{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "74669f32",
   "metadata": {},
   "source": [
    "# gr010_approx_smooth\n",
    "\n",
    "See the [TGraphSmooth documentation](https://root.cern/doc/master/classTGraphSmooth.html)\n",
    "\n",
    "\n",
    "\n",
    "**Author:** Christian Stratowa, Vienna, Austria.  \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 08:37 PM.</small></i>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "f5d293ea",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "TCanvas *vC1;\n",
    "TGraph *grxy, *grin, *grout;"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "cacb6b06",
   "metadata": {},
   "source": [
    " Definition of a helper function: "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "1da27dc4",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "%%cpp -d\n",
    "void DrawSmooth(Int_t pad, const char *title, const char *xt, const char *yt)\n",
    "{\n",
    "  vC1->cd(pad);\n",
    "  TH1F *vFrame = gPad->DrawFrame(0,0,15,150);\n",
    "  vFrame->SetTitle(title);\n",
    "  vFrame->SetTitleSize(0.2);\n",
    "  vFrame->SetXTitle(xt);\n",
    "  vFrame->SetYTitle(yt);\n",
    "  grxy->SetMarkerColor(kBlue);\n",
    "  grxy->SetMarkerStyle(21);\n",
    "  grxy->SetMarkerSize(0.5);\n",
    "  grxy->Draw(\"P\");\n",
    "  grin->SetMarkerColor(kRed);\n",
    "  grin->SetMarkerStyle(5);\n",
    "  grin->SetMarkerSize(0.7);\n",
    "  grin->Draw(\"P\");\n",
    "  grout->DrawClone(\"LP\");\n",
    "}"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "faf563b4",
   "metadata": {},
   "source": [
    "Test data (square)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "c8a73fe8",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "Int_t n = 11;\n",
    "Double_t x[] = {1,2,3,4,5,6,6,6,8,9,10};\n",
    "Double_t y[] = {1,4,9,16,25,25,36,49,64,81,100};\n",
    "grxy = new TGraph(n,x,y);"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "4c2842a5",
   "metadata": {},
   "source": [
    "X values, for which y values should be interpolated"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "5cd18177",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "Int_t nout = 14;\n",
    "Double_t xout[] =\n",
    "   {1.2,1.7,2.5,3.2,4.4,5.2,5.7,6.5,7.6,8.3,9.7,10.4,11.3,13};"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "9d3e0a07",
   "metadata": {},
   "source": [
    "Create Canvas"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "c109d66a",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "vC1 = new TCanvas(\"vC1\",\"square\",200,10,700,700);\n",
    "vC1->Divide(2,2);"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "6335ae56",
   "metadata": {},
   "source": [
    "Initialize graph with data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "afb90eb3",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "grin = new TGraph(n,x,y);"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "09aff921",
   "metadata": {},
   "source": [
    "Interpolate at equidistant points (use mean for tied x-values)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "d4094726",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "TGraphSmooth *gs = new TGraphSmooth(\"normal\");\n",
    "grout = gs->Approx(grin,\"linear\");\n",
    "DrawSmooth(1,\"Approx: ties = mean\",\"X-axis\",\"Y-axis\");"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "95cd6d0c",
   "metadata": {},
   "source": [
    "Re-initialize graph with data\n",
    "(since graph points were set to unique vales)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "5532cadd",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "grin = new TGraph(n,x,y);"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "abeb3eb2",
   "metadata": {},
   "source": [
    "Interpolate at given points xout"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "61e75645",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "grout = gs->Approx(grin,\"linear\", 14, xout, 0, 130);\n",
    "DrawSmooth(2,\"Approx: ties = mean\",\"\",\"\");"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "ace7eb8a",
   "metadata": {},
   "source": [
    "Print output variables for given values xout"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "cf58bd41",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "Int_t vNout = grout->GetN();\n",
    "Double_t vXout, vYout;\n",
    "for (Int_t k=0;k<vNout;k++) {\n",
    "   grout->GetPoint(k, vXout, vYout);\n",
    "   cout << \"k= \" << k << \"  vXout[k]= \" << vXout\n",
    "        << \"  vYout[k]= \" << vYout << endl;\n",
    "}"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "0a6c8748",
   "metadata": {},
   "source": [
    "Re-initialize graph with data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "818a7fd0",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "grin = new TGraph(n,x,y);"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "0967bf5a",
   "metadata": {},
   "source": [
    "Interpolate at equidistant points (use min for tied x-values)\n",
    "_grout = gs->Approx(grin,\"linear\", 50, 0, 0, 0, 1, 0, \"min\");_"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "c4b0e799",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "grout = gs->Approx(grin,\"constant\", 50, 0, 0, 0, 1, 0.5, \"min\");\n",
    "DrawSmooth(3,\"Approx: ties = min\",\"\",\"\");"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "982caefa",
   "metadata": {},
   "source": [
    "Re-initialize graph with data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "faab82bf",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "grin = new TGraph(n,x,y);"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "41e11410",
   "metadata": {},
   "source": [
    "Interpolate at equidistant points (use max for tied x-values)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "cfcd667a",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "grout = gs->Approx(grin,\"linear\", 14, xout, 0, 0, 2, 0, \"max\");\n",
    "DrawSmooth(4,\"Approx: ties = max\",\"\",\"\");"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "e0984497",
   "metadata": {},
   "source": [
    "Cleanup"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "5fe84169",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "delete gs;"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "10331e6f",
   "metadata": {},
   "source": [
    "Draw all canvases "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "fa3a0d84",
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "%jsroot on\n",
    "gROOT->GetListOfCanvases()->Draw()"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "ROOT C++",
   "language": "c++",
   "name": "root"
  },
  "language_info": {
   "codemirror_mode": "text/x-c++src",
   "file_extension": ".C",
   "mimetype": " text/x-c++src",
   "name": "c++"
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 },
 "nbformat": 4,
 "nbformat_minor": 5
}