Hi Mina,
you are 100% right stating that,
> If SDUM = USER, setting WHAT(3) = 1. for a region will suppress all calls
> to routine USIMBS during tracking inside that region.
You place WHAT(3)=2 therefore for that region you will not ignore the call
to USIMBS.
But it's also true that
> USER: importance biasing according to the user defined routine USIMBS.
>
meaning that the importance biasing it define according to the routine (and
not the RR which is taken from the input and can overridden in the UBSSET).
You mention that page 22 says on the slides of the new advanced course
shows this hint:
> WHAT(2) and WHAT(3) ≠ 1.0 (Any value ≠ 1.0)
>
Which in my opinion might be misleading because WHAT(2) govern the
modifying factor. If you place it to 2 (w/o using any UBSSET) the effect
will be of having the multiplication factor = 2.
> If I2 < I1, Russian Roulette will be played. Without any modifying factor,
> the chance of particle survival is I2/I1.
> For 0. <= M <= 1., the survival chance is modified to: 1. - M * (1. -
> I2/I1)
> It can be seen that a value M = 0. resets the chance of survival to 1.,
> namely inhibits Russian Roulette biasing.
> A value M = 1. leaves the survival chance unmodified, while any value
> between 0. and 1. INCREASES the probability of survival with respect to the
> basic setting.
> For M >= 1., the survival chance is modified to: I2/(M * I1)
> So, a value larger than 1. DECREASES the probability of survival with
> respect to the basic setting.
>
Maybe I'm wrong but this how I always understood it. It's even more
probable that my FLUKA-fu is getting rustier and I'll have to ask to my
(no-so) old master :D (added in bcc for double-checking my statement)
What is indeed true it that you haven't sent yet nor your input file nor
user routine and it's a bit inefficient to go around the original problem
> **** Doeimb: importance splitting not performed for missing room **in Emf
> stack ****
>
without attacking it directly.
I understand you might not want to send you input to the list but it would
be nice if you could send over the USIMBS routine.
Best,
Vittorio
On Mon, Apr 27, 2015 at 9:43 PM, Mina Nozar <nozarm_at_triumf.ca> wrote:
> Hi Vittorio,
>
> 1) The manual says nothing about the settings for WHAT(2) and WHAT(3) of
> the Biasing card, if SDUM is set to USER other than.
>
> *"If SDUM = USER, setting WHAT(3) = 1. for a region will suppress all
> calls to routine USIMBS during tracking inside that region.*"
>
> Logic tells me if one does not wish to bias a region, then
> a) do not have a Biasing card defined for that region
> or
> b) use a biasing card with SDUM = USER but set WHAT(2) and WHAT(3) to 1.
>
>
> So why just not define a biasing card for that region???
>
>
> 2) The last advanced course slide on Simulation Optimization, page 22 says
> " WHAT(2) and WHAT(3) (Any value not equal to 1).
> That is, if one wishes to call usimbs via SDUM is set to USER in the
> Biasing card. That is exactly what I have done. Setting WHAT(2) and
> WHAT(3) to 2.
> So Setting WHAT(2) and WHAT(3) to 2 does not mean I have set the
> importance and RR ratios to 2 for those regions. The importance ratio is
> determined via usimbs.f.
>
>
> Mina
>
>
>
>
>
> All your region have *importance* 2 and *RR ratio* 2.
>
> On 15-04-25 02:35 AM, Vittorio Boccone wrote:
>
> Hi Mina,
>
> sorry for the previous mail. I see that the meaning of my previous message
> was heavily affected by the automatic corrector.
>
> It would be nice to see your custom routing as well as the input.
>
> All your region have *importance* 2 and *RR ratio* 2.
> If all the regions have the same importance nothing will change.
> Vittorio
> On Apr 24, 2015 4:20 AM, "Mina Nozar" <nozarm_at_triumf.ca> wrote:
>
> >
> > Hi Vittorio,
> >
> > I am sorry, I don't understand your message.
> >
> > Do you mean you think I might be doing splitting and RR at the same
> time? How could this be?
> >
> > From the advanced course slides, I see:
> > "The Russian Roulette / Splitting will take place at the middle (defined
> by the ENTRY) of the step. "
> >
> > The same routine seems to be working for the proton beam on the target.
> So it is an issue with the electron beam. But I don't know how to go about
> investigating this. Can one of the experts/developers help please? I am
> stuck.
> >
> > Thank you,
> > Mina
> >
> >
> > On 15-04-23 01:45 PM, Vittorio Boccone wrote:
> >>
> >> HI Mina,
> >> I see you might Importance biasing and RR.
> >> Beware that the Russian Roulette massacre happens in the middle
> (defined by the ENTRY) of the steps, and not o
> >> It would be nice to see your custom usimbs.f
> >>
> >> Best,
> >> Vittorio
> >>
> >> On Thu, Apr 23, 2015 at 2:37 AM, Mina Nozar <nozarm_at_triumf.ca> wrote:
> >>>
> >>> Thanks Mario.
> >>>
> >>> But I don't think I have been too aggressive in the biasing.
> >>>
> >>> I start biasing 1 meter from the center of the target (RMIN = 100 cm)
> and bias by a factor of 2 every 35 cm (RINC) until R = 800 cm (RMAX). See
> attached image. This is what I print in the output file (for lfirst).
> >>>
> >>> ***** usimbs CALLED *****
> >>> AETE_Cx -1278.
> >>> AETE_Cy 8183.88
> >>> AETE_Cz 5948.
> >>> DMIN_IMP 0.0001
> >>> RMIN 100.
> >>> RMAX 800.
> >>> RINC 35.
> >>> 1 99999 99999
> 0.0000000E+00 1.0000000E+30 0
> >>> NEXT SEEDS: E9 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> 2000 98000 98000
> 5.6441402E-04 1.0000000E+30 133
> >>> NEXT SEEDS: 2C8E4A 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> 4000 96000 96000
> 5.5066633E-04 1.0000000E+30 255
> >>> NEXT SEEDS: 57629D 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> ...
> >>> ...
> >>>
> >>> In the .err file, I see:
> >>>
> >>>
> >>> NEXT SEEDS: 0 0 0 0 0 0 C6AD
> 2A4C 0 0
> >>> 1 99999 99999
> 0.0000000E+00 1.0000000E+30 0
> >>> NEXT SEEDS: E9 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> 2000 98000 98000
> 5.7591248E-04 1.0000000E+30 133
> >>> NEXT SEEDS: 2C8E4A 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> 4000 96000 96000
> 5.6066513E-04 1.0000000E+30 255
> >>> NEXT SEEDS: 57629D 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> 6000 94000 94000
> 5.9057713E-04 1.0000000E+30 409
> >>> NEXT SEEDS: 8987D8 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> 8000 92000 92000
> 5.9815907E-04 1.0000000E+30 530
> >>> NEXT SEEDS: B9BD7F 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> 10000 90000 90000
> 6.0090866E-04 1.0000000E+30 666
> >>> NEXT SEEDS: E9782F 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> 12000 88000 88000
> 6.2340530E-04 1.0000000E+30 808
> >>> NEXT SEEDS: 120B7BB 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> 14000 86000 86000
> 6.2054852E-04 1.0000000E+30 939
> >>> NEXT SEEDS: 14F66E4 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> 16000 84000 84000
> 6.1765611E-04 1.0000000E+30 1058
> >>> NEXT SEEDS: 17DC3F2 0 0 0 0 0
> C6AD 2A4C 0 0
> >>> *** Doeimb: importance splitting not performed for missing room
> >>> in Emf stack ***
> >>> *** Doeimb: importance splitting not performed for missing room
> >>> in Emf stack ***
> >>> *** Doeimb: importance splitting not performed for missing room
> >>> in Emf stack ***
> >>> *** Doeimb: importance splitting not performed for missing room
> >>> in Emf stack ***
> >>> *** Doeimb: importance splitting not performed for missing room
> >>> in Emf stack ***
> >>> *** Doeimb: importance splitting not performed for missing room
> >>> in Emf stack ***
> >>> *** Doeimb: importance splitting not performed for missing room
> >>> ...
> >>> ...
> >>>
> >>>
> >>> Thanks,
> >>> Mina
> >>>
> >>>
> >>>
> >>> On 15-04-22 02:31 PM, Santana, Mario wrote:
> >>>>
> >>>> From the message, and given that you were setting importances via
> usimbs.f, it seems that you have gone too aggressive in the biasing and you
> have filled the emf stack.
> >>>>
> >>>> This means that you set a step biasing split that was much bigger
> than the attenuation for your electrons and photons through your shielding.
> As a result, the population of electrons and photons was growing larger
> every step, and you filled the memory.
> >>>>
> >>>> Reduce the parameter by which you bias. Normally you would want to
> set that parameter so that the population of your particles of interest
> stays more or less constant.
> >>>>
> >>>> - Mario
> >>>>
> >>>> From: Mina Nozar <nozarm_at_triumf.ca>
> >>>> Date: Wednesday, April 22, 2015 12:36 PM
> >>>> To: fluka-discuss <fluka-discuss_at_fluka.org>
> >>>> Subject: [fluka-discuss]: user biasing using usimbs.f *** Doeimb:
> importance splitting not performed for missing room, in Emf stack ***
> >>>>
> >>>> Hello everyone,
> >>>>
> >>>> I have been trying to do biasing via usimbs.f. It has taken me few
> days of trial and error. I think I have fixed few issues (one of which
> resulted in a core dump).
> >>>>
> >>>> Now, I am seeing the following message repeated ad nauseam in the
> .err file. What does this message mean and how can I go about fixing it?
> >>>>
> >>>>
> >>>> *** Doeimb: importance splitting not performed for missing room
> >>>> in Emf stack ***
> >>>>
> >>>>
> >>>>
> >>>> Thanks in advance,
> >>>> Mina
> >>>
> >>>
> >>
> >
>
>
>
__________________________________________________________________________
You can manage unsubscription from this mailing list at
https://www.fluka.org/fluka.php?id=acc_info
Received on Tue Apr 28 2015 - 00:27:33 CEST