#!/usr/bin/env python
# coding: utf-8

# # rf105_funcbinding
# 'BASIC FUNCTIONALITY' RooFit tutorial macro #105
# Demonstration of binding ROOT Math functions as RooFit functions
# and pdfs
# 
# 
# 
# 
# **Author:**  Clemens Lange, Wouter Verkerke (C version)  
# <i><small>This notebook tutorial was automatically generated with <a href= "https://github.com/root-project/root/blob/master/documentation/doxygen/converttonotebook.py">ROOTBOOK-izer</a> from the macro found in the ROOT repository  on Wednesday, April 17, 2024 at 11:16 AM.</small></i>

# In[1]:


import ROOT


# Bind ROOT TMath::Erf C function
# ---------------------------------------------------

# Bind one-dimensional ROOT.TMath.Erf function as ROOT.RooAbsReal function

# In[2]:


x = ROOT.RooRealVar("x", "x", -3, 3)
erf = ROOT.RooFit.bindFunction("erf", ROOT.TMath.Erf, x)


# Print erf definition

# In[3]:


erf.Print()


# Plot erf on frame

# In[4]:


frame1 = x.frame(Title="TMath.Erf bound as ROOT.RooFit function")
erf.plotOn(frame1)


# Bind ROOT::Math::beta_pdf C function
# -----------------------------------------------------------------------

# Bind pdf ROOT.Math.Beta with three variables as ROOT.RooAbsPdf function

# In[5]:


x2 = ROOT.RooRealVar("x2", "x2", 0, 0.999)
a = ROOT.RooRealVar("a", "a", 5, 0, 10)
b = ROOT.RooRealVar("b", "b", 2, 0, 10)
beta = ROOT.RooFit.bindPdf("beta", ROOT.Math.beta_pdf, x2, a, b)


# Perf beta definition

# In[6]:


beta.Print()


# Generate some events and fit

# In[7]:


data = beta.generate({x2}, 10000)
beta.fitTo(data, PrintLevel=-1)


# Plot data and pdf on frame

# In[8]:


frame2 = x2.frame(Title="ROOT.Math.Beta bound as ROOT.RooFit pdf")
data.plotOn(frame2)
beta.plotOn(frame2)


# Bind ROOT TF1 as RooFit function
# ---------------------------------------------------------------

# Create a ROOT TF1 function

# In[9]:


fa1 = ROOT.TF1("fa1", "sin(x)/x", 0, 10)


# Create an observable

# In[10]:


x3 = ROOT.RooRealVar("x3", "x3", 0.01, 20)


# Create binding of TF1 object to above observable

# In[11]:


rfa1 = ROOT.RooFit.bindFunction(fa1, x3)


# Print rfa1 definition

# In[12]:


rfa1.Print()


# Make plot frame in observable, TF1 binding function

# In[13]:


frame3 = x3.frame(Title="TF1 bound as ROOT.RooFit function")
rfa1.plotOn(frame3)

c = ROOT.TCanvas("rf105_funcbinding", "rf105_funcbinding", 1200, 400)
c.Divide(3)
c.cd(1)
ROOT.gPad.SetLeftMargin(0.15)
frame1.GetYaxis().SetTitleOffset(1.6)
frame1.Draw()
c.cd(2)
ROOT.gPad.SetLeftMargin(0.15)
frame2.GetYaxis().SetTitleOffset(1.6)
frame2.Draw()
c.cd(3)
ROOT.gPad.SetLeftMargin(0.15)
frame3.GetYaxis().SetTitleOffset(1.6)
frame3.Draw()

c.SaveAs("rf105_funcbinding.png")


# Draw all canvases 

# In[14]:


from ROOT import gROOT 
gROOT.GetListOfCanvases().Draw()