CERN ROOT 使用事件标头制作树
我需要制作一棵带有事件标题的树。我从一个 ROOT 文件读入两个 ntuples。每个 ntuples 都具有以下格式：
Index Event SubEvent Characteristic1 Characteristic2 ....
1 1 1 322 234
2 1 2 453 324
3 1 3 ... ...
. . . ... ...
. . . ... ...
100 1 100 ... ...
101 2 1 ... ...
102 2 2 ... ...
. . . ... ...
. . . ... ...
. . . ... ...
207 2 107 ... ...
208 3 1 ... ...
209 3 2 ... ...
依此类推，索引运行到大约 200 万个。
我用来创建 ntuples 的格式：
TNtuple *tp = new TNtuple("tp","tp","x:y:z");
TNtuple *tn = new TNtuple("tn","tn","x:y:z");
for(Int_t n = 0; n < nEvents; n++) {
inTree->GetEntry(n);
Int_t nTracks = trackArray->GetEntries();
for(Int_t i = 0; i < nTracks; i++) {
Track* trackData = (Track*)trackArray->At(i);
if(trackData->fCharge == 1)
tp->Fill(trackData->x,trackData->y,trackData->z);
if(trackData->fCharge == -1)
tn->Fill(trackData->x,trackData->y,trackData->z);
}
}
但是，对于 ntuples，我遇到的问题是我想要对其进行的分析变得极其耗时。我希望我的数据结构与我正在读取的数据相同，即一棵有两个分支的树（对于我的两个“文件”），每个分支都包含一个偶数标头，以便我可以循环遍历一个中的事件文件，然后仅针对相同事件在第二个文件上嵌套循环。与上一个问题相关。< /a>
我没有如何构造原始文件的代码，这使得上述写入数据的方式成为可能。
I need to make a Tree with event headers. I read from a ROOT file into two ntuples. Each of these ntuples had the following format:
Index Event SubEvent Characteristic1 Characteristic2 ....
1 1 1 322 234
2 1 2 453 324
3 1 3 ... ...
. . . ... ...
. . . ... ...
100 1 100 ... ...
101 2 1 ... ...
102 2 2 ... ...
. . . ... ...
. . . ... ...
. . . ... ...
207 2 107 ... ...
208 3 1 ... ...
209 3 2 ... ...
and so on, the index runs till about two million.
The format I used to create the ntuples:
TNtuple *tp = new TNtuple("tp","tp","x:y:z");
TNtuple *tn = new TNtuple("tn","tn","x:y:z");
for(Int_t n = 0; n < nEvents; n++) {
inTree->GetEntry(n);
Int_t nTracks = trackArray->GetEntries();
for(Int_t i = 0; i < nTracks; i++) {
Track* trackData = (Track*)trackArray->At(i);
if(trackData->fCharge == 1)
tp->Fill(trackData->x,trackData->y,trackData->z);
if(trackData->fCharge == -1)
tn->Fill(trackData->x,trackData->y,trackData->z);
}
}
However, with ntuples I have the problem that the analysis that I want to do on it becomes impossibly time consuming. I would like to have my data structured in the same way as the data I am reading, i.e a tree with two braches (for my two "files") and each containing an even header, so that I can loop over the events in one file and subsequently nest a loop over the second file only for the same events. Related to previous question.
I do not have the code for how the original file was constructed, which allowed the above way of writing data possible.
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两百万并不算多。
if改为else ifTwo millions is not so much.
iftoelse if