Does TTree::Draw() support 2-dim arrays?

R. Holzmann (holzmann@axp101.gsi.de)
Thu, 24 Sep 1998 20:57:19 -1300


Dear ROOTers,

does TTree::Draw() support arrays of more than 1 dimension?
Also, what is the notation used to specify index ranges?

My problem is the following:

I have a tree generated with h2root from a PAW CWN tuple.
Here's the output of the PAW n/print command:

PAW> n/print 3011

******************************************************************
* Ntuple ID = 3011 Entries = 10 MDC11
******************************************************************
* Var numb * Type * Packing * Range * Block * Name *
******************************************************************
* 1 * U*4 * * * IEVT * IDEVT
* 1 * I*4 * * [0,100] * S1D1 * NHIT
* 2 * U*4 * 13 * [0,8000] * S1D1 * MDCTRK(NHIT)
* 3 * R*4 * * * S1D1 * MDCX(6,NHIT)
* 4 * R*4 * * * S1D1 * MDCY(6,NHIT)
* 5 * R*4 * * * S1D1 * MDCTHETA(6,NHIT)
* 6 * R*4 * * * S1D1 * MDCPHI(6,NHIT)
* 7 * R*4 * * * S1D1 * MDCTOF(6,NHIT)
******************************************************************
* Block * Entries * Unpacked * Packed * Packing Factor *
******************************************************************
* IEVT * 10 * 4 * 4 * 1.000 *
* S1D1 * 10 * 12404 * Var. * Variable *
* Total * --- * 12408 * Var. * Variable *
******************************************************************
* Blocks = 2 Variables = 8 Max. Columns = 3102 *
******************************************************************

and the corresponding h3011->Print() output is:

root [10] h3011->Print()
******************************************************************************
*Tree :h3011 : MDC11 *
*Entries : 10 : Total Size = 25608 bytes File Size = 25608 *
* : : Tree compression factor = 1.00 *
******************************************************************************
*Branch :Idevt : Idevt/i *
*Entries : 10 : Total Size = 0 bytes File Size = 0 *
*Baskets : 0 : Basket Size = 8000 bytes Compression= 1.00 *
*............................................................................*
*Branch :Nhit : Nhit/I *
*Entries : 10 : Total Size = 0 bytes File Size = 0 *
*Baskets : 0 : Basket Size = 8000 bytes Compression= 1.00 *
*............................................................................*
*Branch :Mdctrk : Mdctrk[Nhit]/i *
*Entries : 10 : Total Size = 0 bytes File Size = 0 *
*Baskets : 0 : Basket Size = 8000 bytes Compression= 1.00 *
*............................................................................*
*Branch :Mdcx : Mdcx[Nhit][6]/F *
*Entries : 10 : Total Size = 0 bytes File Size = 0 *
*Baskets : 0 : Basket Size = 8000 bytes Compression= 1.00 *
*............................................................................*
*Branch :Mdcy : Mdcy[Nhit][6]/F *
*Entries : 10 : Total Size = 0 bytes File Size = 0 *
*Baskets : 0 : Basket Size = 8000 bytes Compression= 1.00 *
*............................................................................*
*Branch :Mdctheta : Mdctheta[Nhit][6]/F *
*Entries : 10 : Total Size = 0 bytes File Size = 0 *
*Baskets : 0 : Basket Size = 8000 bytes Compression= 1.00 *
*............................................................................*
*Branch :Mdcphi : Mdcphi[Nhit][6]/F *
*Entries : 10 : Total Size = 0 bytes File Size = 0 *
*Baskets : 0 : Basket Size = 8000 bytes Compression= 1.00 *
*............................................................................*
*Branch :Mdctof : Mdctof[Nhit][6]/F *
*Entries : 10 : Total Size = 0 bytes File Size = 0 *
*Baskets : 0 : Basket Size = 8000 bytes Compression= 1.00 *
*............................................................................*

Now, in PAW I could do nice things on the 2dim arrays, like

PAW> n/plo 3011.mdcx(1,2)

and

PAW> n/plo 3011.mdcx(1,1:nhit)

or even select subranges

PAW> n/plo 3011.mdcx(1:3,nhit-10:nhit)

i.e. I had full control over BOTH indices!

How much of this can I do with the TTree::Draw() member function?

Thanks a lot for any help.

Romain Holzmann

p.s. Tom Moog from ANL posted a similar question quite some time ago, but no
answer has apparently been threaded.