{
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  {
   "cell_type": "markdown",
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   "source": [
    "# Ratioplot\n",
    "Display two histograms and their ratio.\n",
    "\n",
    "This program illustrates how to plot two histograms and their\n",
    "ratio on the same canvas. Original macro by Olivier Couet.\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "**Author:** Michael Moran  \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 Sunday, January 23, 2022 at 09:32 AM.</small></i>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "from ROOT import TCanvas, TColor, TGaxis, TH1F, TPad\n",
    "from ROOT import kBlack, kBlue, kRed\n",
    "\n",
    "\n",
    "def createH1():\n",
    "    h1 = TH1F(\"h1\", (\"Two gaussian plots and their ratio; x title; h1 and h2\"\n",
    "                \" histograms\"), 100, -5, 5)\n",
    "    h1.SetLineColor(kBlue+1)\n",
    "    h1.SetLineWidth(2)\n",
    "    h1.FillRandom(\"gaus\")\n",
    "    h1.GetYaxis().SetTitleSize(20)\n",
    "    h1.GetYaxis().SetTitleFont(43)\n",
    "    h1.GetYaxis().SetTitleOffset(1.55)\n",
    "    h1.SetStats(0)\n",
    "    return h1\n",
    "\n",
    "\n",
    "def createH2():\n",
    "    h2 = TH1F(\"h2\", \"h2\", 100, -5, 5)\n",
    "    h2.FillRandom(\"gaus\")\n",
    "    h2.SetLineColor(kRed)\n",
    "    h2.SetLineWidth(2)\n",
    "    return h2\n",
    "\n",
    "\n",
    "def createRatio(h1, h2):\n",
    "    h3 = h1.Clone(\"h3\")\n",
    "    h3.SetLineColor(kBlack)\n",
    "    h3.SetMarkerStyle(21)\n",
    "    h3.SetTitle(\"\")\n",
    "    h3.SetMinimum(0.8)\n",
    "    h3.SetMaximum(1.35)\n",
    "    # Set up plot for markers and errors\n",
    "    h3.Sumw2()\n",
    "    h3.SetStats(0)\n",
    "    h3.Divide(h2)\n",
    "\n",
    "    # Adjust y-axis settings\n",
    "    y = h3.GetYaxis()\n",
    "    y.SetTitle(\"ratio h1/h2 \")\n",
    "    y.SetNdivisions(505)\n",
    "    y.SetTitleSize(20)\n",
    "    y.SetTitleFont(43)\n",
    "    y.SetTitleOffset(1.55)\n",
    "    y.SetLabelFont(43)\n",
    "    y.SetLabelSize(15)\n",
    "\n",
    "    # Adjust x-axis settings\n",
    "    x = h3.GetXaxis()\n",
    "    x.SetTitleSize(20)\n",
    "    x.SetTitleFont(43)\n",
    "    x.SetTitleOffset(4.0)\n",
    "    x.SetLabelFont(43)\n",
    "    x.SetLabelSize(15)\n",
    "\n",
    "    return h3\n",
    "\n",
    "\n",
    "def createCanvasPads():\n",
    "    c = TCanvas(\"c\", \"canvas\", 800, 800)\n",
    "    # Upper histogram plot is pad1\n",
    "    pad1 = TPad(\"pad1\", \"pad1\", 0, 0.3, 1, 1.0)\n",
    "    pad1.SetBottomMargin(0)  # joins upper and lower plot\n",
    "    pad1.SetGridx()\n",
    "    pad1.Draw()\n",
    "    # Lower ratio plot is pad2\n",
    "    c.cd()  # returns to main canvas before defining pad2\n",
    "    pad2 = TPad(\"pad2\", \"pad2\", 0, 0.05, 1, 0.3)\n",
    "    pad2.SetTopMargin(0)  # joins upper and lower plot\n",
    "    pad2.SetBottomMargin(0.2)\n",
    "    pad2.SetGridx()\n",
    "    pad2.Draw()\n",
    "\n",
    "    return c, pad1, pad2"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "create required parts"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "h1 = createH1()\n",
    "h2 = createH2()\n",
    "h3 = createRatio(h1, h2)\n",
    "c, pad1, pad2 = createCanvasPads()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "draw everything"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "pad1.cd()\n",
    "h1.Draw()\n",
    "h2.Draw(\"same\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "to avoid clipping the bottom zero, redraw a small axis"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "h1.GetYaxis().SetLabelSize(0.0)\n",
    "axis = TGaxis(-5, 20, -5, 220, 20, 220, 510, \"\")\n",
    "axis.SetLabelFont(43)\n",
    "axis.SetLabelSize(15)\n",
    "axis.Draw()\n",
    "pad2.cd()\n",
    "h3.Draw(\"ep\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "To hold window open when running from command line\n",
    " text = raw_input()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Draw all canvases "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "from ROOT import gROOT \n",
    "gROOT.GetListOfCanvases().Draw()"
   ]
  }
 ],
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