FEDRA How To

• Some tips making Plots with ROOT.

• How to invert an affine transformation:

 - EdbAffine2D myaff
 - myaff.Set(float a11, float a12, float a21, float a22, float b1, float b2)
 - myaff.Invert()
 - myaff.Print()

• How to merge root files

 - TChain *chain=new TChain("couples");
 - chain->AddFile("myfile_1");
 - chain->AddFile("myfile_2");
 - chain->AddFile("...");
 - chain->Merge("my_output_file");
 - chain->~TChain();