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130.92.139.58 at 09:08, 30 August 2007

2007-08-30T09:08:47Z

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* To "turn off" the '''gray background''': gROOT->SetStyle("Plain"); (make sure to #include <TROOT.h> in compiled applications otherwise compiler won't know what gROOT is)
* To '''keep title from being displayed''': gStyle -> SetOptTitle(kFALSE);
* To '''keep statistics box from being displayed''': gStyle -> SetOptStat(kFALSE);
* To change '''histogram line width''' (default = 1): histo -> SetLineWidth(2);
* '''Line style''' (0: solid; 1:dotted; 2:dashed 3:dot-dash): histo -> SetLineStyle(3);
* To change '''marker style''': histo -> SetMarkerStyle(23);
* To change '''marker colour''': histo -> SetMarkerColor();
* To '''scale a histogram''': histo -> Scale( float scale_factor);
* To '''add labels''' to the x-axis of a histogram: histo -> GetXaxis() -> SetTitle("#sqrt{s} (GeV)");
* Changing the '''size of the axis title''': histo -> GetXaxis() -> SetTitleSize(0.048);
* To '''move the title''' closer/farther away from the plot: histo -> GetXaxis() -> SetTitleOffset(1.4); // arg is multiplicative factor.
* '''Axis labels''' if you have a function: funcn -> GetHistogram() -> GetXaxis() -> SetTitle("#sqrt{s} (GeV)");
* '''Axis labels''' if you have a graph: graph -> GetHistogram() -> GetXaxis() -> SetTitle("#sqrt{s} (GeV)"); for the y-axis, replace GetXaxis() with GetYaxis().
* '''Change color palette''' on histogram: gStyle->SetPalette(8,NULL);

Sometimes making a TGraph, data is plotted but you don't like the '''ranges on the axes''':
* Step 1) Make a canvas as usual (eg. mycanvas)
* Step 2) TH1F* histo = mycanvas -> DrawFrame(lowx, lowy, hix, hiy); (DrawFrame returns a pointer to a TH1F object)
* Step 3) Label axes with histogram pointer: histo -> GetXaxis() -> SetTitle("#sqrt{s} (GeV)");
* Step 4) Draw graph (do not use the "A" option as DrawFrame has drawn the axes for you already): graph -> Draw("P*");

How to '''fit a graph''' with an arbitrary function:
* Create a function with parameters. Here, they are [0] and [1].
* TF1* f90 = new TF1("f90", "[0]+[1]/x", 1., 40.);
* graph -> Fit (f90, "", "", 4., 40.);

'''Filling Histograms''': It's a really good idea to set the fill style as well as the color.
* eg. histo -> SetFillColor(7);
* hist0 -> SetFillStyle(1001); // This is for a solid fill.

Sometimes drawing your histogram or whatever, you find it doesn't fit on the canvas. To give the margins a little more room for things to fit properly, do the following:
* canvas -> SetRightMargin(0.15); (the default canvas has this set at 0.1, so if you want bigger, you need to put in a value of >0.1.) (also comes in Left, Top, abd Bottom flavours)

To make quantities displayed in the axis use scientific notation:
* TGaxis::SetMaxDigits(3);

Plots with ROOT - Revision history

Lhep: 1 revision imported

130.92.139.58 at 09:08, 30 August 2007