KADD 2022 Laboratorium 1 EN

Documentation

Documentation of the ROOT environment:

main page: https://root.cern.ch/
documentation of the development version (master): https://root.cern.ch/doc/master/
documentation of the stable version (6.22): https://root.cern/doc/v622/
documentation of the laboratory version (5.32.00): https://root.cern.ch/root/html532/ last version with the old C++ interpreter

1. Write a macro, which:

creates an object fun1 of type TF1 representing a sin(x) function (see class TMath)
creates an object fun2 of type TF1 representing a cos(x) function
creates a window with 4 panels (panel distribution 2x2) - see class TCanvas and method Divide
draws the fun1 object on panel 1, fun2 on panel 2, and two functions simultaneously on panel 3
changes the color of the line of function fun2 to blue - see method SetLineColor and class TColor

2. Let's imagine we throw a dice that is asymmetric. The table below summarizes the results:

Number of pips	1	2	3	4	5	6
Number of throws	2	1	5	4	10	12

We modify further the macro:

let's create a histogram (see class TH1D) by filling each bin (which corresponds to each dice facet) with values from the table (number of throws) - the histogram should be plotted on panel 4
create a plot, called graph (see class TGraph) according to values from the table.
change the style of graph points (see method SetMarkerStyle and class TAttMarker)
draw the graph in a separate window

Attention! In order to run ROOT environment on your student account in the laboratory, you have to add the following lines (if they were not added already) to the file $HOME/.bashrc (they could had been added during the PTI class):

 export ROOTSYS=/opt/root
 export PATH=$PATH:$ROOTSYS/bin
 export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROOTSYS/lib

the ROOT environment is installed separately on each computer - it is not available on the server
in the ROOT environment we write macros, which have extensions .c, .C, .cpp, or .cxx
a macro contains a C++ code interpreted line-by-line
in principle, we do not need to include any libraries
example 1:

{
    double x = 5;
    cout<<x<<endl;
}

int macro()
{
    double x = 5;
    cout<<x<<endl;
    return 1;
}

name of the macro must be the same as the name of the main function in the macro (in order to run it with the command .x macro.C)
macros can contain more functions - during the macro execution the one which will be run is that which name corresponds to the macro name (the equivalent of the main function in standard C++)

Plots: