Dear Roberta
strange. Could you please send me the input and the user routines?
Thanks
Paola
> Dear Paola,
> thank for your suggestion, indeed in my modified mgdraw.f I was using an
> unfitting format in writing the txt file.
>
> Anyway, now, I fixed it, using:
> 200 FORMAT(' ',A,5E25.15)
> ......
> WRITE(42.0,200),'333333',JTRACK,ETRACK-AM(JTRACK),
> $ CXTRCK,CYTRCK,CZTRCK
>
> And the values I get for CZTRCK (for angle < 0.4mrad ) are:
> CZTRCK=1 or CZTRCK=0.999999940395355E+00
> and nothing between these values.
>
> See, as an example for angle grater than 0 and less than 0.4mrad, few
> output lines below (*).
>
> So, now it doesn't seem a numerical precision issue anymore.
> Do you have any idea on how to cope with that?
> Thank you,
> Roberta
>
> (*)
> 333333 0.700000000000000E+01 0.489577674865723E+02
> -0.379900448024273E-03 0.734752029529773E-04 0.999999940395355E+00
> 333333 0.100000000000000E+01 0.398913940429688E+03
> 0.243720045546070E-03 0.187961297342554E-03 0.999999940395355E+00
> 333333 0.100000000000000E+01 0.378580841064453E+03
> 0.240417313762009E-03 0.217997265281156E-03 0.999999940395355E+00
> 333333 0.100000000000000E+01 0.398872375488281E+03
> -0.289755815174431E-03 -0.169058344908990E-03 0.999999940395355E+00
> 333333 0.100000000000000E+01 0.398769622802734E+03
> -0.195283661014400E-03 -0.303217006148770E-03 0.999999940395355E+00
> 333333 0.100000000000000E+01 0.398898071289062E+03
> 0.582441571168602E-04 0.355932890670374E-03 0.999999940395355E+00
> 333333 0.100000000000000E+01 0.398916778564453E+03
> -0.868009956320748E-04 0.254166428931057E-03 0.999999940395355E+00
>
> 2015-10-13 7:36 GMT+02:00 Paola Sala <paola.sala_at_mi.infn.it>:
>
>> Hi
>> it looks like there is some single precision variable, either in the
>> writing or reading procedure, that cuts your rounding.
>> Please check all the steps, and be sure to use double precision
>> variables
>> (the default in FLUKA) and to write them with enough decimals.
>> You might also want to try the predefined FLUKA scoring options.
>> Ciao
>> Paola
>> > Dear experts,
>> > I have a question on the numerical precision which FLUKA can get on
>> the
>> > angular distributions.
>> > I simulated a 400 GeV proton beam incident on a thick Be target, 50 cm
>> > long.
>> > I modified the mgdraw.f routine in order to get an ASCII file with the
>> > information I need.
>> > I am interested in the particles produced and going out of the target
>> at
>> > very small angle, say less than 0.2 mrad. I simulated my geometry with
>> > cylindrical symmetry along z axis, so I am interested in particles
>> with
>> > ZSCO close to 1.
>> > I see that the next value less than 1 is ZSCO=0.99999994,
>> corresponding
>> to
>> > an angle of 0.00034641 rad. So I cannot get a continuous distribution
>> in
>> > that angle range.
>> > I am attaching two plots to show you the issue, they show the polar
>> angle
>> > vs kinetic energy for neutrons, one is with angle less than 10 mrad,
>> and
>> I
>> > suppose that the distribution is reasonable, and the other is for
>> angle<1
>> > mrad.
>> > I am wondering if there is any way to increase the precision.
>> > Also, can you please tell me if the distribution I get is the expected
>> one
>> > or if you see further issues with that?
>> > Thank you,
>> > best regards,
>> > Roberta Volpe
>> >
>>
>>
>> Paola Sala
>> INFN Milano
>> tel. Milano +39-0250317374
>> tel. CERN +41-227679148
>>
>>
>
Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
__________________________________________________________________________
You can manage unsubscription from this mailing list at
https://www.fluka.org/fluka.php?id=acc_info
Received on Fri Oct 16 2015 - 08:48:40 CEST