{
 "cells": [
  {
   "cell_type": "markdown",
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   "source": [
    "# hist009_TH1_normalize\n",
    "\n",
    "Image produced by `.x NormalizeHistogram.C`\n",
    "Two different methods of normalizing histograms\n",
    "are shown, each with the original histogram.\n",
    "next to the normalized one.\n",
    "\n",
    "\n",
    "\n",
    "**Author:** Advait Dhingra  \n",
    "<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 Tuesday, May 19, 2026 at 08:12 PM.</small></i>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "46a89cc0",
   "metadata": {
    "collapsed": false,
    "execution": {
     "iopub.execute_input": "2026-05-19T20:12:04.280775Z",
     "iopub.status.busy": "2026-05-19T20:12:04.280653Z",
     "iopub.status.idle": "2026-05-19T20:12:04.594754Z",
     "shell.execute_reply": "2026-05-19T20:12:04.594220Z"
    }
   },
   "outputs": [],
   "source": [
    "const std::array<double, 6> binsx{0, 5, 10, 20, 50, 100};\n",
    "TH1D *orig = new TH1D(\"orig\", \"Original histogram before normalization\", binsx.size() - 1, binsx.data());\n",
    "\n",
    "gStyle->SetTitleFontSize(0.06);"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "466e00b7",
   "metadata": {},
   "source": [
    "Filling histogram with random entries"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "7aef3143",
   "metadata": {
    "collapsed": false,
    "execution": {
     "iopub.execute_input": "2026-05-19T20:12:04.596754Z",
     "iopub.status.busy": "2026-05-19T20:12:04.596611Z",
     "iopub.status.idle": "2026-05-19T20:12:04.799949Z",
     "shell.execute_reply": "2026-05-19T20:12:04.799637Z"
    }
   },
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "input_line_53:8:1: warning: 'norm' shadows a declaration with the same name in the 'std' namespace; use '::norm' to reference this declaration\n",
      "TH1D *norm = static_cast<TH1D *>(orig->Clone(\"norm\"));\n",
      "^\n"
     ]
    }
   ],
   "source": [
    "TRandom2 rand;\n",
    "for (int i = 0; i < 100000; ++i) {\n",
    "   double r = rand.Rndm() * 100;\n",
    "   orig->Fill(r);\n",
    "}\n",
    "\n",
    "TH1D *norm = static_cast<TH1D *>(orig->Clone(\"norm\"));\n",
    "norm->SetTitle(\"Normalized Histogram\");"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "c01eb846",
   "metadata": {},
   "source": [
    "Normalizing the Histogram by scaling by 1 / the integral and taking width into account"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "843adce9",
   "metadata": {
    "collapsed": false,
    "execution": {
     "iopub.execute_input": "2026-05-19T20:12:04.807353Z",
     "iopub.status.busy": "2026-05-19T20:12:04.807181Z",
     "iopub.status.idle": "2026-05-19T20:12:05.029826Z",
     "shell.execute_reply": "2026-05-19T20:12:05.017577Z"
    }
   },
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "input_line_55:2:2: error: reference to 'norm' is ambiguous\n",
      " norm->Scale(1. / norm->Integral(), \"width\");\n",
      " ^\n",
      "input_line_53:8:7: note: candidate found by name lookup is 'norm'\n",
      "TH1D *norm = static_cast<TH1D *>(orig->Clone(\"norm\"));\n",
      "      ^\n",
      "/usr/lib/gcc/x86_64-redhat-linux/14/../../../../include/c++/14/complex:2453:5: note: candidate found by name lookup is 'std::norm'\n",
      "    norm(_Tp __x)\n",
      "    ^\n",
      "/usr/lib/gcc/x86_64-redhat-linux/14/../../../../include/c++/14/complex:959:5: note: candidate found by name lookup is 'std::norm'\n",
      "    norm(const complex<_Tp>& __z)\n",
      "    ^\n"
     ]
    }
   ],
   "source": [
    "norm->Scale(1. / norm->Integral(), \"width\");"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "30a4c5c5",
   "metadata": {},
   "source": [
    "Drawing everything"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "4a91fab0",
   "metadata": {
    "collapsed": false,
    "execution": {
     "iopub.execute_input": "2026-05-19T20:12:05.033422Z",
     "iopub.status.busy": "2026-05-19T20:12:05.033235Z",
     "iopub.status.idle": "2026-05-19T20:12:05.238531Z",
     "shell.execute_reply": "2026-05-19T20:12:05.237867Z"
    }
   },
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "input_line_56:8:1: error: reference to 'norm' is ambiguous\n",
      "norm->Draw();\n",
      "^\n",
      "input_line_53:8:7: note: candidate found by name lookup is 'norm'\n",
      "TH1D *norm = static_cast<TH1D *>(orig->Clone(\"norm\"));\n",
      "      ^\n",
      "/usr/lib/gcc/x86_64-redhat-linux/14/../../../../include/c++/14/complex:2453:5: note: candidate found by name lookup is 'std::norm'\n",
      "    norm(_Tp __x)\n",
      "    ^\n",
      "/usr/lib/gcc/x86_64-redhat-linux/14/../../../../include/c++/14/complex:959:5: note: candidate found by name lookup is 'std::norm'\n",
      "    norm(const complex<_Tp>& __z)\n",
      "    ^\n"
     ]
    }
   ],
   "source": [
    "TCanvas *c1 = new TCanvas(\"c1\", \"Histogram Normalization\", 700, 900);\n",
    "c1->Divide(1, 2);\n",
    "\n",
    "c1->cd(1);\n",
    "orig->Draw();\n",
    "c1->cd(2);\n",
    "norm->Draw();"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "48a2fa03",
   "metadata": {},
   "source": [
    "Draw all canvases "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "2bd29372",
   "metadata": {
    "collapsed": false,
    "execution": {
     "iopub.execute_input": "2026-05-19T20:12:05.240433Z",
     "iopub.status.busy": "2026-05-19T20:12:05.240267Z",
     "iopub.status.idle": "2026-05-19T20:12:05.503646Z",
     "shell.execute_reply": "2026-05-19T20:12:05.481767Z"
    }
   },
   "outputs": [],
   "source": [
    "%jsroot on\n",
    "gROOT->GetListOfCanvases()->Draw()"
   ]
  }
 ],
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