CGAL users discussion list

[Alejandro Aragon <>]

Well, that is subjective because for me 20 is honestly way beyond, so  
it doesn't make sense to set the precision of cout to 20 for doubles.  
Anyways, do you know by chance in which file I can find the code that  
computes the oriented side? I'm using Eclipse and you may know that  
the indexer is broken when you work with large projects.

Thanks again for replying,

Alejandro M. Aragón


On Jul 23, 2008, at 3:36 PM, Fernando Cacciola wrote:

> Alejandro Aragon wrote:
> > Oh, and for your information, the precision(20) that you suggested is
> > stupid because you're way beyond the precision for that type
>
> numeric_limits<double>::digits10 is 15 in a typical implementation,  
> so I wouldn't say 20 is way beyond that.
>
> Also, according to this paper:
>
> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2005.pdf
>
> 17 would be a reasonable precision for outputing double values in  
> decimal format
>
> > , so you're basically outputting garbage.
> What makes you think that using more decimal digits than minimally  
> required results in garbage??
>
> Try this for yourself:
>
> double d = ( 1.0 / 3.0 ) + numeric_limits<double>::epsilon() ;
>
> cout.precision(numeric_limits<double>::digits10); cout << d << endl ;
> cout.precision(20); cout << d << endl ;
> cout.precision(40); cout << d << endl ;
> cout.precision(200); cout << d << endl ;
>
> Finally: did you understand that your point IS NOT really on the  
> line because the actual coordinates are not exactly the same as the  
> decimal literals you used to initialized them?
>
> Best
>
> Fernando Cacciola
> www.geometryfactory.com
>
>
>
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