Re: A logic code error (possibly?)

Dear Joseph,

thank you for the bug report. There was indeed an error in the bounding
box routine for the ARB. Internally the ARB's are converted to planes,
as the code stores the plane coefficients in the same memory location
with the vertices, the bounding box information was lost. As result the
optimizer was canceling the Wedge since it was appearing(wrongly) not to
have any overlap with the HK1D2a.
The code is fixed and a patch will be provided with the next respin.
In the mean time to have it working you can disable the bounding box
optimization by setting the GEOBEGIN.WHAT(5)=2

However you are heavily using parenthesis in the description of the
World, which expands to several thousand terms and with bounding box
optimization off would result in slow execution.

Cheers
Vasilis

On 06/25/10 03:46, Joseph Comfort wrote:
> I have continued to work on the 'difficult geometry problem,' and have
> overcome many issues (some logical errors, alternative approaches,...).
> I am very close to a working file. I thought I had my 'final' bug fix,
> only to be surprised by new error messages. They are of the form that a
> point is in more than one region when I had clearly subtracted a body
> from one region so it could be used in a different region.
>
> I attach two input files: ni30_n.inp (which sort-of fails) and
> ni30_n_noD2.inp (which runs successfully, for at least 1000 events).
> The .err and .out files from the first case are also attached. Very
> puzzling is the fact that, even though many geometry errors are listed,
> the case still runs events.
>
> The difference in the cases is whether a region (dipole magnet) with a
> couple of adjacent holes through it, along with the definitions of the
> holes, surrounds a beam pipe with a wedge-like extraction region for a
> beam. A couple of beam pipes, which join at a 13 deg angle, must be
> subtracted from one of the holes. This appears not to be a problem. But
> the wedge must also be subtracted from both holes, and defined as a
> separate region. The body 'Wedge' (a BOX with cuts) is subtracted from
> the hole HK1D2 to form the region 'HoleD2a', but points that are inside
> Wedge are still said to be in that region.
>
> My region definition is
> HoleD2a 3 +HK1D2a -Wedge
> -( | (+Pipe3a +BndPln) | (+Pipe3b -BndPln) )
> The idea is that Pipe3a and Pipe3b are to be removed from the hole, as
> well as any part of Wedge that is in it. (Because the pipes are defined
> beyond the joining locations at the bend, they are cut by a plane.)
>
> The program output translates this definition to
> OR +HK1D2a -Pipe3a -Pipe3b
> OR +HK1D2a -BndPln -Pipe3b
> OR +BndPln +HK1D2a -Pipe3a
>
> I do not believe these statements are equivalent to my intent. But most
> importantly, Wedge is not subtracted at all. Hence the error messages.
>
> I have tried many variations of my definition (one is commented out),
> with no success. It is possible that I have misinterpreted something,
> or there is some kind of other geometry problem elsewhere. The
> combinatorial logic is not easy to digest, and is even more puzzling
> when the code does major rearrangements of the input. I am suspecting a
> coding error.
>
> BTW, I rebuilt the input file in stages, testing each stage with the
> geometry debugger and also with large numbers of actual beam particles
> (from a source file). This case is pretty much the last stage.
>
> As always, ideas would be appreciated.
>
> Thank you,
> Joe Comfort
>

-- 
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Vasilis Vlachoudis
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