TH1->FillRandom() do not work

ROOT
1

Dear you,

My ROOT version is: ROOT 5.28/00g (tags/v5-28-00g@40876, Sep 14 2011, 15:32:32 on win32) Debug

The TH1::void FillRandom(const char *fname, Int_t ntimes) do not work correctly when ‘fname’ is a TF1.

TF1 *f1 = new TF1("func1","1/sin(x)", 0, TMath::Pi()/2);
TH1F *hf1 = new TH1F("Rrand","T_rand", 1000, 0, 1.5);
hf1->FillRandom("func1",10000)

All of the entries in the result histogram ‘hf1’ is in the first bin, as showed in the following picture.

c1.gif696×472 6.22 KB


And the following code caused crash of ROOT, as showed in the next picture.

TF1 *f1 = new TF1("func1","1/sin(x)", 0, TMath::Pi()/2);
TH1F *hf1 = new TH1F("Rrand","T_rand", 10, 0, 10); //The bin size and axise range is deferent to the previous code
hf1->FillRandom("func1",10000)

It seems that the crash may be related to the ‘xaxise’ range and bin size of ‘hf1’.


Any help is appreciated!

2

Hi,

First thing I notice is that sin (0) = 0 and 1 / 0 is bad…

Cheers,
Charles

3

[quote=“cplager”]Hi,

First thing I notice is that sin (0) = 0 and 1 / 0 is bad…

Cheers,
Charles[/quote]

Dear cplager, thank you very much!
Just as your answer, that’s the problem.

Han