Hi…
I have a TTree, that has following structure
root [3] ImageTree->Print()
******************************************************************************
*Tree :ImageTree : Focal Images *
*Entries : 1000 : Total = 776003727 bytes File Size = 42963802 *
* : : Tree compression factor = 18.08 *
******************************************************************************
*Branch :FocalImage01 *
*Entries : 1000 : BranchElement (see below) *
*............................................................................*
*Br 0 :fUniqueID : UInt_t *
*Entries : 1000 : Total Size= 4656 bytes File Size = 234 *
*Baskets : 2 : Basket Size= 51200 bytes Compression= 17.79 *
*............................................................................*
*Br 1 :fBits : UInt_t *
*Entries : 1000 : Total Size= 8648 bytes File Size = 1566 *
*Baskets : 2 : Basket Size= 51200 bytes Compression= 5.22 *
*............................................................................*
*Br 2 :bunches : Int_t *
*Entries : 1000 : Total Size= 4644 bytes File Size = 2263 *
*Baskets : 2 : Basket Size= 51200 bytes Compression= 1.84 *
*............................................................................*
*Br 3 :photons : Double_t *
*Entries : 1000 : Total Size= 8644 bytes File Size = 5753 *
*Baskets : 2 : Basket Size= 51200 bytes Compression= 1.42 *
*............................................................................*
*Br 4 :lasttoa : Float_t *
*Entries : 1000 : Total Size= 4644 bytes File Size = 3805 *
*Baskets : 2 : Basket Size= 51200 bytes Compression= 1.09 *
*............................................................................*
*Br 5 :firsttoa : Float_t *
*Entries : 1000 : Total Size= 4650 bytes File Size = 3664 *
*Baskets : 2 : Basket Size= 51200 bytes Compression= 1.14 *
*............................................................................*
*Br 6 :max_csk_bunches : UInt_t *
*Entries : 1000 : Total Size= 4692 bytes File Size = 256 *
*Baskets : 2 : Basket Size= 51200 bytes Compression= 16.30 *
*............................................................................*
*Br 7 :ptrFocalBunch : Int_t ptrFocalBunch_ *
*Entries : 1000 : Total Size= 157826 bytes File Size = 252 *
*Baskets : 2 : Basket Size= 32000 bytes Compression= 16.55 *
*............................................................................*
*Br 8 :ptrFocalBunch.fUniqueID : UInt_t fUniqueID[ptrFocalBunch_] *
*Entries : 1000 : Total Size= 100106183 bytes File Size = 549252 *
*Baskets : 827 : Basket Size= 8256000 bytes Compression= 182.23 *
*............................................................................*
*Br 9 :ptrFocalBunch.fBits : UInt_t fBits[ptrFocalBunch_] *
*Entries : 1000 : Total Size= 100102859 bytes File Size = 597336 *
*Baskets : 827 : Basket Size= 8256000 bytes Compression= 167.55 *
*............................................................................*
*Br 10 :ptrFocalBunch.x : Float_t x[ptrFocalBunch_] *
*Entries : 1000 : Total Size= 100099535 bytes File Size = 10497276 *
*Baskets : 827 : Basket Size= 8255488 bytes Compression= 9.53 *
*............................................................................*
*Br 11 :ptrFocalBunch.y : Float_t y[ptrFocalBunch_] *
*Entries : 1000 : Total Size= 100099535 bytes File Size = 10476949 *
*Baskets : 827 : Basket Size= 8255488 bytes Compression= 9.55 *
*............................................................................*
*Br 12 :ptrFocalBunch.ctime : Float_t ctime[ptrFocalBunch_] *
*Entries : 1000 : Total Size= 100102859 bytes File Size = 9633472 *
*Baskets : 827 : Basket Size= 8256000 bytes Compression= 10.39 *
*............................................................................*
*Br 13 :ptrFocalBunch.photons : Float_t photons[ptrFocalBunch_] *
*Entries : 1000 : Total Size= 100104521 bytes File Size = 4630539 *
*Baskets : 827 : Basket Size= 8256000 bytes Compression= 21.61 *
*............................................................................*
*Br 14 :ptrFocalBunch.wvlength : Float_t wvlength[ptrFocalBunch_] *
*Entries : 1000 : Total Size= 100105352 bytes File Size = 5935059 *
*Baskets : 827 : Basket Size= 8256000 bytes Compression= 16.86 *
*............................................................................*
*Br 15 :ptrFocalBunch.ipix : Short_t ipix[ptrFocalBunch_] *
*Entries : 1000 : Total Size= 50102028 bytes File Size = 335719 *
*Baskets : 827 : Basket Size= 4131840 bytes Compression= 149.19 *
*............................................................................*
*Br 16 :ptrFocalBunch.isnoise : Bool_t isnoise[ptrFocalBunch_] *
*Entries : 1000 : Total Size= 25104521 bytes File Size = 225879 *
*Baskets : 827 : Basket Size= 2070528 bytes Compression= 111.07 *
*............................................................................*
*Br 17 :CORSIKA_BUNCHES : nbunches/I *
*Entries : 1000 : Total Size= 4667 bytes File Size = 2332 *
*Baskets : 2 : Basket Size= 51200 bytes Compression= 1.79 *
*............................................................................*
*Br 18 :Event : uevent/i *
*Entries : 1000 : Total Size= 4631 bytes File Size = 1661 *
*Baskets : 2 : Basket Size= 51200 bytes Compression= 2.50 *
*............................................................................*
I want to read only 2 branches in one of analysis “ptrFocalBunch.ctime” and “ptrFocalBunch.ipix”. How to do that ?
Currently I am reading whole “FocalImage01” branch. How to avoid it ?