{
"cells": [
{
"cell_type": "markdown",
"id": "969b5240",
"metadata": {},
"source": [
"# qa2\n",
"Test generation of random numbers distributed according to a function defined by the user.\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 08:27 PM."
]
},
{
"cell_type": "markdown",
"id": "2c8f8913",
"metadata": {},
"source": [
"Fill a 1-D histogram from a parametric function"
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "dafa0e15",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:27:14.807555Z",
"iopub.status.busy": "2026-05-19T20:27:14.807444Z",
"iopub.status.idle": "2026-05-19T20:27:15.157334Z",
"shell.execute_reply": "2026-05-19T20:27:15.156750Z"
}
},
"outputs": [],
"source": [
"TCanvas *c1 = new TCanvas(\"c1\",\"The FillRandom example\",0,0,700,500);\n",
"\n",
"gBenchmark->Start(\"fillrandom\");"
]
},
{
"cell_type": "markdown",
"id": "1f3b578e",
"metadata": {},
"source": [
"A function (any dimension) or a formula may reference\n",
"an already defined formula"
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "53d8ee78",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:27:15.159325Z",
"iopub.status.busy": "2026-05-19T20:27:15.159202Z",
"iopub.status.idle": "2026-05-19T20:27:15.366206Z",
"shell.execute_reply": "2026-05-19T20:27:15.365666Z"
}
},
"outputs": [],
"source": [
"TFormula *form1 = new TFormula(\"form1\",\"abs(sin(x)/x)\");\n",
"TF1 *sqroot = new TF1(\"sqroot\",\"x*gaus(0) + [3]*form1\",0,10);\n",
"sqroot->SetParameters(10,4,1,20);"
]
},
{
"cell_type": "markdown",
"id": "baec7f4d",
"metadata": {},
"source": [
"Create a one dimensional histogram (one float per bin)\n",
"and fill it following the distribution in function sqroot."
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "68466a00",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:27:15.368080Z",
"iopub.status.busy": "2026-05-19T20:27:15.367965Z",
"iopub.status.idle": "2026-05-19T20:27:15.574810Z",
"shell.execute_reply": "2026-05-19T20:27:15.574275Z"
}
},
"outputs": [
{
"data": {
"text/html": [
"\n",
"\n",
"\n",
"
\n",
"\n",
"\n",
"\n"
],
"text/plain": [
""
]
},
"metadata": {},
"output_type": "display_data"
}
],
"source": [
"TH1F *h1f = new TH1F(\"h1f\",\"Test random numbers\",200,0,10);\n",
"h1f->SetFillColor(45);\n",
"h1f->FillRandom(\"sqroot\",100000);\n",
"h1f->Draw();\n",
"TPaveLabel *lfunction = new TPaveLabel(5,39,9.8,46,\"The sqroot function\");\n",
"lfunction->SetFillColor(41);\n",
"\n",
"c1->SetGridx();\n",
"c1->SetGridy();\n",
"\n",
"h1f->SetDirectory(nullptr);\n",
"\n",
"c1->Update();\n",
"\n",
"sqroot->SetParameters(200,4,1,20);"
]
},
{
"cell_type": "markdown",
"id": "d1a49287",
"metadata": {},
"source": [
"Draw all canvases "
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "979d1449",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:27:15.576294Z",
"iopub.status.busy": "2026-05-19T20:27:15.576177Z",
"iopub.status.idle": "2026-05-19T20:27:15.787792Z",
"shell.execute_reply": "2026-05-19T20:27:15.787221Z"
}
},
"outputs": [
{
"data": {
"text/html": [
"\n",
"\n",
"\n",
"
\n",
"\n",
"\n",
"\n"
],
"text/plain": [
""
]
},
"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++"
}
},
"nbformat": 4,
"nbformat_minor": 5
}