Loop over TVector

Veronika · February 23, 2016, 4:42pm

Hi,

I’m new to ROOT and I came across some behaviour I don’t understand. Maybe someone can explain to me:

I want to read some variables (one is a simple float, the others are x- and yvalue of a ROOT.TVector) stored in a tree, so I did the following:

data=[]
for entry in file.tree:
    data.append([entry.VectorVariable[0], entry.FloatVariable])

this seems to work but if I want to have the second entry of the vector in addition, like so:

for entry in file.tree:
    data.append([entry.VectorVariable[0], entry.VectorVariable[1], entry.FloatVariable])

this results in an index out of range.

Obviously I’m doing something wrong here, since even if I try to retrieve the whole TVector data[0] holds TVectors with the same xvalues and only the yvalues varying.

How to read the correct values for xvalue, yvalue and float for every event stored in the tree?

Dominique · February 23, 2016, 7:13pm

Need check size vector first, make sure has all data. Does “len(entry.VectorVariable)” has wanted 2 size always? If no, need provide sample .root file and script to help debug.

-Dom

Veronika · February 24, 2016, 10:24am

Hi Dom,
thanks for your quick reply. Indeed there are entries with len(vector)=1 … I should have checked first.
Sorry if I keep asking stupid questions but I still have some difficulties

here’s the tree.Print():

******************************************************************************
*Tree    :Data_SRAll: 0-lepton small ntuple                                  *
*Entries :   151369 : Total =       139562684 bytes  File  Size =   37854222 *
*        :          : Tree compression factor =   3.59                       *
******************************************************************************
*Br    0 :NTVars    : RunNumber/i:EventNumber/i:LumiBlockNumber/i:veto/i:    *
*         | eventWeight/F:pileupWeight/F:pileupWeightUp/F:pileupWeightDown/F:*
*         | genWeight/F:ttbarWeightHT/F:ttbarWeightPt2/F:ttbarAvgPt/F:       *
*         | WZweight/F:nJet/i:met/F:metPhi/F:dPhi/F:dPhiR/F:meffInc/F:       *
*         | hardproc/I:nBJet/I:nCJet/I:bTagWeight/F:bTagWeightBUp/F:         *
*         | bTagWeightBDown/F:bTagWeightCUp/F:bTagWeightCDown/F:             *
*         | bTagWeightLUp/F:bTagWeightLDown/F:cTagWeight/F:cTagWeightBUp/F:  *
*         | cTagWeightBDown/F:cTagWeightCUp/F:cTagWeightCDown/F:             *
*         | cTagWeightLUp/F:cTagWeightLDown/F:normWeight/F:normWeightUp/F:   *
*         | normWeightDown/F:cleaning/i:timing/F:jet1Emf/F:jet2Emf/F:        *
*         | jet1Chf/F:jet2Chf/F:pdfId1/I:pdfId2/I:tauN/i:tauJetBDTLoose/i:   *
*         | tauLooseN/i:tauMt/F:SherpaBugMET/F:dPhiBadTile/F:isNCBEvent/O    *
*Entries :   151369 : Total  Size=   32828784 bytes  File Size  =    8336751 *
*Baskets :      313 : Basket Size=     555008 bytes  Compression=   3.87     *
*............................................................................*
*Br    1 :jetPt     : vector<float>                                          *
*Entries :   151369 : Total  Size=    3666860 bytes  File Size  =    1941581 *
*Baskets :       53 : Basket Size=     174080 bytes  Compression=   1.82     *
*............................................................................*
*Br    2 :jetEta    : vector<float>                                          *
*Entries :   151369 : Total  Size=    3666919 bytes  File Size  =    2006645 *
*Baskets :       53 : Basket Size=     174080 bytes  Compression=   1.76     *
*............................................................................*
*Br    3 :jetPhi    : vector<float>                                          *
*Entries :   151369 : Total  Size=    3666919 bytes  File Size  =    2003904 *
*Baskets :       53 : Basket Size=     174080 bytes  Compression=   1.76     *
*............................................................................*
*Br    4 :jetM      : vector<float>                                          *
*Entries :   151369 : Total  Size=    3666801 bytes  File Size  =    1950585 *
*Baskets :       53 : Basket Size=     174080 bytes  Compression=   1.81     *
*............................................................................*
*Br    5 :jetBTag   : vector<float>                                          *
*Entries :   151369 : Total  Size=    3666978 bytes  File Size  =    1777931 *
*Baskets :       53 : Basket Size=     174080 bytes  Compression=   1.98     *
*............................................................................*
*Br    6 :jetFlav   : vector<int>                                            *
*Entries :   151369 : Total  Size=    3666978 bytes  File Size  =     539917 *
*Baskets :       53 : Basket Size=     174080 bytes  Compression=   6.54     *
*............................................................................*
*Br    7 :jetTagU   : vector<float>                                          *
*Entries :   151369 : Total  Size=    3666978 bytes  File Size  =     539706 *
*Baskets :       53 : Basket Size=     174080 bytes  Compression=   6.54     *
*............................................................................*
*Br    8 :jetTagB   : vector<float>                                          *
*Entries :   151369 : Total  Size=    3666978 bytes  File Size  =     539706 *
*Baskets :       53 : Basket Size=     174080 bytes  Compression=   6.54     *
*............................................................................*
*Br    9 :jetTagC   : vector<float>                                          *
*Entries :   151369 : Total  Size=    3666978 bytes  File Size  =     539706 *
*Baskets :       53 : Basket Size=     174080 bytes  Compression=   6.54     *
*............................................................................*
*Br   10 :jetFracSamplingMax : vector<float>                                 *
*Entries :   151369 : Total  Size=    3667810 bytes  File Size  =    1917979 *
*Baskets :       54 : Basket Size=     174080 bytes  Compression=   1.84     *
*............................................................................*
*Br   11 :jetFracSamplingMaxIndex : vector<float>                            *
*Entries :   151369 : Total  Size=    3668144 bytes  File Size  =     845146 *
*Baskets :       54 : Basket Size=     174080 bytes  Compression=   4.18     *
*............................................................................*
*Br   12 :tauPt     : vector<float>                                          *
*Entries :   151369 : Total  Size=    2170042 bytes  File Size  =     309365 *
*Baskets :       43 : Basket Size=     105984 bytes  Compression=   6.92     *
*............................................................................*
*Br   13 :tauEta    : vector<float>                                          *
*Entries :   151369 : Total  Size=    2170091 bytes  File Size  =     312774 *
*Baskets :       43 : Basket Size=     105984 bytes  Compression=   6.84     *
*............................................................................*
*Br   14 :tauPhi    : vector<float>                                          *
*Entries :   151369 : Total  Size=    2170091 bytes  File Size  =     312874 *
*Baskets :       43 : Basket Size=     105984 bytes  Compression=   6.84     *
*............................................................................*
*Br   15 :tauLooseSF : vector<float>                                         *
*Entries :   151369 : Total  Size=    2170301 bytes  File Size  =     283204 *
*Baskets :       43 : Basket Size=     105984 bytes  Compression=   7.56     *
*............................................................................*
*Br   16 :tauLooseSFStatUp : vector<float>                                   *
*Entries :   151369 : Total  Size=    2168625 bytes  File Size  =     283568 *
*Baskets :       43 : Basket Size=     106496 bytes  Compression=   7.55     *
*............................................................................*
*Br   17 :tauLooseSFStatDown : vector<float>                                 *
*Entries :   151369 : Total  Size=    2168723 bytes  File Size  =     283691 *
*Baskets :       43 : Basket Size=     106496 bytes  Compression=   7.55     *
*............................................................................*
*Br   18 :tauLooseSFSystUp : vector<float>                                   *
*Entries :   151369 : Total  Size=    2168625 bytes  File Size  =     283568 *
*Baskets :       43 : Basket Size=     106496 bytes  Compression=   7.55     *
*............................................................................*
*Br   19 :tauLooseSFSystDown : vector<float>                                 *
*Entries :   151369 : Total  Size=    2168723 bytes  File Size  =     283691 *
*Baskets :       43 : Basket Size=     106496 bytes  Compression=   7.55     *
*............................................................................*
*Br   20 :systWeights : vector<float>                                        *
*Entries :   151369 : Total  Size=    2738258 bytes  File Size  =     241533 *
*Baskets :       48 : Basket Size=     135680 bytes  Compression=  11.30     *
*............................................................................*
*Br   21 :btagSystWeights : vector<float>                                    *
*Entries :   151369 : Total  Size=    2738474 bytes  File Size  =     241755 *
*Baskets :       48 : Basket Size=     135680 bytes  Compression=  11.29     *
*............................................................................*
*Br   22 :NTReclusteringVars : NWcandidates/i:test/i:nJetsRecl/I             *
*Entries :   151369 : Total  Size=    2194116 bytes  File Size  =      10270 *
*Baskets :       19 : Basket Size=     555008 bytes  Compression= 177.04     *
*............................................................................*
*Br   23 :RTjets10SubJetIndeces : vector<vector<int> >                       *
*Entries :   151369 : Total  Size=    5010186 bytes  File Size  =     926806 *
*Baskets :       64 : Basket Size=     238080 bytes  Compression=   5.23     *
*............................................................................*
*Br   24 :RTjetPt   : vector<float>                                          *
*Entries :   151369 : Total  Size=    3472000 bytes  File Size  =    1733962 *
*Baskets :       52 : Basket Size=     164352 bytes  Compression=   1.92     *
*............................................................................*
*Br   25 :RTjetEta  : vector<float>                                          *
*Entries :   151369 : Total  Size=    3472058 bytes  File Size  =    1803220 *
*Baskets :       52 : Basket Size=     164352 bytes  Compression=   1.85     *
*............................................................................*
*Br   26 :RTjetPhi  : vector<float>                                          *
*Entries :   151369 : Total  Size=    3472058 bytes  File Size  =    1799591 *
*Baskets :       52 : Basket Size=     164352 bytes  Compression=   1.85     *
*............................................................................*
*Br   27 :RTjetM    : vector<float>                                          *
*Entries :   151369 : Total  Size=    3471902 bytes  File Size  =    1759581 *
*Baskets :       52 : Basket Size=     164352 bytes  Compression=   1.90     *
*............................................................................*
*Br   28 :ReclJetMass : vector<float>                                        *
*Entries :   151369 : Total  Size=    2152086 bytes  File Size  =     229454 *
*Baskets :       43 : Basket Size=     105472 bytes  Compression=   9.25     *
*............................................................................*
*Br   29 :ReclJetPt : vector<float>                                          *
*Entries :   151369 : Total  Size=    2151988 bytes  File Size  =     228630 *
*Baskets :       43 : Basket Size=     105472 bytes  Compression=   9.29     *
*............................................................................*
*Br   30 :ReclJetEta : vector<float>                                         *
*Entries :   151369 : Total  Size=    2152037 bytes  File Size  =     228566 *
*Baskets :       43 : Basket Size=     105472 bytes  Compression=   9.29     *
*............................................................................*
*Br   31 :ReclJetPhi : vector<float>                                         *
*Entries :   151369 : Total  Size=    2152037 bytes  File Size  =     228566 *
*Baskets :       43 : Basket Size=     105472 bytes  Compression=   9.29     *
*............................................................................*
*Br   32 :D2        : vector<float>                                          *
*Entries :   151369 : Total  Size=    2151645 bytes  File Size  =     228379 *
*Baskets :       43 : Basket Size=     105472 bytes  Compression=   9.29     *
*............................................................................*
*Br   33 :isWmedium : vector<bool>                                           *
*Entries :   151369 : Total  Size=    2151988 bytes  File Size  =     228630 *
*Baskets :       43 : Basket Size=     105472 bytes  Compression=   9.29     *
*............................................................................*
*Br   34 :isWtight  : vector<bool>                                           *
*Entries :   151369 : Total  Size=    2151939 bytes  File Size  =     228561 *
*Baskets :       43 : Basket Size=     105472 bytes  Compression=   9.29     *
*............................................................................*
*Br   35 :isZmedium : vector<bool>                                           *
*Entries :   151369 : Total  Size=    2151988 bytes  File Size  =     228630 *
*Baskets :       43 : Basket Size=     105472 bytes  Compression=   9.29     *
*............................................................................*
*Br   36 :isZtight  : vector<bool>                                           *
*Entries :   151369 : Total  Size=    2151939 bytes  File Size  =     228561 *
*Baskets :       43 : Basket Size=     105472 bytes  Compression=   9.29     *
*............................................................................*
*Br   37 :NTExtraVars : mettrack/F:mettrack_phi/F:mT2/F:mT2_noISR/F:Ap/F     *
*Entries :   151369 : Total  Size=    3101431 bytes  File Size  =    1965459 *
*Baskets :       32 : Basket Size=     555008 bytes  Compression=   1.54     *
*............................................................................*

the float variable is the met in NTVars and the vector is RTjetM
Is there a way to get all RTjetM Vectors independently of their length?
simply doing:

In [76]: tree
Out[76]: <ROOT.TTree object ("Data_SRAll") at 0x29928d0>

In [77]: data=[]        

In [78]: for event in tree:
   ....:     data.append(event.RTjetM)
   ....:

fills data with the very same vector

In [79]: data[0]
Out[79]: <ROOT.vector<float> object at 0x2f32020>

In [80]: data[10]
Out[80]: <ROOT.vector<float> object at 0x2f32020>

but on the other hand:

In [84]: data=[]

In [85]: for event in tree:
    data.append(event.RTjetM[0])
   ....:     

In [86]: data[0]
Out[86]: 10.932619094848633

In [87]: data[10]
Out[87]: 13.312379837036133

seems to get the first entry of all the vectors. Why is that?

pcanal · February 24, 2016, 2:44pm

[quote]seems to get the first entry of all the vectors. Why is that?[/quote]because this is literally what the code asks for … i.e. In [85]: for event in tree: data.append(event.RTjetM[0])says: for each entry in the TTree, add the first ([0]) element of the vector named ‘event.RTjetM’ into the python array named ‘data’ …

[quote]How to read the correct values for xvalue, yvalue and float for every event stored in the tree?[/quote]I am not sure what ’ xvalue, yvalue and float ’ refer to in your TTree. Could you me more specific?

Thanks,
Philippe.

Dominique · February 24, 2016, 4:52pm

So is not ROOT.TVector in file, but is ROOT.std.vector(‘float’). Is anyway not understand why need copy in list? Iter on std.vector itself fine (and use size correct!), is example:for val in event.RTjetM: print val
Now if really only want all value, no structure:for event in tree: data += event.RTjetM
-Dom

Veronika · February 24, 2016, 5:17pm

thanks again for your replies.
Sorry I was not specific enough, my question is why

for event in tree:
   ....:     data.append(event.RTjetM)

gives a list filled with equal vectors?

Dominique · February 24, 2016, 6:01pm

Is same object over over over: object insert is pointer insert (Python reference), not object copy. Is TTree use same address and is PyROOT recycle address (because faster and identity important). Can copy if want: use module copy or copy constructor.

-Dom

Veronika · February 25, 2016, 9:04am

I see, thanks again