overflow and underflow

Asked by Jae Hoon Jeong on 2019-08-15

I got some histogram lists. I show you this list.

 myHisto9__9->SetBinContent(0,20); <-underflow
   myHisto9__9->SetBinContent(1,34733);
   myHisto9__9->SetBinContent(2,77941);
   myHisto9__9->SetBinContent(3,110951);
   myHisto9__9->SetBinContent(4,132854);
   myHisto9__9->SetBinContent(5,143514);
   myHisto9__9->SetBinContent(6,143642);
   myHisto9__9->SetBinContent(7,132821);
   myHisto9__9->SetBinContent(8,110394);
   myHisto9__9->SetBinContent(9,78140);
   myHisto9__9->SetBinContent(10,34989);
   myHisto9__9->SetBinContent(11,1); <-overflow

I set the number of bins as 10 and range as 0~3.141592 and number of event as 1000000. that is, commands are 10 0 3.141592.
When I study about Histogram sample file. I saw that these values are under and overflow.
By the way, what's the meaning of overflow and underflow?? and Why is this values made?
And if there are these, is my setting wrong? And In order to remove over and underflow events, How should I do??
Please answer about it.

Question information

Language:
English Edit question
Status:
Answered
For:
MadAnalysis 5 Edit question
Assignee:
No assignee Edit question
Last query:
2019-08-20
Last reply:
2019-08-20
Benjamin Fuks (fuks) said : #1

Hi,

MadAnalysis 5 generates root files compliant with the root syntax. I recommend you to have a look to the root website for more information (everything is explained in great details in there). For the short version:
 - you required the generation of a histogram made of 10 bins. Therefore, MadAnalysis generated a root macro in which a histogram with 10 bins is filled (you can check the bin values in the provided snippet of code).
 - The "underflow" and "overflow" lines correspond to the underflow and overflow bins (so that 12 bins are filled in total, as visible from the snippet of code you pasted).
 - The values consist in what came out of the event file that has been analysed.

Regards,

Benjamin

> On 15 Aug 2019, at 07:32 , Jae Hoon Jeong <email address hidden> wrote:
>
> Question #682910 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/682910
>
> Description changed to:
> I got some histogram lists. I show you this list.
>
> myHisto9__9->SetBinContent(0,20); <-underflow
> myHisto9__9->SetBinContent(1,34733);
> myHisto9__9->SetBinContent(2,77941);
> myHisto9__9->SetBinContent(3,110951);
> myHisto9__9->SetBinContent(4,132854);
> myHisto9__9->SetBinContent(5,143514);
> myHisto9__9->SetBinContent(6,143642);
> myHisto9__9->SetBinContent(7,132821);
> myHisto9__9->SetBinContent(8,110394);
> myHisto9__9->SetBinContent(9,78140);
> myHisto9__9->SetBinContent(10,34989);
> myHisto9__9->SetBinContent(11,1); <-overflow
>
> I set the number of bins as 10 and range as 0~3.141592 and number of event as 1000000. that is, commands are 10 0 3.141592.
> When I study about Histogram sample file. I saw that these values are under and overflow.
> By the way, what's the meaning of overflow and underflow?? and Why is this values made?
> And if there are these, is my setting wrong? And In order to remove over and underflow events, How should I do??
> Please answer about it.
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.

Jae Hoon Jeong (jaehoon229) said : #2

Thank you so much. But what I really wonder is why overflow and underflow is made, even though I set 10 bin.
And please teach me the root cite about overflow and underflow more specifically. After reading your answer, I find
information of overflow and underflow in the root cite of Cern, but I couldn't find the information finally...

Thank you so much

Regards

Jae Hoon Jeong

Benjamin Fuks (fuks) said : #3

Hi,

This information is actually availalbe everywhere on the web… it is when one has histogram entries lying outside the selected x-axis range.

Cheers,

Benjamin

> On 20 Aug 2019, at 09:18 , Jae Hoon Jeong <email address hidden> wrote:
>
> Question #682910 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/682910
>
> Status: Answered => Open
>
> Jae Hoon Jeong is still having a problem:
> Thank you so much. But what I really wonder is why overflow and underflow is made, even though I set 10 bin.
> And please teach me the root cite about overflow and underflow more specifically. After reading your answer, I find
> information of overflow and underflow in the root cite of Cern, but I couldn't find the information finally...
>
> Thank you so much
>
> Regards
>
> Jae Hoon Jeong
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.

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