Geometry Boost List: Re: [geometry] Precision problem with union

Subject: Re: [geometry] Precision problem with union
From: Barend Gehrels (barend_at_[hidden])
Date: 2012-05-09 17:39:05

Hi Vasiliy,

On 8-5-2012 11:49, Vasiliy Bender wrote:
> Hi all,
>
> I am getting incorrect results using bg::union_ with double precision.
> The union of two slightly intersecting (~sharing an edge) rectangles 
> r1 and r2 covers the only one of both.
> The problem is very similar to the one described in the following 
> unanswered topic:
>
> http://boost-geometry.203548.n3.nabble.com/Severe-precision-problems-with-unions-td3423635.html
>
> I am using x86_64, GCC 4.5.1 and boost::geometry 1.49. Switching to 
> trunk (boost::geometry and boost::math) does not solve the problem.

I can reproduce your problem. Last months several enhancements has been 
made to union, but this one is not yet solved. Hope to be able to do 
that soon such that it can be included in 1.50.

The "standard" answer is that it runs fine with ttmath.

I will also look to the link you provide, thanks for this. Why it was 
unanswered I don't know - I now see there was heavy ML traffic that 
time, it is probably slipped through. Sorry about that.

Regards, Barend