Slow histogram drawing with option "PE" with rootlogon.C

I am drawing (many) fitted histograms with many points (over 5000 points). One thing I encountered is that it takes long time to draw the histograms with option “PE” but not “HIST”.
This happens only if I put ROOT.gROOT.Macro("rootlogon.C") .

Am I lefting out something in the rootlogon.C so it lead to this kind of situation ?

the rootlogon.C contents are as below:

 // Definition of new styles
 TStyle *MyStyle      = new TStyle("MyStyle","MyStyle");
 TStyle *MyStyle_work = new TStyle("MyStyle_Work","MyStyle_work");

 // Set the default parameters for style MyStyle
 MyStyle->SetCanvasBorderMode(0);     // Removes Canvas Border
 MyStyle->SetPadBorderMode(0);        // Removes Pad Border
 MyStyle->SetCanvasColor(0);          // Changes Canvas color to white
 MyStyle->SetPadColor(0);             // Changes Pad color to white
 MyStyle->SetStatColor(0);            // Changes Stats bg color to white
 MyStyle->SetTitleFillColor(0);       // Changes Title bg color to white

 MyStyle->SetFrameLineWidth(2);       // make frame pop 
 MyStyle->SetLabelSize(0.04,"xyz");   // increase size for redability
 MyStyle->SetTitleSize(0.04,"xyz");   // "
 MyStyle->SetLabelFont(62,"xyz");     // helvetica bold for redability
 MyStyle->SetTitleFont(62,"xyz");     // "

 MyStyle->SetPadTickX(1);             // Sets tic marks on both horizontal axes
 MyStyle->SetPadTickY(1);             // Sets tic marks on both vertical axes
 MyStyle->SetTickLength(0.02,"xyz"); // Sets tic length
 MyStyle->SetOptStat(0);              // Turns off Statistics display
 MyStyle->SetOptTitle(0);             // Turns off Title display
 MyStyle->SetHistLineWidth(2);        // Changes Histogram Line width
 MyStyle->SetFrameBorderMode(0);      // Removes the Frame Border
 MyStyle->SetCanvasDefH(600);         // Sets Default Canva Height
 MyStyle->SetCanvasDefW(900);         // Sets Default Canvas Width

 // The next for commands set the default margin size
 // n.b. the margins do not take axis labels into account! grr!!
 MyStyle->SetPadTopMargin(0.1);     // Set Margin Top
 MyStyle->SetPadRightMargin(0.1);   // Set Margin Right
 MyStyle->SetPadBottomMargin(0.1);    // Set Margin Bottom
 MyStyle->SetPadLeftMargin(0.1);     // Set Margin Left

 //make a nice palette
 int NRGBs = 7, NCont = 999;
 Double_t stops[7] = { 0.00, 0.10, 0.25, 0.45, 0.60, 0.75, 1.00 };
 Double_t red[7]   = { 1.00, 0.00, 0.00, 0.00, 0.97, 0.97, 0.10 };
 Double_t green[7] = { 1.00, 0.97, 0.30, 0.40, 0.97, 0.00, 0.00 };
 Double_t blue[7]  = { 1.00, 0.97, 0.97, 0.00, 0.00, 0.00, 0.00 };
 TColor::CreateGradientColorTable(NRGBs, stops, red, green, blue, NCont);

 // Make MyStyle_work a copy of MyStyle and remove stats
 // MyStyle_work->SetPadTopMargin(0.1);
 // MyStyle_work->SetPadRightMargin(0.1);


 // Select Which style to use 
 // gROOT->SetStyle("MyStyle");

 // Use the RooFit functions
 // using namespace RooFit;

 // Force Root to run MyStyle/MyStyle_Work style


update: I tried to add My_Style->SetMarkerSize(0); in the rootlogon.C and it seems to be drawing faster.

_ROOT Version:6.26.00 (conda-forge)
_Platform:ubuntu 20.04 (wsl)

Try with “E”. “P” is useless if you do not change the marker style. The default is a dot and you will not see it if you draw also the errors bar (option “E”).

still taking long time …

You said that without rootlogon.C it is fast. Can you identify which line in rootlogon.C makes it slow ? looking at it I do not see anything obvious. Except may be the line width. X11 (the graphics backend used on Ubuntu) is known to be slow when drawing lines with a line width > 1.

setting line width at 1 did not make it faster … get the TStyle and setmarkersize doesnt work. so far i have no idea on where the issue is comming from. So my temporary workaround is to histo.SetMarkerSize(0) before drawing

If you provide me your hitogram and your rootlogon.C I can have a look



outputfile.root (2.0 MB)

I see a small slow down with rootlogon.C. Using:


makes it faster. Whihc is normal because circle markers takes longer tro draw than dot.

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