TPrincipal::MakeHistograms()

ROOT
1

Hi,

I found that tutorial principal.C (win + v5.14) create only one hist. “pca_e”, while the method MakeHistograms(), called in this script, must produce a bunch of histograms by default?

2

To get all other histograms, add option “D” when calling TPrincipal constructor in the tutorial principal.C, ie, change

TPrincipal* principal = new TPrincipal(n,"N"); to

TPrincipal* principal = new TPrincipal(n,"ND");
I have changed the version CVS head to specify this option.

Rene

3

Thanks the tutorial is OK now.

I wrote simple script using TTree::Principal for creating TPrincipal. In this case, again only one hist pca_e were produced?

Int_t mkpca(const char *name=“ptrn.root”)
{
gROOT->Reset();
TDirectory sys_dir=gDirectory;
const char inf=name;
TFile fin(inf,“READ”);
sys_dir->cd();
TTree *t=fin.Get(“t”);
TPrincipal *pca;

pca=t->Principal(“vo:v1:v2”);
pca->Print(“MSEV”);
pca->MakeHistograms();
TBrowser* b = new TBrowser(“principalBrowser”, pca);

return -1;
}

4

The default set of histograms created after replacing the line

pca=t->Principal(“vo:v1:v2”);

with

pca=t->Principal(“vo:v1:v2”,"","");

in this case the default options “np” of method Principal() are ignored?

5

Igor,

It is not that the options are ignored, you SET them to “” and not the default.
You should call:

pca=t->Principal("vo:v1:v2","","np");
Rene

6

Hi Rene,

Thanks for your help. There are still some behaviors that seems strange for me.

  1. When the “n” option switched on in tree::Principal, there is only one histogramm generated, and also the UserData vector is not filled?
  2. Once I ran the method MakePrincipal() several times, the obtained results for a feature vector and histograms changes depends on the number rans? i.e.

pca=t->Principal(“a:b:c”,"","");
pca->MakePrincipals();
pca->MakePrincipals();
pca->MakePrincipals();
pca->MakePrincipals();
pca->Print(“MSEV”);
pca->MakeHistograms();

Igor

7

[quote]1) When the “n” option switched on in tree::Principal, there is only one histogramm generated, and also the UserData vector is not filled?
[/quote]

As I said in my previous post, you have to specify the option “D” to get all histograms.

I cannot reproduce this problem. Could you post a small tar.gz file as attachment containing a small data file and a small script showing the problem?

Rene

8

Sorry, the problem is appeare only when the TPrincipal created via tree interface by i.e. tree::Principal(“a:b:c”,“”,“ND”), while in the tutorial, where TPrincipal created directly, “D” option is working.

Just put in the tutorial the sequence of principal->MakePrincipals() calls and compare produced eigenvalues and histograms in the case of one call and two calls. Then you will find the differences

  
  // Do the actual analysis
  principal->MakePrincipals();
  principal->MakePrincipals();

igor

9

I changed the tutorial principal.C so it create TPrincipal via tree interface
principal.C (3.16 KB)