# Re: Timeout error

From: Alberto Fasso' <fasso_at_SLAC.Stanford.EDU>
Date: Fri, 24 Jun 2011 04:18:11 -0700 (PDT)

Nicholas,

you are right, one run with 5E6 particles has the same error as 5 runs with
1E6 particles, BUT YOU CANNOT KNOW IT! The only way to know the error is
to run 4-5 jobs and apply the formula. The formula cannot be applied to
a single run

Alberto

On Thu, 23 Jun 2011, Nicholas Bolibruch wrote:

> Sorry to take this topic on a slight detour, but I feel that I need to
> ask this question to improve the results (and confidence) of my
> simulations.
>
> My understanding of Monte-Carlo simulation is that if I run a simulation
> with 5E6 particles in a single run, it would have the same statistical
> result as 5 independent runs at 1E6. Is there something else I'm
> missing here?
>
>
> On Wed, 2011-06-22 at 12:56 -0700, Alberto Fasso' wrote:
>> 99% is not an error! It is a flag that an error could not be calculated.
>> It needs at least 4 (better 5) independent runs to calculate a standard
>> deviation. If the number of runs is less than 4, the FLUKA analysis
>> tools print 99%. That number has no meaning, it is only a code for
>> "error not calculable"
>>
>> Alberto
>>
>>
>> On Tue, 21 Jun 2011, mir inamul haq jeri wrote:
>>
>> > Hello,
>> > I got the reason of the 99% error.This is because i was running only one
>> > batch this time while as i used to run 5 batches previously.So i would say
>> > that each run serves as a batch of particles and for better statistics we
>> > need to run as many batches as possible.I suppose that the statistical
>> > deviation as calculated by code results from the distribution of average
>> > values of each batch.I would appreciate any comments and suggestions on
>> > this.
>> > Thank you
>> >
>> > On Tue, Jun 21, 2011 at 3:16 PM, mir inamul haq jeri<mirinamulhaq_at_gmail.com
>> >> wrote:
>> >
>> >> Thank you for your suggestion.
>> >> Now the problem is that i am getting the usrbin errors only as 99% and 0%
>> >> ir-respective of the number of particles that i run.i have run the same file
>> >> previously when i was getting only few percent of errors.Although i tried it
>> >> for the same number of particles as well as i had done previously when i was
>> >> getting only 6-10% error, but now i am getting only 99% and 0%.since the
>> >> values of yield/stars are different and the particle fluences are also
>> >> different in different regions(as seen from usrbin) i think there is some
>> >> error done by the code in calculating the errors.
>> >> I will be looking forward for your suggestions
>> >> Thank you
>>
>
>

```--
Alberto Fasso`
SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
Phone: (1 650) 926 4762   Fax: (1 650) 926 3569
fasso_at_slac.stanford.edu
```
Received on Mon Jun 27 2011 - 16:22:51 CEST

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