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+ | |||
+ | ===== Pitfalls ===== | ||
+ | |||
+ | ==== Unable to add to existing histograms ==== | ||
+ | Adding data to an existing histogram will fail, if any file was opened after creating the histogram! | ||
+ | TTree:: | ||
+ | |||
+ | To avoid this make sure to load the input files before you create any histograms or | ||
+ | create a storage file and switch back there after opening any files: | ||
+ | <code c++> | ||
+ | TFile tmp(" | ||
+ | float bins[] = {0, 10, 20, 40, 80}; | ||
+ | TH1F myhist(" | ||
+ | |||
+ | TFile file(" | ||
+ | TTree *tree = file.Get(" | ||
+ | |||
+ | tmp.cd() | ||
+ | tree-> | ||
+ | </ | ||