{
"cells": [
{
"cell_type": "markdown",
"id": "f14b7f25",
"metadata": {},
"source": [
"# hist014_TH1_cumulative\n",
"\n",
"\n",
"\n",
"\n",
"**Author:** M. Schiller \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."
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "a1f7cdd9",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:12:11.724101Z",
"iopub.status.busy": "2026-05-19T20:12:11.723990Z",
"iopub.status.idle": "2026-05-19T20:12:12.182338Z",
"shell.execute_reply": "2026-05-19T20:12:12.181878Z"
}
},
"outputs": [],
"source": [
"TH1 *h = new TH1D(\"h\", \"h\", 100, -5., 5.);\n",
"gRandom->SetSeed();\n",
"h->FillRandom(\"gaus\", 1u << 16);"
]
},
{
"cell_type": "markdown",
"id": "1546f2c6",
"metadata": {},
"source": [
"get the cumulative of h"
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "6443984d",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:12:12.194373Z",
"iopub.status.busy": "2026-05-19T20:12:12.194231Z",
"iopub.status.idle": "2026-05-19T20:12:12.398178Z",
"shell.execute_reply": "2026-05-19T20:12:12.397762Z"
}
},
"outputs": [],
"source": [
"TH1 *hc = h->GetCumulative();"
]
},
{
"cell_type": "markdown",
"id": "e2942cb4",
"metadata": {},
"source": [
"check that c has the \"right\" contents"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "0039166f",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:12:12.405449Z",
"iopub.status.busy": "2026-05-19T20:12:12.405289Z",
"iopub.status.idle": "2026-05-19T20:12:12.611936Z",
"shell.execute_reply": "2026-05-19T20:12:12.607641Z"
}
},
"outputs": [],
"source": [
"Double_t *integral = h->GetIntegral();\n",
"for (Int_t i = 1; i <= hc->GetNbinsX(); ++i) {\n",
" assert(std::abs(integral[i] * h->GetEntries() - hc->GetBinContent(i)) < 1e-7);\n",
"}"
]
},
{
"cell_type": "markdown",
"id": "832e2649",
"metadata": {},
"source": [
"draw histogram together with its cumulative distribution"
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "32b6f066",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:12:12.645266Z",
"iopub.status.busy": "2026-05-19T20:12:12.645106Z",
"iopub.status.idle": "2026-05-19T20:12:12.850943Z",
"shell.execute_reply": "2026-05-19T20:12:12.850564Z"
}
},
"outputs": [
{
"data": {
"text/html": [
"\n",
"\n",
"\n",
"
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"\n",
"\n",
"\n"
],
"text/plain": [
""
]
},
"metadata": {},
"output_type": "display_data"
}
],
"source": [
"TCanvas *c = new TCanvas;\n",
"c->Divide(1, 2);\n",
"c->cd(1);\n",
"h->Draw();\n",
"c->cd(2);\n",
"hc->Draw();\n",
"c->Update();"
]
},
{
"cell_type": "markdown",
"id": "255d322d",
"metadata": {},
"source": [
"Draw all canvases "
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "55bca871",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:12:12.863336Z",
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"shell.execute_reply": "2026-05-19T20:12:13.068635Z"
}
},
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{
"data": {
"text/html": [
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},
"metadata": {},
"output_type": "display_data"
}
],
"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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