Geometry Boost List: Re: [geometry] Intersection precision problem

Subject: Re: [geometry] Intersection precision problem
From: Barend Gehrels (barend_at_[hidden])
Date: 2012-03-22 14:24:27

Hi Edwin,

Thanks for your report.

> If the 17th precision decimal is removed (using 16 decimals), both
> intersections behave as expected.
>
> Is this a bug, or is there a rule-of-thumb on how to handle these precision
> problems?

This has been solved in the meantime a few weeks ago. So Boost 1.49 
gives still this error, but the Boost Trunk handles it correctly. I 
could reproduce it using your program.

So hope you are able to upgrade to the Trunk (it's also possible to copy 
only Boost.Geometry from the trunk, plus (a part of) Boost.Math).

The general rule is that ttmath handles these cases correctly. I've 
never found problems with them. The next rule is that if there is an 
issue using a double precision type, it is usually solvable too, so in 
that case reports are welcome.

Regards, Barend