[RF] Don't override integral normalization set in RooNormalizedPdf

We should not override the normalization set for integrals of a
RooNormalizedPdf, because sometimes, the requested normalization set is
explicitly different from the internal normalization set of the
normalized pdf.

Closes #18718.

(cherry picked from commit 075d432)

Author: guitargeek

roofit/roofitcore/inc/RooFit/Detail/RooNormalizedPdf.h

@@ -16,8 +16,7 @@
 #include <RooAbsPdf.h>
 #include <RooRealProxy.h>
 
-namespace RooFit {
-namespace Detail {
+namespace RooFit::Detail {
 
 class RooNormalizedPdf : public RooAbsPdf {
 public:
@@ -51,16 +50,15 @@ class RooNormalizedPdf : public RooAbsPdf {
 
    bool forceAnalyticalInt(const RooAbsArg & /*dep*/) const override { return true; }
    /// Forward determination of analytical integration capabilities to input p.d.f
-   Int_t getAnalyticalIntegralWN(RooArgSet &allVars, RooArgSet &analVars, const RooArgSet * /*normSet*/,
+   Int_t getAnalyticalIntegralWN(RooArgSet &allVars, RooArgSet &analVars, const RooArgSet *normSet,
                                  const char *rangeName = nullptr) const override
    {
-      return _pdf->getAnalyticalIntegralWN(allVars, analVars, &_normSet, rangeName);
+      return _pdf->getAnalyticalIntegralWN(allVars, analVars, normSet ? normSet : &_normSet, rangeName);
    }
    /// Forward calculation of analytical integrals to input p.d.f
-   double
-   analyticalIntegralWN(Int_t code, const RooArgSet * /*normSet*/, const char *rangeName = nullptr) const override
+   double analyticalIntegralWN(Int_t code, const RooArgSet *normSet, const char *rangeName = nullptr) const override
    {
-      return _pdf->analyticalIntegralWN(code, &_normSet, rangeName);
+      return _pdf->analyticalIntegralWN(code, normSet ? normSet : &_normSet, rangeName);
    }
 
    ExtendMode extendMode() const override { return static_cast<RooAbsPdf &>(*_pdf).extendMode(); }
@@ -97,7 +95,6 @@ class RooNormalizedPdf : public RooAbsPdf {
    ClassDefOverride(RooFit::Detail::RooNormalizedPdf, 0);
 };
 
-} // namespace Detail
-} // namespace RooFit
+} // namespace RooFit::Detail
 
 #endif

roofit/roofitcore/src/RooNormalizedPdf.cxx

@@ -16,16 +16,14 @@
 
 #include <array>
 
-
 /**
  * \class RooNormalizedPdf
  *
  * A RooNormalizedPdf wraps a pdf divided by its integral for a given
  * normalization set into a new self-normalized pdf.
  */
 
-namespace RooFit {
-namespace Detail {
+namespace RooFit::Detail {
 
 void RooNormalizedPdf::doEval(RooFit::EvalContext &ctx) const
 {
@@ -53,5 +51,4 @@ void RooNormalizedPdf::doEval(RooFit::EvalContext &ctx) const
    }
 }
 
-} // namespace Detail
-} // namespace RooFit
+} // namespace RooFit::Detail

roofit/roofitcore/test/testRooSimultaneous.cxx

@@ -2,10 +2,12 @@
 // Authors: Jonas Rembser, CERN  06/2021
 
 #include <Roo1DTable.h>
+#include <RooAddPdf.h>
 #include <RooAddition.h>
 #include <RooCategory.h>
 #include <RooConstVar.h>
 #include <RooDataSet.h>
+#include <RooExponential.h>
 #include <RooFitResult.h>
 #include <RooGenericPdf.h>
 #include <RooHelpers.h>
@@ -511,6 +513,51 @@ TEST_P(TestStatisticTest, RooSimultaneousSingleChannelCrossCheckWithCondVar)
       << "Inconsistency in RooSimultaneous wrapping with ConditionalObservables";
 }
 
+/// GitHub issue #18718.
+/// Make sure that we can do a ranged fit on an extended RooAddPdf in a
+/// RooSimultaneous with the new CPU backend.
+TEST(RooSimultaneous, RangedExtendedRooAddPdf)
+{
+
+   const double nBkgA_nom = 9000;
+   const double nBkgB_nom = 10000;
+
+   RooRealVar x("x", "Observable", 100, 150);
+   x.setRange("fitRange", 100, 130);
+
+   RooRealVar nBkgA("nBkgA", "", nBkgA_nom, 0.8 * nBkgA_nom, 1.2 * nBkgA_nom);
+   RooRealVar nBkgB("nBkgB", "", nBkgB_nom, 0.8 * nBkgB_nom, 1.2 * nBkgB_nom);
+
+   RooExponential expA("expA", "", x, RooFit::RooConst(-0.06));
+   RooAddPdf modelA("modelA", "", {expA}, {nBkgA});
+
+   RooExponential expB("expB", "", x, RooFit::RooConst(-0.09));
+   RooAddPdf modelB("modelB", "", {expB}, {nBkgB});
+
+   RooCategory runCat("runCat", "", {{"RunA", 0}, {"RunB", 1}});
+
+   RooSimultaneous simPdf("simPdf", "", {{"RunA", &modelA}, {"RunB", &modelB}}, runCat);
+
+   using namespace RooFit;
+
+   std::unique_ptr<RooDataSet> combData{simPdf.generate(RooArgSet(x, runCat), Extended())};
+
+   using Res = std::unique_ptr<RooFitResult>;
+
+   RooArgSet params;
+   RooArgSet paramsSnap;
+   simPdf.getParameters(combData->get(), params);
+   params.snapshot(paramsSnap);
+
+   Res fitResult{simPdf.fitTo(*combData, Save(), Range("fitRange"), EvalBackend(RooFit::EvalBackend::Cpu()))};
+
+   params.assign(paramsSnap);
+
+   Res fitResultRef{simPdf.fitTo(*combData, Save(), Range("fitRange"), EvalBackend(RooFit::EvalBackend::Legacy()))};
+
+   EXPECT_TRUE(fitResult->isIdentical(*fitResultRef));
+}
+
 /// GitHub issue #20383.
 /// Check that the the simultaneous pdf is normalized correctly when plotting
 /// with a projection dataset.