I agree that epsilons should be used .. I stated this in my post but I
somehow that was missed ...
This does not only apply to == .. it applies to <> as well.
If you prefer as an example ...
float f = 97.09f * 100f;
bool test = f > 97.09f * 99.999999f;
Console.WriteLine(test);
My point is that this is a breaking change from 1.x as an optimization (btw
your code for doing with this with an epsilon would be on the order of 10
times slower compared to the narrowing). Also keep in mind I am bringing
this up not for myself but for the thousands of people who will sit there
and scratch their heads for a week at this code who did not have such issues
in 1.x. What will really get them is the fact it only occurs in "production"
code. No amount of debugging will ever find this for them.
Just to be clear, I agreee 100% that equalities should not be done (I even
put this in the post). I also think that if telling the compiler to do
narrowing for you does not happen that it should fall onto the compiler to
tell you that you are breaking the rule to help prevent it.
Keep in mind that these suggestions are focused at people who will not
understand this discussion (in fact they would probably never read it),
these people represent the majority of C#/VB.NET developers. Having the
compiler check for tests such as these (and to force narrowing) is a trivial
task and would make their code work without them thinking about it. If you
don't believe the assumption on the majority of developers I invite you to
nearly any question/answer site.
Surely more complex compiler or JIT optimizations will be coming soon .. at
which point flags will be needed anyways.
I was trying to focus on a business vs academic discussion .. I know the
academic answer.
btw: I see code atleast once a day doing equality checks between floating
points.
Cheers,
Greg
On 6/5/06, Miguel de Icaza <[EMAIL PROTECTED]> wrote:
Hello,
> The root of this specific problem is breaking the commandments of
> floating-point:
To complement this, I like this article:
"What Every Computer Scientist Should Know About Floating-Point
Arithmetic":
http://docs.sun.com/source/806-3568/ncg_goldberg.html
Miguel
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