[hist] Add tutorial for profile histograms

hist/histv7/inc/ROOT/RProfile.hxx

@@ -123,6 +123,21 @@ public:
          Internal::AtomicAdd(&fSum, rhs.fSum);
          Internal::AtomicAdd(&fSum2, rhs.fSum2);
       }
+
+      /// Compute the arithmetic mean in this bin.
+      ///
+      /// \f[
+      /// \mu = \frac{\sum w_i \cdot x_i}{\sum w_i}
+      /// \f]
+      ///
+      /// \return the arithmetic mean in this bin
+      double ComputeMean() const
+      {
+         if (fSum == 0) {
+            return std::numeric_limits<double>::signaling_NaN();
+         }
+         return fSumValues / fSum;
+      }
    };
 
 private:

hist/histv7/test/hist_profile.cxx

@@ -235,6 +235,22 @@ TEST(RProfile, Clone)
    EXPECT_EQ(profileB.GetBinContent(9).fSumValues, 25.0);
 }
 
+TEST(RProfile, ComputeMean)
+{
+   static constexpr std::size_t Bins = 20;
+   RProfile profile(Bins, {0, Bins});
+   EXPECT_TRUE(std::isnan(profile.GetBinContent(0).ComputeMean()));
+
+   profile.Fill(8.5, 23.0);
+   profile.Fill(8.5, 25.0);
+
+   profile.Fill(9.5, 23.0, RWeight(0.8));
+   profile.Fill(9.5, 25.0, RWeight(0.7));
+
+   EXPECT_EQ(profile.GetBinContent(8).ComputeMean(), 24.0);
+   EXPECT_FLOAT_EQ(profile.GetBinContent(9).ComputeMean(), 23.933333);
+}
+
 TEST(RProfile, Fill)
 {
    static constexpr std::size_t Bins = 20;

tutorials/hist/histv7/hist010_RProfile.C

@@ -0,0 +1,90 @@
+/// \file
+/// \ingroup tutorial_histv7
+///
+/// Profile histograms with RProfile.
+///
+/// \macro_code
+/// \macro_output
+///
+/// \date July 2026
+/// \author The ROOT Team
+
+#include <ROOT/RBinIndex.hxx>
+#include <ROOT/RProfile.hxx>
+#include <ROOT/RRegularAxis.hxx>
+
+#include <cstddef>
+#include <iostream>
+#include <random>
+
+void hist010_RProfile()
+{
+   // Create an axis that can be used for multiple histograms.
+   ROOT::Experimental::RRegularAxis axis(40, {0.0, 20.0});
+
+   // Create a profile histogram and fill with random values.
+   ROOT::Experimental::RProfile profile(40, {0.0, 20.0});
+
+   std::mt19937 gen;
+   // Create a first normal distribution with mean 10.0 and stddev 4.0.
+   std::normal_distribution normal1(10.0, 4.0);
+   // Create a second normal distribution for the value.
+   std::normal_distribution normal2(40.0, 10.0);
+   for (std::size_t i = 0; i < 1000; i++) {
+      double x = normal1(gen);
+      double v = normal2(gen);
+      profile.Fill(x, v);
+   }
+
+   // Print (some of) the global statistics.
+   std::cout << "entries = " << profile.GetNEntries() << "\n";
+   std::cout << "binned mean = " << profile.ComputeMean(0);
+   std::cout << ", stddev = " << profile.ComputeStdDev(0);
+   std::cout << "\n";
+
+   // "Draw" the entries of the profile histogram with ASCII characters. The height is hard-coded to work for this
+   // tutorial.
+   for (int row = 8; row > 0; row--) {
+      auto print = [&](ROOT::Experimental::RBinIndex bin) {
+         const auto &content = profile.GetBinContent(bin);
+         static constexpr int Scale = 10;
+         std::cout << (content.fSum >= (row * Scale) ? '*' : ' ');
+      };
+
+      // First the underflow bin, separated by a vertical bar.
+      print(ROOT::Experimental::RBinIndex::Underflow());
+      std::cout << '|';
+
+      // Now iterate the normal bins and print a '*' if the value is sufficiently large.
+      for (auto bin : axis.GetNormalRange()) {
+         print(bin);
+      }
+
+      // Finally the overflow bin after a separating vertical bar.
+      std::cout << '|';
+      print(ROOT::Experimental::RBinIndex::Overflow());
+      std::cout << "\n";
+   }
+
+   std::cout << "\n";
+   std::cout << "value mean = " << profile.ComputeMean(1);
+   std::cout << ", stddev = " << profile.ComputeStdDev(1);
+   std::cout << "\n";
+
+   auto printBin = [&](ROOT::Experimental::RBinIndex bin) {
+      const auto &content = profile.GetBinContent(bin);
+      std::cout << "entries = " << content.fSum << ", mean = " << content.ComputeMean();
+   };
+
+   std::cout << "underflow bin: ";
+   printBin(ROOT::Experimental::RBinIndex::Underflow());
+   std::cout << "\n";
+
+   std::cout << "bin #5: ";
+   printBin(5);
+   std::cout << "\n";
+
+   std::cout << "bin #10: ";
+   printBin(10);
+   std::cout << "\n";
+}

tutorials/hist/histv7/index.md

@@ -1,4 +1,4 @@
-\defgroup tutorial_histv7 RHist tutorials
+\defgroup tutorial_histv7 Experimental histogram tutorials
 \ingroup tutorial_hist
 
 Examples demonstrating ROOT's histogram package.
@@ -10,6 +10,7 @@ Examples demonstrating ROOT's histogram package.
 | hist003_RHist_multi.C | Multidimensional RHist with different axis types. |
 | hist004_RHist_concurrent.C | Concurrent filling of RHist. |
 | hist005_RHist_convert_TH1.C | Conversion of RHist to TH1. |
+| hist010_RProfile.C | Profile histograms with RProfile. |
 
 A second set of tutorials demonstrates usage with RDataFrame.