RE: Trackr common is full!!, increase the Mxtrck parameter

From: Chrysostomos Valderanis <Chrysostomos.Valderanis_at_cern.ch>
Date: Mon, 25 Oct 2010 16:40:37 +0200

Dear Vasili,

In fact I was planning the other way. I want to force Fluka transporting
through the magnetic field in one step, while keeping the accuracy.
Since I am asking for transport in vacuum it shouldn't matter. Is this
possible?
I was under the impression that transporting in vacuum shouldn't cost in
time since the solution is known analytically. Is this the case?

Thank you again,
Makis

________________________________

From: Vasilis Vlachoudis
Sent: Mon 25/10/2010 16:18
To: Chrysostomos Valderanis=20
Cc: fluka-discuss_at_fluka.org
Subject: Re: Trackr common is full!!, increase the Mxtrck parameter

Hi Maki,

then you have to find a suitable combination with the STEPSIZE and
MGNFIELD cards for the Minimum, Maximum step, Boundary accuracy and Max
angle.
In your case you were requesting a maximum angle (default) 57deg,
boundary accuracy of 1e-10cm and Maximum step of 700cm. It was ending,
by breaking the 57deg into too many substeps more than the maximum limit
in the trackr common of 2500.
To go to 1e-10 accuracy (which will exploded your CPU tracking time and
it wont make any sense either for the calculation) reduce the maximum
step in STEPSIZE down to 0.1cm

Cheers
Vasilis

On 10/25/10 10:55, Chrysostomos Valderanis wrote:

        Dear Vasili,
        
        Thank you very much for the explanation. But putting 1e-4 to WHAT(2) is
something I would prefer to avoid. I really would like to be able to
have double precision accuracy in my tracking under the magnetic field
and asking for a boundary accuracy of 1e-4 is not helping me. So, is
there another way to achive double precision in tracking?
        
        Thank you again,
        Makis

________________________________

        From: Vasilis Vlachoudis
        Sent: Mon 25/10/2010 10:44
        To: Chrysostomos Valderanis
        Cc: fluka-discuss_at_fluka.org
        Subject: Re: Trackr common is full!!, increase the Mxtrck parameter

        Dear Maki,

        the problem was coming from the too small value set in WHAT(2) of
MGNFIELD. You have requested as upper limit for the boundary accuracy
1e-10cm during the tracking in the mangetic field. Therefore it was
forcing the code to make small steps to check for the boundary leading
to and overflow in the trackr common. Please increase the WHAT(2) e.g.
1e-4 and you will see that the message will disappear.
        FLUKA was displaying only the first ten messages in order not to flood
your output with such messages.

        Regards
        Vasilis

        On 10/18/10 08:31, Chrysostomos Valderanis wrote:

                Hello,
                
                I am trying to run a simple example and I get this message in the
first event of the err file. My questions
                1. Is it an error or a warning. It doesn't seem to influence the
result, but the fact that is written to the error file is worrying.
                2. Since only tracking is involved, shouldn't it be also produced in
the other events? Is it suppressed?
                3. How to avoid it? I thought that enlarging the maximum step in the
magnetic field was going to remove it, since the magnetic field region
was going to be passed in one step, but it isn't the case.
                4. changing the mxtrck parameter in the Trackr include module. It
gives an error in the linking.

                Thank you,
                Makis

        -------------------------------------------------------
        Vasilis Vlachoudis
        Dep. EN-STI-EET
        Web: home.cern.ch/bnv
        Tel: +41-22-7679851
        Fax: +41-22-7669644
        -------------------------------------------------------

-------------------------------------------------------
Vasilis Vlachoudis
Dep. EN-STI-EET
Web: home.cern.ch/bnv
Tel: +41-22-7679851
Fax: +41-22-7669644
-------------------------------------------------------
Received on Tue Oct 26 2010 - 08:46:05 CEST

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