitations imposed on arbitrary-precision decimal computation
> by binary representation are something you should know *before* arguing that
> one representation is better than another.

I think Marnen originally was suggesting that the imprecisions will
stack, like an arrow at a target going more and more off course during
its flight, of course depending on the application.  For some apps,
it's totally reasonable to see something go chaotic because of these
things.

For a short and unimportant game I'm playing, I wouldn't be upset.
But, for a game that takes 10's of hours and have it ride my butt
later at a crucial moment, I might just call that a bug.

Does the imprecision in the calculation stack in ballistic calcs?  A
virtual magic bullet as it were?  I'm not sure, but I'm guessing it
doesn't to great effect.

Todd