Re: gStyle->SetErrorX(dx)

When creating a TGraphErrors, TGraphAsymmErrors, you can give a null pointer as argument for
the array of errors along x or/and y. In this case, the errors will be taken as being null.
You do not need to create yourself an array filled with 0s.

Rene Brun

Olivier Couet wrote:
> Yes by definition, if you use TGraphAsymmErrors the erros should be
> provided.
> If you do not want to use errors use TGraph instead.
> There is nothing to improve here.
>
> -----Original Message-----
> From: Alexander Mann [mailto:amann_at_uni-goettingen.de]
> Sent: Wednesday, June 02, 2010 10:30 AM
> To: Olivier Couet
> Cc: roottalk_at_root.cern.ch
> Subject: Re: [ROOT] gStyle->SetErrorX(dx)
>
>
> So if I only want to have the y errors drawn using TGraphAsymmErrors, I
> always have to provide an additional array with 0s. Maybe this is sth.
> that could be improved in future releases :)
>
> cu,
> Alexander
>
>
> Am 02.06.2010 10:27, schrieb Olivier Couet:
>
>> gStyle->SetErrorX(dx) works for histogram. Here you draw a
>> TGraphAsymmErrors.
>> gStyle->SetErrorX(dx) as no effect on TGraphAsymmErrors.
>> If one use TGraphAsymmErrors it is assume it is to the errors.
>> The graph without errors is TGraph.
>>
>> -----Original Message-----
>> From: Alexander Mann [mailto:amann_at_uni-goettingen.de]
>> Sent: Wednesday, June 02, 2010 10:24 AM
>> To: Olivier Couet
>> Cc: roottalk_at_root.cern.ch
>> Subject: Re: [ROOT] gStyle->SetErrorX(dx)
>>
>>
>> Hi,
>>
>> so what's wrong with this code then:
>>
>> {
>>
>> gStyle->SetErrorX(0.0);
>>
>> h1 = new TH1F("h1", "h1", 2, -0.5, 1.5);
>> h2 = new TH1F("h2", "h2", 2, -0.5, 1.5);
>>
>> h1->Fill(0);
>> h2->Fill(0);
>> h2->Fill(0);
>> h2->Fill(1);
>>
>> h = new TGraphAsymmErrors(h1, h2);
>>
>> h->Draw("AL");
>>
>> }
>>
>> Does draw x error bars.
>>
>> Is there a way to disable those without using an additional array?
>>
>> cu,
>> Alexander
>>
>>
>> Am 02.06.2010 10:05, schrieb Olivier Couet:
>>
>>> This setting dx=0 in gStyle->SetErrorX(dx) remove the errors bar
>>>
>> display
>>
>>> along X.
>>> As it is explain in the doc.
>>>
>>> -----Original Message-----
>>> From: owner-roottalk_at_root.cern.ch
>>>
> [mailto:owner-roottalk_at_root.cern.ch]
>
>>> On Behalf Of Alexander Mann
>>> Sent: Tuesday, June 01, 2010 7:38 PM
>>> To: roottalk_at_root.cern.ch
>>> Subject: [ROOT] gStyle->SetErrorX(dx)
>>>
>>> Hi,
>>>
>>> the documentation http://root.cern.ch/root/html/TGraphPainter.html
>>>
>> says:
>>
>>> "gStyle->SetErrorX(dx) controls the size of the error along x. dx = 0
>>> removes the error along x."
>>>
>>> Does this method to get rid of the x-error bars work?
>>>
>>> cu,
>>> Alexander
>>>
>>>
>
>
Received on Wed Jun 02 2010 - 10:37:07 CEST