Re: [fluka-discuss]: problem with MAGFLD routine in new FLUKA release

From: Stefan E. Mueller <stefan.mueller_at_hzdr.de>
Date: Thu, 23 Dec 2021 21:46:52 +0100 (CET)

Dear Lev,

it may be that numerical checks have become more strict with the new
version. Anyway, what happens if you do

BTZ = DSQRT(2.D0*BTZ**2+BTY**2+BTX**2-1.D0)

or even more simple

BTZ = DSQRT( ONEONE - BTX**2 - BTY**2 )

?

Is there a difference if you print the norm for UaMGFLD, VMGFLD, WMGFLD
and
your BTX, BTY, BTZ:

WRITE(*,*) 'NORM of UMGFLD, VMGFLD, WMGFLD: ', DSQRT(UMGFLD**2 + VMGFLD**2
+ WMGFLD**2)

WRITE(*,*) 'NORM of BTX, BTY, BTZ: ', DSQRT(BTX**2 + BTY**2
+ BTZ**2)

? (This should appear in the .log file in output)

Cheers,

         Stefan

--
Stefan E. Mueller
Department of Information Services and Computing - Computational Science
and Institute of Radiation Physics
Helmholtz-Zentrum Dresden-Rossendorf
Tel: +49 (0351) 260 3847
Stefan.Mueller_at_hzdr.de
http://www.hzdr.de
Vorstand: Prof. Dr. Sebastian M. Schmidt, Dr. Diana Stiller
Vereinsregister: VR 1693 beim Amtsgericht Dresden
On Thu, 23 Dec 2021, Lev Shekhtman wrote:
> Dear Stefan, thank you for your reply. In my code (see attached to my first 
> mail) I have the following lines:
>
> DOUBLE PRECISION BTX,BTY,BTZ,B,BR,BZ
> ...
> BTZ = DSQRT(2*BTZ**2+BTY**2+BTX**2-1.D0)
>
> In previous FLUKA releases this worked properly and there was no complain 
> about normalization. Why it does not work in the new one?
>
> Regards, Lev.
>
>
> On Wed, 22 Dec 2021, Stefan E. Mueller wrote:
>
>> Dear Lev,
>> 
>> it seems to me that FLUKA is complaining about the normalization of the 
>> BTX, BTY, BTZ values. From the manual (MGNFIELD card, Note2) ):
>> 
>> (I)t is imperative that MAGFLD returns normalised values of BTX, BTY and 
>> BTZ such that the sum of their squares is = 1.0
>> IN DOUBLE PRECISION.
>> 
>> Apparently, for your values this condition is not fulfilled (while it is 
>> the case for the pre-defined UMGFLD, VMGFLD, WMGFLD values in the 
>> CMEMFL-common, so if you have those values override your BTX, BTY, BTZ this 
>> will of course work).
>> 
>> Cheers,
>>
>> 	Stefan
>> 
>> --
>> Stefan E. Mueller
>> Department of Information Services and Computing - Computational Science
>> and Institute of Radiation Physics
>> Helmholtz-Zentrum Dresden-Rossendorf
>> Tel: +49 (0351) 260 3847
>> Stefan.Mueller_at_hzdr.de
>> http://www.hzdr.de
>> 
>> Vorstand: Prof. Dr. Sebastian M. Schmidt, Dr. Diana Stiller
>> Vereinsregister: VR 1693 beim Amtsgericht Dresden
>> 
>> On Tue, 2 Nov 2021, Lev Shekhtman wrote:
>>
>>>  Dear FLUKA experts, I got a problem with new FLUKA release. My MAGFLD
>>>  routine does not work any more. The old and new versions of MAGFLD are
>>>  attached to this mail. The old version was working properly with 2018,
>>>  2019 and 2020 releases. In the last release there are the following lines
>>>  added:
>>>
>>>       BTX   = UMGFLD
>>>       BTY   = VMGFLD
>>>       BTZ   = WMGFLD
>>>       B     = BIFUNI
>>>
>>>  that overwrite my field. If I remove them I get the following error:
>>>
>>>  Abort called from MAGNEW reason U/V/WMGCUR UNNORMALIZED !! Run stopped!
>>>  STOP U/V/WMGCUR UNNORMALIZED !!
>>>
>>>  The same I get if I put my code after these lines. Please help.
>>>
>>>  With best regards, Lev Shekhtman.
>>> 
>>> 
>> 
>



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Received on Fri Dec 24 2021 - 00:24:19 CET

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