[tutorials] Rename and comment graphs tutorials

documentation/users-guide/Graphs.md

@@ -229,7 +229,7 @@ gStyle->SetEndErrorSize(np);
 The four parameters of **`TGraphErrors`** are: `X, Y` (as in
 **`TGraph`**), `X`-errors, and `Y`-errors - the size of the errors
 in the `x` and `y` direction. Next example is
-`$ROOTSYS/tutorials/graphs/gerrors.C.`
+`$ROOTSYS/tutorials/graphs/gr002_err_1gr.C.`
 
 ``` {.cpp}
 {
@@ -702,7 +702,7 @@ root[] gr5->Draw("ALP")
 ```
 
 For more graph examples see the scripts: `$ROOTSYS/tutorials` directory
-`graph.C`, `gerrors.C`, `zdemo.C`, and `gerrors2.C`.
+`gr001_basic.C`, `gr002_err_1gr.C`, `gr303_zdemo.C`, and `gr003_err_2gr.C`.
 
 ![A graph with axis titles](pictures/0300005D.png)
 

graf2d/gpad/src/TButton.cxx

@@ -68,8 +68,8 @@ void but() {
    but3->Draw();
 
 // Create last button with no name. Instead a graph is draw inside the button
-// Clicking on this button will invoke the macro $ROOTSYS/tutorials/graphs/graph.C
-   button = new TButton("",".x tutorials/graphs/graph.C",0.15,0.15,0.85,0.38);
+// Clicking on this button will invoke the macro $ROOTSYS/tutorials/graphs/gr001_basic.C
+   button = new TButton("",".x tutorials/graphs/gr001_basic.C",0.15,0.15,0.85,0.38);
    button->SetFillColor(42);
    button->Draw();
    button->SetEditable(kTRUE);

graf2d/gpad/src/TControlBar.cxx

@@ -47,7 +47,7 @@ will return the name of the last clicked button.
                  "A Simple Fitting Example");
    bar.AddButton("draw2dopt",        ".x hist/draw2dopt.C",
                  "Drawing Options for 2D Histograms");
-   bar.AddButton("graph",            ".x graphs/graph.C",
+   bar.AddButton("graph",            ".x graphs/gr001_basic.C",
                  "Examples of a simple graph");
    bar.AddButton("tornado",          ".x graphics/tornado.C",
                  "Examples of 3-D PolyMarkers");

graf2d/gviz/doc/index.md

@@ -2,5 +2,5 @@
 \ingroup Graphics2D
 \brief Interface to the graphing package `graphviz`
 
-- graphstruct.C is an example of the graphviz interface classes usage.
+- gr016_struct.C is an example of the graphviz interface classes usage.
 

graf2d/gviz/src/TGraphStruct.cxx

@@ -49,7 +49,7 @@ three classes:
     a TGraphStruct.
 
 Begin_Macro(source)
-../../../tutorials/graphs/graphstruct.C
+../../../tutorials/graphs/gr016_struct.C
 End_Macro
 
 A graph structure can be dumped into a "dot" file using DumpAsDotFile.

hist/hist/src/TGraphSmooth.cxx

@@ -30,7 +30,7 @@ ClassImp(TGraphSmooth);
 /** \class TGraphSmooth
     \ingroup Graphs
 A helper class to smooth TGraph.
-see examples in $ROOTSYS/tutorials/graphs/motorcycle.C and approx.C
+see examples in gr010_approx_smooth.C and gr015_smooth.C
 */
 
 TGraphSmooth::TGraphSmooth()

hist/hist/src/TGraphTime.cxx

@@ -24,7 +24,7 @@ ClassImp(TGraphTime);
 TGraphTime is used to draw a set of objects evolving with nsteps in time between tmin and tmax.
 Each time step has a new list of objects. This list can be identical to
 the list of objects in the previous steps, but with different attributes.
-see example of use in $ROOTSYS/tutorials/graphs/gtime.C
+See example of use in gr017_time.C
 */
 
 ////////////////////////////////////////////////////////////////////////////////

hist/hist/src/TMultiGraph.cxx

@@ -224,7 +224,7 @@ Automatic coloring according to the current palette is available as shown in the
 following example:
 
 Begin_Macro(source)
-../../../tutorials/graphs/multigraphpalettecolor.C
+../../../tutorials/graphs/gr105_multigraphpalettecolor.C
 End_Macro
 
 \anchor MG01f
@@ -324,7 +324,7 @@ overlap. The following example shows how to make them all visible.
 
 
 Begin_Macro(source)
-../../../tutorials/graphs/multigraph.C
+../../../tutorials/graphs/gr007_multigraph.C
 End_Macro
 
 \anchor MG03

hist/hist/src/TScatter.cxx

@@ -39,7 +39,7 @@ color map and the fourth on the marker size.
 The following example demonstrates how it works:
 
 Begin_Macro(source)
-../../../tutorials/graphs/scatter.C
+../../../tutorials/graphs/gr006_scatter.C
 End_Macro
 
 ### TScatter's plotting options

hist/histpainter/doc/index.md

@@ -4,8 +4,8 @@
 The histograms and graphs plotting options are described in details in the THistPainter and TGraphPainter classes.
 Some related  tutorials:
 
-  - graph.C: Using and drawing a simple TGraph.
-  - graph2derrorsfit.C: TGraph2D with errors drawing.
+  - gr001_basic.C: Using and drawing a simple TGraph.
+  - gr011_2Derrorsfit.C: TGraph2D with errors drawing.
   - h1draw.C: Drawing Options for 1D Histograms.
   - hbars.C: Demo of option bar with histograms.
   - hsimple.C: Simple drawing of a 1D Histograms.

hist/histpainter/src/TGraphPainter.cxx

@@ -211,7 +211,7 @@ case the line width number is interpreted as:
 The current fill area attributes are used to draw the hatched zone.
 
 Begin_Macro(source)
-../../../tutorials/graphs/exclusiongraph.C
+../../../tutorials/graphs/gr106_exclusiongraph.C
 End_Macro
 
 \anchor GrP3
@@ -527,11 +527,11 @@ is determined according to the number of objects having palette coloring in
 the current pad.
 
 Begin_Macro(source)
-../../../tutorials/graphs/graphpalettecolor.C
+../../../tutorials/graphs/gr104_palettecolor.C
 End_Macro
 
 Begin_Macro(source)
-../../../tutorials/graphs/multigraphpalettecolor.C
+../../../tutorials/graphs/gr105_multigraphpalettecolor.C
 End_Macro
 
 \anchor GrP6
@@ -630,18 +630,18 @@ graphically. Point will be highlighted as "point circle" (presented by
 marker object). Moreover, any highlight (change of point) emits signal
 `TCanvas::Highlighted()` which allows the user to react and call their own
 function. For a better understanding please see also the tutorials
-`$ROOTSYS/tutorials/graphs/hlGraph*.C` files.
+`$ROOTSYS/tutorials/graphs/gr*_highlight*.C` files.
 
 Highlight mode is switched on/off by `TGraph::SetHighlight()` function
 or interactively from `TGraph` context menu. `TGraph::IsHighlight()` to verify
 whether the highlight mode enabled or disabled, default it is disabled.
 
 ~~~ {.cpp}
-    root [0] .x $ROOTSYS/tutorials/graphs/gerrors2.C
+    root [0] .x $ROOTSYS/tutorials/graphs/gr003_err_2gr.C
     root [1] // try SetHighlight() interactively from TGraph context menu
 ~~~
 
-\image html hlgerrors2.gif "Highlight mode for graph"
+\image html hl_gr003_err_2gr.gif "Highlight mode for graph"
 
 See how it is used
 <a href="classTHistPainter.html#HP30a">highlight mode and user function</a>

test/stressGUI.cxx

@@ -2211,8 +2211,8 @@ void testControlBars()
    bar->AddButton("fit1",      ".x fit/fit1.C",         "A Simple Fitting Example");
    bar->AddButton("multifit",  ".x fit/multifit.C",     "Fitting in Subranges of Histograms");
    bar->AddButton("h1draw",    ".x hist/h1draw.C",      "Drawing Options for 1D Histograms");
-   bar->AddButton("graph",     ".x graphs/graph.C",     "Example of a Simple Graph");
-   bar->AddButton("gerrors",   ".x graphs/gerrors.C",   "Example of a Graph with Error Bars");
+   bar->AddButton("graph",     ".x graphs/gr001_graph.C", "Example of a Simple Graph");
+   bar->AddButton("gerrors",   ".x graphs/gr002_err_1gr.C", "Example of a Graph with Error Bars");
    bar->AddButton("tornado",   ".x graphics/tornado.C", "Examples of 3-D PolyMarkers");
    bar->AddButton("shapes",    ".x geom/shapes.C",      "The Geometry Shapes");
    bar->AddButton("geometry",  ".x geom/geometry.C",    "Creation of the NA49 Geometry File");

tutorials/CMakeLists.txt

@@ -101,7 +101,7 @@ if (NOT dataframe)
     # RDataFrame
     list(APPEND dataframe_veto dataframe/*.C dataframe/*.py)
     # RDataFrame tutorial in graphs
-    list(APPEND dataframe_veto graphs/timeSeriesFromCSV_TDF.C)
+    list(APPEND dataframe_veto graphs/gr109_timeSeriesFromCSV_TDF.C)
     # TMVA tutorials dependent on RDataFrame
     list(APPEND dataframe_veto tmva/tmva*.C)
     list(APPEND dataframe_veto tmva/TMVA_SOFIE_RDataFrame*.C)
@@ -244,7 +244,7 @@ if(NOT ROOT_opengl_FOUND)
 endif()
 
 if(NOT GRAPHVIZ_FOUND)
-  set(gviz_veto graphs/graphstruct.C)
+  set(gviz_veto graphs/gr016_struct.C)
 endif()
 
 if(NOT TBB_FOUND AND NOT builtin_tbb)
@@ -434,7 +434,7 @@ if(MSVC AND NOT llvm13_broken_tests)
     list(APPEND extra_veto
          dataframe/df007_snapshot.C
          graphics/earth.C
-         graphs/motorcycle.C
+         graphs/gr015_smooth.C
          v7/ntuple/ntpl001_staff.C)
   endif()
 endif()
@@ -504,8 +504,8 @@ set(returncode_1 fit/fit2a.C
                  graphics/earth.C
                  graphics/pavetext.C
                  graphics/tmathtext.C graphics/tmathtext2.C
-                 graphs/exclusiongraph.C
-                 graphs/graphstruct.C
+                 graphs/gr106_exclusiongraph.C
+                 graphs/gr016_struct.C
                  hist/ContourList.C
                  hist/hbars.C
                  hist/th2polyBoxes.C

tutorials/demos.C

@@ -28,8 +28,8 @@ void demos() {
    bar->AddButton("fit1",          ".x fit/fit1.C",           "A Simple Fitting Example");
    bar->AddButton("multifit",      ".x fit/multifit.C",       "Fitting in Subranges of Histograms");
    bar->AddButton("h1ReadAndDraw", ".x hist/h1ReadAndDraw.C", "Drawing Options for 1D Histograms");
-   bar->AddButton("graph",         ".x graphs/graph.C",       "Example of a Simple Graph");
-   bar->AddButton("gerrors",       ".x graphs/gerrors.C",     "Example of a Graph with Error Bars");
+   bar->AddButton("graph",         ".x graphs/gr001_basic.C", "Example of a Simple Graph");
+   bar->AddButton("gerrors",       ".x graphs/gr002_err_1gr.C",     "Example of a Graph with Error Bars");
    bar->AddButton("tornado",       ".x graphics/tornado.C",   "Examples of 3-D PolyMarkers");
    bar->AddButton("geometry",      ".x geom/rootgeom.C",      "Example of TGeoManager drawing");
    bar->AddButton("file",          ".x io/file.C",            "The ROOT File Format");

tutorials/graphs/data_basic.txt

@@ -0,0 +1,20 @@
+-3.000000	-0.989992
+-2.684211	-0.897212
+-2.368421	-0.715699
+-2.052632	-0.463406
+-1.736842	-0.165284
+-1.421053	0.149185
+-1.105263	0.448899
+-0.789474	0.704219
+-0.473684	0.889894
+-0.157895	0.987561
+0.157895	0.987561
+0.473684	0.889894
+0.789474	0.704219
+1.105263	0.448899
+1.421053	0.149185
+1.736842	-0.165284
+2.052632	-0.463406
+2.368421	-0.715699
+2.684211	-0.897212
+3.000000	-0.989992

tutorials/graphs/gr001_basic.C

@@ -0,0 +1,77 @@
+/// \file
+/// \ingroup tutorial_graphs
+/// \notebook
+///
+/// This tutorial demonstrates how to create simple graphs in ROOT. The example is divided into two sections:
+/// - The first section plots data generated from arrays.
+/// - The second section plots data read from a text file.
+///
+/// \macro_image
+/// \macro_code
+/// 
+/// \author Rene Brun
+
+#include<fstream> //Include the library for reading the data file
+
+void gr001_basic() {
+   TCanvas *c1 = new TCanvas("c1","Two simple graphs",200,10,700,500);
+
+   c1->Divide(2,1); //Dividing the canvas in subpads for distinguishing the two examples, [See documentation](https://root.cern/doc/master/classTCanvas.html)
+
+   //FIRST EXAMPLE (Available data)
+   c1->cd(1);
+
+   const Int_t n = 20; //Fill the arrays x and y with the data points
+   Double_t x[n], y[n];
+   for (Int_t i=0;i<n;i++) {
+     x[i] = i*0.1;
+     y[i] = 10*sin(x[i]+0.2);
+     printf(" i %i %f %f \n",i,x[i],y[i]);
+   }
+
+   TGraph *gr1 = new TGraph(n,x,y); //Create a TGraph object, storing the number of data n and the x, y variables
+
+   //Set the color, width and style for the markers and line
+   gr1->SetLineColor(2);
+   gr1->SetLineWidth(4);
+   gr1->SetMarkerColor(4);
+   gr1->SetMarkerStyle(21);
+   gr1->SetTitle("Graph from available data"); //Choose title for the graph
+   gr1->GetXaxis()->SetTitle("X title"); //Choose title for the axis
+   gr1->GetYaxis()->SetTitle("Y title");
+
+   //Uncomment the following line to set a custom range for the x-axis (respectivly for the y-axis):
+   //gr1->GetXaxis()->SetRangeUser(0, 1.8); 
+
+   gr1->Draw("ACP"); //"A" draw axes, "C" = draw a smooth line through the markers (optional) and "P" = draw markers for data points 
+   //Optional customization can be done on a ROOT interactive session
+
+
+   //SECOND EXAMPLE (Data stored in a text file)
+   c1->cd(2);
+
+   const Int_t m = 20; //Known number of data points in the file
+   Double_t w[m], z[m];
+
+   std::ifstream file("data_basic.txt"); // Open the data file
+
+   // Use a for loop to read the data
+   for (Int_t i = 0; i < m; i++) {
+       file >> w[i] >> z[i]; //Fill the arrays with the data from the file
+   }
+   file.close(); //Close the file after reading
+
+
+   TGraph *gr2 = new TGraph(m, w, z); //Create a TGraph object for the file data
+   gr2->SetLineColor(4);
+   gr2->SetLineWidth(2);
+   gr2->SetMarkerColor(2);
+   gr2->SetMarkerStyle(20);
+   gr2->SetTitle("Graph from data file");
+   gr2->GetXaxis()->SetTitle("W title");
+   gr2->GetYaxis()->SetTitle("Z title");
+
+
+   gr2->Draw("ACP");
+}
+

tutorials/graphs/gerrors.C → tutorials/graphs/gr002_err_1gr.C

@@ -1,28 +1,36 @@
 /// \file
 /// \ingroup tutorial_graphs
 /// \notebook -js
-/// Draw a graph with error bars
+/// Create and draw a graph with error bars. If more graphs are needed, see the
+/// [gr03_err2gr.C](https://root.cern/doc/master/gerrors2_8C.html) tutorial
+///
+/// See the [TGraphErrors documentation](https://root.cern/doc/master/classTGraphErrors.html)
 ///
 /// \macro_image
 /// \macro_code
-///
 /// \author Rene Brun
 
-void gerrors() {
+void gr002_err_1gr() {
    TCanvas *c1 = new TCanvas("c1","A Simple Graph with error bars",200,10,700,500);
 
    c1->SetGrid();
    c1->GetFrame()->SetBorderSize(12);
 
+   // We will use the constructor requiring: the number of points, arrays containing the x-and y-axis values, and arrays with the x- andy-axis errors
    const Int_t n = 10;
    Float_t x[n]  = {-0.22, 0.05, 0.25, 0.35, 0.5, 0.61,0.7,0.85,0.89,0.95};
    Float_t y[n]  = {1,2.9,5.6,7.4,9,9.6,8.7,6.3,4.5,1};
    Float_t ex[n] = {.05,.1,.07,.07,.04,.05,.06,.07,.08,.05};
    Float_t ey[n] = {.8,.7,.6,.5,.4,.4,.5,.6,.7,.8};
+
+   // If all x-axis errors should zero, just provide a single 0 in place of ex
    TGraphErrors *gr = new TGraphErrors(n,x,y,ex,ey);
+
    gr->SetTitle("TGraphErrors Example");
    gr->SetMarkerColor(4);
    gr->SetMarkerStyle(21);
+
+   // To draw in a new/empty canvas or pad, include the option "A" so that the axes are drawn (leave it out if the graph is to be drawn on top of an existing plot
    gr->Draw("ALP");
 
    c1->Update();