{
"cells": [
{
"cell_type": "markdown",
"id": "9a0e812b",
"metadata": {},
"source": [
"# gr007_multigraph\n",
"Allowing to overlay different graphs can be useful for comparing different datasets\n",
"or for plotting multiple related graphs on the same canvas.\n",
"\n",
"\n",
"\n",
"\n",
"**Author:** Rene Brun \n",
"This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, May 19, 2026 at 08:37 PM."
]
},
{
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"execution_count": 1,
"id": "c582da81",
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"shell.execute_reply": "2026-05-19T20:37:51.742671Z"
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"outputs": [],
"source": [
"gStyle->SetOptFit();\n",
"auto c1 = new TCanvas(\"c1\",\"multigraph\",700,500);\n",
"c1->SetGrid();"
]
},
{
"cell_type": "markdown",
"id": "418f73db",
"metadata": {},
"source": [
"Initialize a TMultiGraph to hold multiple graphs\n",
"This ensures the entire dataset from all added graphs is visible without manual range adjustments."
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "2b4e9d3b",
"metadata": {
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"shell.execute_reply": "2026-05-19T20:37:51.980392Z"
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},
"outputs": [],
"source": [
"auto mg = new TMultiGraph();"
]
},
{
"cell_type": "markdown",
"id": "a3240f17",
"metadata": {},
"source": [
"Create first graph"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "fd55c904",
"metadata": {
"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:37:52.347400Z"
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"source": [
"const Int_t n1 = 10;\n",
"Double_t px1[] = {-0.1, 0.05, 0.25, 0.35, 0.5, 0.61,0.7,0.85,0.89,0.95};\n",
"Double_t py1[] = {-1,2.9,5.6,7.4,9,9.6,8.7,6.3,4.5,1};\n",
"Double_t ex1[] = {.05,.1,.07,.07,.04,.05,.06,.07,.08,.05};\n",
"Double_t ey1[] = {.8,.7,.6,.5,.4,.4,.5,.6,.7,.8};\n",
"auto gr1 = new TGraphErrors(n1,px1,py1,ex1,ey1);\n",
"gr1->SetMarkerColor(kBlue);\n",
"gr1->SetMarkerStyle(21);\n",
"\n",
"gr1->Fit(\"gaus\",\"q\");\n",
"auto func1 = (TF1 *) gr1->GetListOfFunctions()->FindObject(\"gaus\");\n",
"func1->SetLineColor(kBlue);"
]
},
{
"cell_type": "markdown",
"id": "d96c3b91",
"metadata": {},
"source": [
"Add the first graph to the multigraph"
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "05d153d0",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:37:52.365724Z",
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"shell.execute_reply": "2026-05-19T20:37:52.585600Z"
}
},
"outputs": [],
"source": [
"mg->Add(gr1);"
]
},
{
"cell_type": "markdown",
"id": "02e2c282",
"metadata": {},
"source": [
"Create second graph"
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "9c648954",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:37:52.596449Z",
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"shell.execute_reply": "2026-05-19T20:37:52.845653Z"
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"outputs": [],
"source": [
"const Int_t n2 = 10;\n",
"Float_t x2[] = {-0.28, 0.005, 0.19, 0.29, 0.45, 0.56,0.65,0.80,0.90,1.01};\n",
"Float_t y2[] = {2.1,3.86,7,9,10,10.55,9.64,7.26,5.42,2};\n",
"Float_t ex2[] = {.04,.12,.08,.06,.05,.04,.07,.06,.08,.04};\n",
"Float_t ey2[] = {.6,.8,.7,.4,.3,.3,.4,.5,.6,.7};\n",
"auto gr2 = new TGraphErrors(n2,x2,y2,ex2,ey2);\n",
"gr2->SetMarkerColor(kRed);\n",
"gr2->SetMarkerStyle(20);\n",
"\n",
"gr2->Fit(\"pol5\",\"q\");\n",
"auto func2 = (TF1 *) gr2->GetListOfFunctions()->FindObject(\"pol5\");\n",
"func2->SetLineColor(kRed);\n",
"func2->SetLineStyle(2);"
]
},
{
"cell_type": "markdown",
"id": "89087baf",
"metadata": {},
"source": [
"Add the second graph to the multigraph"
]
},
{
"cell_type": "code",
"execution_count": 6,
"id": "4cd59cc3",
"metadata": {
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"shell.execute_reply": "2026-05-19T20:37:53.072854Z"
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},
"outputs": [],
"source": [
"mg->Add(gr2);\n",
"\n",
"mg->Draw(\"ap\");"
]
},
{
"cell_type": "markdown",
"id": "b5f3e2b3",
"metadata": {},
"source": [
"Force drawing of canvas to generate the fit TPaveStats"
]
},
{
"cell_type": "code",
"execution_count": 7,
"id": "26056247",
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"source": [
"c1->Update();\n",
"\n",
"auto stats1 = (TPaveStats*) gr1->GetListOfFunctions()->FindObject(\"stats\");\n",
"auto stats2 = (TPaveStats*) gr2->GetListOfFunctions()->FindObject(\"stats\");\n",
"\n",
"if (stats1 && stats2) {\n",
" stats1->SetTextColor(kBlue);\n",
" stats2->SetTextColor(kRed);\n",
" stats1->SetX1NDC(0.12); stats1->SetX2NDC(0.32); stats1->SetY1NDC(0.82);\n",
" stats2->SetX1NDC(0.72); stats2->SetX2NDC(0.92); stats2->SetY1NDC(0.75);\n",
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"metadata": {},
"source": [
"Draw all canvases "
]
},
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"source": [
"gROOT->GetListOfCanvases()->Draw()"
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