{
"cells": [
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"source": [
"# hist031_TRatioPlot_residual_fit\n",
"Example which shows how you can get the graph of the lower plot and set the y axis range for it.\n",
"\n",
"Since the lower plot is not created until `TRatioPlot::Draw` is called, you can only use the method\n",
"afterwards.\n",
"Inspired by the tutorial of Paul Gessinger.\n",
"\n",
"\n",
"\n",
"\n",
"**Author:** Alberto Ferro \n",
"This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, May 19, 2026 at 08:12 PM."
]
},
{
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"id": "5f79a247",
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"shell.execute_reply": "2026-05-19T20:12:42.914537Z"
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"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"****************************************\n",
"Minimizer is Minuit2 / Migrad\n",
"Chi2 = 22.1778\n",
"NDf = 33\n",
"Edm = 6.53577e-08\n",
"NCalls = 55\n",
"Constant = 158.988 +/- 4.47298 \n",
"Mean = 0.00662197 +/- 0.0225355 \n",
"Sigma = 0.993481 +/- 0.0169678 \t (limited)\n"
]
},
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"text/html": [
"\n",
"\n",
"\n",
"
\n",
"\n",
"\n",
"\n"
],
"text/plain": [
""
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},
"metadata": {},
"output_type": "display_data"
}
],
"source": [
"import ROOT\n",
"\n",
"ROOT.gStyle.SetOptStat(0)\n",
"c1 = ROOT.TCanvas(\"c1\", \"fit residual simple\")\n",
"c1.SetLogy()\n",
"\n",
"h1 = ROOT.TH1D(\"h1\", \"h1\", 50, -5, 5)\n",
"h1.FillRandom(\"gaus\", 2000)\n",
"h1.Fit(\"gaus\")\n",
"h1.SetMinimum(0.001)\n",
"h1.GetXaxis().SetTitle(\"x\")\n",
"h1.GetYaxis().SetTitle(\"y\")\n",
"\n",
"rp1 = ROOT.TRatioPlot(h1)\n",
"rp1.Draw()\n",
"rp1.GetLowerRefGraph().SetMinimum(-2)\n",
"rp1.GetLowerRefGraph().SetMaximum(2)\n",
"\n",
"c1.Update()"
]
},
{
"cell_type": "markdown",
"id": "20dfe083",
"metadata": {},
"source": [
"Draw all canvases "
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "c54b7f70",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:12:42.923859Z",
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"outputs": [
{
"data": {
"text/html": [
"\n",
"\n",
"\n",
"
\n",
"\n",
"\n",
"\n"
],
"text/plain": [
""
]
},
"metadata": {},
"output_type": "display_data"
}
],
"source": [
"from ROOT import gROOT \n",
"gROOT.GetListOfCanvases().Draw()"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
"name": "python3"
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