Hi Suhaili, Your question is very clear, and you're wright you need a .C file to analyse your results. Like you can see in the .C file in the benchmarkPET, this is C++ code based on the different ROOT classes. ROOT use this code to access your .root file and every data it contains. If you want complete documentation on how to use root, you can see the official documentation available on the web site but 500 pages are usually dissuasive ... The better thing to do is to look at the benchmark.C and see how it is made, most of people proceeds like that, and it is not too complicated especially if you already know C or C++. Good luck and if you don't succeed, don't hesitate to ask more precise questions. Simon <div>2007/5/28, Suhaili Zakaria <<a href="mailto:suhailiz@gmail.com">suhailiz@gmail.com</a>>:<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Hi, I have run benchmark files, and it seems to have no problem Now I run my own macro file, and got output.root file. How do I want to analyse it? As I understand it, there should also be output.C file? Is there any modification I should do? Hope that the question is clear. Many thanks for your reply, S _______________________________________________ Gate-users mailing list <a onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:Gate-users@lists.healthgrid.org">Gate-users@lists.healthgrid.org </a> <a onclick="return top.js.OpenExtLink(window,event,this)" href="http://lists.healthgrid.org/mailman/listinfo/gate-users" target="_blank">http://lists.healthgrid.org/mailman/listinfo/gate-users</a> </blockquote> </div>