MadAnalysis 5

handling negative-weighted events in ma5

Asked by Hesham El Faham

Hi,

I am using ma5 to plot some observables from a reweighed .lhe event file (parton-level). MadAnalysis complains about negative weights and thus set all bins to zero.

As a first trial I commented the line in histogram.py that sets data to zero in case of negative weights, but I am wondering if there is a more decent way of doing so, perhaps via the command line. I am also not sure whether such a solution would lead to a correct interpretation of the plots.

Thanks!
Hesham

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Benjamin Fuks
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Best Benjamin Fuks (fuks) said : 		#1

Hi Hesham,

You need more statistics to get positive entries in those bins. I am afraid there is no other good solutions. Another one may be to change the line style for the negative entries and take the absolute values.

Regards,

Benjamin

> On 11 Dec 2019, at 10:08 , Hesham El Faham <email address hidden> wrote:
>
> New question #686930 on MadAnalysis 5:
> https://answers.launchpad.net/madanalysis5/+question/686930
>
> Hi,
>
> I am using ma5 to plot some observables from a reweighed .lhe event file (parton-level). MadAnalysis complains about negative weights and thus set all bins to zero.
>
> As a first trial I commented the line in histogram.py that sets data to zero in case of negative weights, but I am wondering if there is a more decent way of doing so, perhaps via the command line. I am also not sure whether such a solution would lead to a correct interpretation of the plots.
>
> Thanks!
> Hesham
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.

Revision history for this message
Hesham El Faham (helfaham) said : 		#2

Thanks Benjamin Fuks, that solved my question.