Create new TTree but get unexpected values

[Enki]

I create two TTree in one root file and assign some branches for trees.

myfile = ROOT.TFile.Open("3j3b.root","RECREATE")
mytree_sig = ROOT.TTree("sig","Signal")
mytree_bkg = ROOT.TTree("bkg","Background")

topFs = array.array('i',[0])
topFb = array.array('i',[0])
mytree_sig.Branch("jet_GBHInit_topHadronOriginFlag",topFs,"jet_GBHInit_topHadronOriginFlag_sig/I")
mytree_bkg.Branch("jet_GBHInit_topHadronOriginFlag",topFb,"jet_GBHInit_topHadronOriginFlag_bkg/I")
# I skipped codes of other branches that work well

for k in range(10000):
    topFb[0] = origin[k]
    topFs[0] = origin[k]
    # Here origin is a list of integers
    mytree_sig.Fill()
    mytree_bkg.Fill()
mytree_sig.SetDirectory(0)
mytree_bkg.SetDirectory(0)

myfile.cd()
mytree_sig.Write()
mytree_bkg.Write()
myfile.Close()

However, I finally got four TTree (two repeated trees) and weird values (should be integers) for the branch.

)
Does anyone know the reasons for them? Thank you in advance!

Happy Holiday!

[dastudillo]

If in your code above I replace origin[k] to just k I get the expected:

root [2] sig->Scan("jet_GBHInit_topHadronOriginFlag_sig")
************************
*    Row   * jet_GBHIn *
************************
*        0 *         0 *
*        1 *         1 *
*        2 *         2 *
*        3 *         3 *
*        4 *         4 *
*        5 *         5 *
*        6 *         6 *
*        7 *         7 *
*        8 *         8 *
*        9 *         9 *
*       10 *        10 *
*       11 *        11 *
*       12 *        12 *
*       13 *        13 *
*       14 *        14 *
*       15 *        15 *
*       16 *        16 *
*       17 *        17 *
*       18 *        18 *
*       19 *        19 *
*       20 *        20 *

So, check your values in origin[k]; if they are ok, try running only the lines in your example above and if those run well, then the problem should be in the lines you didn’t show above.

[Wile_E_Coyote]

You’d better use the python array type code 'l' to define the ROOT TTree fundamental type "/I" (Int_t).

[Enki]

I print origin[k] just before writing them and nothing looks wrong.

Using ‘l’ instead keeps most values as integers, although some still are recorded as float values (but a different value!). It meets requirements of program anyway, so thank you!

[Wile_E_Coyote]

Attach the output of: sig->Print(); bkg->Print();

[Enki]

Here I should have some ‘-99’ instead of ‘1.844e19’.
I noticed that ‘jet_GBHInit_topHadronOriginFlag’ has different basket number from other branches. Could it be a problem?

[Wile_E_Coyote]

You have plenty "/F" (a 32 bit floating point Float_t) branches, one "/l" (a 64 bit unsigned integer ULong64_t) branch, and no any "/I" (a 32 bit signed integer Int_t) branches.

For all your branches, you need to match the ROOT TTree fundamental type and the python array type code.

[Enki]

The first 15 branches are expected to be filled by float values, so I use "/F" for them. Only the last branch is expected to be filled by integers. I used "/I" initially and it returned weird output. Didn’t you suggest to use "/l" instead of "/I" ?

[Wile_E_Coyote]

Either:
b = array.array('l', [0]); t.Branch("b", b, "b/I")
or:
b = array.array('Q', [0]); t.Branch("b", b, "b/l")