Changing the floating point arithmetic model in asp.net -- pleasehelp

  • Thread starter Thread starter almurph
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A

almurph

Folks,


I'm writing C# in Visual Studio v9.0.2 using the ASP.NET framework
v3.5 and am trying to manipulate the floating point arithmetic model
that the ASP.NET framework uses.

I would appreciate any user comments/experiences that you may want to
share.

I ask as I am trying to emulate the C compiler behaviour for some
code have I have converted. I tried using the System.Single type and
noticed some minor improvements. I then wrote a method in C++ and
imported this as as a DLL. Once again I noticed an improvement (by the
word improvment what I mean is that the calculation is closer to the C
equivalent).

However the small differences tend to build up and go pair-shaped
after a few loops.

So, I would appreciate any user comments/experiences that you may
want to share.

Cheers,
Al.
 
That said, the short answer is: if it's important to you for the results  
to be _identical_ no matter which implementation of floating point code  
you use, then you've either got a problem with your problem description or  
your choice of implementation (i.e. using floating point).

Floating point simply isn't suitable for bit-precise results.  Rounding 
error accumulates, and is dependent on the inputs.  If floating point  
calculations are suitable, there's no use in expecting exact results,  
because that's simply impossible.
Click to expand...

I would disagree. Floating point is quite suitable for _bit_-precise
results - so long as your inputs are bit-for-bit the same, and the
rules are well-defined (e.g. IEEE floating-point representation and
operations), the result should be bit-for-bit the same, too.

Of course, I doubt that the original poster actually needs that.
 
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