Re: Creating Branches

From: Rene Brun (Rene.Brun@cern.ch)
Date: Thu Jun 26 1997 - 14:40:45 MEST


Maarten Bruinsma wrote:
> 
> Dear fellow ROOT users,
> 
> I just made my first TTree, but when compiling I keep getting a parse
> error. I have tried several things, as it seems there are many ways to
> create branches, but alas, all in vain. Could anyone tell me what's wrong
> with the following?
> 
> TROOT simple("simple","Test of histogramming and I/O");
> TFile hfile("mijnhistos.root","RECREATE","ROOT with all info on muons");
> 
> typedef struct {Float_t x,y,z;} POINT;
> POINT begin_vertex;
> static POINT end_vertex;
> static POINT momentum;
> static Int_t mother;
> static Float_t p;
> static Float_t pt;
> static Float_t track_length;
> 
> // this tree contain momenta etc. of several types of muons
> 
> TTree *muontree = new TTree("muontree","Data for all muons");
> 
> muontree->Branch("Momentum",&momentum,"Px:Py:Pz");
> muontree->Branch("Begin_Vertex",&begin_vertex,"Xvert:Yvert:Zvert");
> muontree->Branch("EndVertex".&end_vertex,"Xvert2:Yvert2:Zvert2");
> muontree->Branch("Tracklength",&track_length,"Tracklength");
> muontree->Branch("P",&p,"P");
> muontree->Branch("Pt",&pt,"Pt");
> muontree->Branch("Mother",&mother,"Mother/I");
> 
> I get a parse error at the line creating the first branch.
> 
> Thanks in advance,
> 

 Maarten,
You have a typing mistake in the line creating the 3rd branch (dot instead of comma).
This line should be:

    muontree->Branch("EndVertex",&end_vertex,"Xvert2:Yvert2:Zvert2");

If you make this change, your program will work.
 muontree->Print() will produce:
root [7] muontree->Print()
************************************************************************************
*Tree    :muontree  : Data for all muons                                           *
*Entries :        0 : Total  Size =         0 bytes  File  Size =          0 bytes *
*        :          : Tree compression factor =   1.00                             *
************************************************************************************
*Branch  :Momentum  : Px:Py:Pz                                                     *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 bytes *
*Baskets :        0 : Basket Size =     32000 bytes  EvOffsetLen=          0       *
*        :          : Branch compression factor =   1.00                           *
*..................................................................................*
*Branch  :Begin_Vertex : Xvert:Yvert:Zvert                                            *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 bytes *
*Baskets :        0 : Basket Size =     32000 bytes  EvOffsetLen=          0       *
*        :          : Branch compression factor =   1.00                           *
*..................................................................................*
*Branch  :EndVertex : Xvert2:Yvert2:Zvert2                                         *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 bytes *
*Baskets :        0 : Basket Size =     32000 bytes  EvOffsetLen=          0       *
*        :          : Branch compression factor =   1.00                           *
*..................................................................................*
*Branch  :Tracklength : Tracklength                                                  *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 bytes *
*Baskets :        0 : Basket Size =     32000 bytes  EvOffsetLen=          0       *
*        :          : Branch compression factor =   1.00                           *
*..................................................................................*
*Branch  :P         : P                                                            *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 bytes *
*Baskets :        0 : Basket Size =     32000 bytes  EvOffsetLen=          0       *
*        :          : Branch compression factor =   1.00                           *
*..................................................................................*
*Branch  :Pt        : Pt                                                           *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 bytes *
*Baskets :        0 : Basket Size =     32000 bytes  EvOffsetLen=          0       *
*        :          : Branch compression factor =   1.00                           *
*..................................................................................*
*Branch  :Mother    : Mother/I                                                     *
*Entries :        0 : Total  Size =         0 bytes  File Size  =          0 bytes *
*Baskets :        0 : Basket Size =     32000 bytes  EvOffsetLen=          0       *
*        :          : Branch compression factor =   1.00                           *
*..................................................................................*


Rene Brun



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