TGraph from TF1 problem


I am having difficulties with creation of TGraph object based on TF1 object using constructor:
TGraph(TF1 *fun, Option_t *option) from TGraph class.

Problem is with specifying range: in my case the minimum specified for TF1 object doesn’t seem to effect lower range for the created TGraph object (see the attached script). Is there a problem with TGraph constructor or am I doing something wrong? I am using root 4.04!

Test.C (1.41 KB)

By default the graph is created with as many points as you have in TF1 via TF1::SetNpx. Default is 100.
In your case you would like to map the function using a log scale.
This would be an interesting option to support in the TF1/TGraph constructor.
Meanwhile increase the number of mapping points in your TF1 by calling, eg, func->SetNpx(10000);