RE: [fluka-discuss]: Fw: Encountering a bug using FLUKA

From: Vasilis Vlachoudis <Vasilis.Vlachoudis_at_cern.ch>
Date: Mon, 2 Feb 2015 14:53:41 +0000

Hi Yang,

after running for some time the code crash in your source routine
When you make the normalization of the TXFLK() = SQRT(ONEONE - TZFLK()**2 - TYFLK()**2)
for one event the parenthesis expression becomes slightly negative -8.67e-19 with
a result to make an exception on the SQRT.
I personally don't like this kind of normalization, apart from the numerical error
you are losing the half space -sqrt() which you are forced to sample with another
random number
Why you don't calculate the
TXFLK() = SINTHE * SQRT( (ONEONE-COSTHE)*(ONEONE+COSTHE))
and then divide all components with the SQRT(TXFLK**2 + TYFLK**2 + TZFLK**2)

V.

________________________________
From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of Vasilis Vlachoudis [Vasilis.Vlachoudis_at_cern.ch]
Sent: 02 February 2015 09:13
To: Ñ; fluka-discuss_at_fluka.org
Subject: RE: [fluka-discuss]: Fw: Encountering a bug using FLUKA

Hi Yang Bo,

could you provide us the last random number seed (fort.2) when the crash occurs.

V.

________________________________
From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of Ñ [b-yang12_at_mails.tsinghua.edu.cn]
Sent: 31 January 2015 04:28
To: fluka-discuss_at_fluka.org
Subject: [fluka-discuss]: Fw: Encountering a bug using FLUKA





Hi£¬FLUKA experts

       I encountered a bug recently when I used FlUKA code. My model is really simple,which is that electrons with a certain spectrum and angular distribution bombards a cylindrical target£¬and the bremsstrahlung photon spectrum and dose-equivalent at different polar angles is scored using six detectors by USRBDX and AUXSCORE card. I also developed a special source program Maxwell.f to sample the incident electron energy and angle.The question is when I ran the similar input files which were only altered in random seed, some of them worked fine,but others worked in a while to automatically stop.I checked on the .out and .err files and found that It would automatically stop till FLUKA ran a certain number of particles. I also check on my input files using flair and make sure my input file is correct.I am very confused about that and hope someone can help me. the input file ,source sampling program,.out and .err file are attached. Any help will be appreciated.

Yours Sincerely£¬

Yang Bo









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Received on Mon Feb 02 2015 - 17:19:14 CET

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