From 914e46f1c591f8b9b34115863ff31e42e19bfb97 Mon Sep 17 00:00:00 2001
From: Mattias Ellert <mattias.ellert@physics.uu.se>
Date: Mon, 28 Mar 2022 09:32:24 +0200
Subject: [PATCH] Use calls from Python directly

The rf105_funcbinding.py tutorial used to trigger errors due to unknown
symbols. In particular the custum new and delete operators used in RooFit
were not autoloaded when needed.

In the tutorial there was a workaround implemented to call ProcessLine
instead of making calls directly form Python, to make the autoloading
from the C++ side of ROOT instead. This did not quite fix the problem,
and the tutorial still randomly failed due to missing symbols.

After changing the algorthm used for autoloading in commit
6ae602bba7d33c900a117c9de0187ab5a28e14b8 these problems were solved.

After this fix using the direct calls from Python also works, so this
PR suggests updating the tutorial to do that.
---
 tutorials/roofit/rf105_funcbinding.py | 30 ++++++---------------------
 1 file changed, 6 insertions(+), 24 deletions(-)

diff --git a/tutorials/roofit/rf105_funcbinding.py b/tutorials/roofit/rf105_funcbinding.py
index 72d9cf62fc..b9de2a095a 100644
--- a/tutorials/roofit/rf105_funcbinding.py
+++ b/tutorials/roofit/rf105_funcbinding.py
@@ -17,15 +17,8 @@ import ROOT
 # ---------------------------------------------------
 
 # Bind one-dimensional ROOT.TMath.Erf function as ROOT.RooAbsReal function
-# Directly trying this in python doesn't work:
-# x = ROOT.RooRealVar("x", "x", -3, 3)
-# erf = ROOT.RooFit.bindFunction("erf", ROOT.TMath.Erf, x)
-# Need to go through C interface
-ROOT.gInterpreter.ProcessLine(
-    'auto x = RooRealVar("x", "x", -3, 3); auto myerf = RooFit::bindFunction("erf", TMath::Erf, x)'
-)
-x = ROOT.x
-erf = ROOT.myerf
+x = ROOT.RooRealVar("x", "x", -3, 3)
+erf = ROOT.RooFit.bindFunction("erf", ROOT.TMath.Erf, x)
 
 # Print erf definition
 erf.Print()
@@ -38,21 +31,10 @@ erf.plotOn(frame1)
 # -----------------------------------------------------------------------
 
 # Bind pdf ROOT.Math.Beta with three variables as ROOT.RooAbsPdf function
-# As above, this does not work directly in python
-# 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)
-ROOT.gInterpreter.ProcessLine(
-    'auto x2 = RooRealVar("x2", "x2", 0, 0.999);\
-    auto a = RooRealVar("a", "a", 5, 0, 10);\
-    auto b = RooRealVar("b", "b", 5, 0, 10);\
-    auto beta = RooFit::bindPdf("beta", ROOT::Math::beta_pdf, x2, a, b)'
-)
-x2 = ROOT.x2
-a = ROOT.a
-b = ROOT.b
-beta = ROOT.beta
+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
 beta.Print()
-- 
2.35.1