rf503_wspaceread.py

# /
#
# 'ORGANIZATION AND SIMULTANEOUS FITS' ROOT.RooFit tutorial macro #503
#
# Reading and using a workspace
#
# -. ROOT.The input file for self macro is generated by rf502_wspaceread.C
#
#
# 07/2008 - Wouter Verkerke
#
# /


import ROOT


def rf503_wspaceread():
    # R e a d   w o r k s p a c e   f r o m   f i l e
    # -----------------------------------------------

    # Open input file with workspace (generated by rf14_wspacewrite)
    f = ROOT.TFile("rf502_workspace.root")

    # Retrieve workspace from file
    w = f.Get("w")

    # R e t r i e v e   p d f , a t a   f r o m   w o r k s p a c e
    # -----------------------------------------------------------------

    # Retrieve x, and data from workspace
    x = w.var("x")
    model = w.pdf("model")
    data = w.data("modelData")

    # Print structure of composite p.d.f.
    model.Print("t")

    # F i t   m o d e l   t o   d a t a , l o t   m o d e l
    # ---------------------------------------------------------

    # Fit model to data
    model.fitTo(data)

    # Plot data and PDF overlaid
    xframe = x.frame(ROOT.RooFit.Title("Model and data read from workspace"))
    data.plotOn(xframe)
    model.plotOn(xframe)

    # Overlay the background component of model with a dashed line
    model.plotOn(xframe, ROOT.RooFit.Components("bkg"),
                 ROOT.RooFit.LineStyle(ROOT.kDashed))

    # Overlay the background+sig2 components of model with a dotted line
    model.plotOn(xframe, ROOT.RooFit.Components("bkg,sig2"),
                 ROOT.RooFit.LineStyle(ROOT.kDotted))

    # Draw the frame on the canvas
    c = ROOT.TCanvas("rf503_wspaceread", "rf503_wspaceread", 600, 600)
    ROOT.gPad.SetLeftMargin(0.15)
    xframe.GetYaxis().SetTitleOffset(1.4)
    xframe.Draw()

    c.SaveAs("rf503_wspaceread.png")


if __name__ == "__main__":
    rf503_wspaceread()