{
"cells": [
{
"cell_type": "markdown",
"id": "21874269",
"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 Sunday, December 21, 2025 at 02:49 PM."
]
},
{
"cell_type": "markdown",
"id": "adb28949",
"metadata": {},
"source": [
"Fill a 1-D histogram from a parametric function"
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "a0aac945",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2025-12-21T13:49:27.445485Z",
"iopub.status.busy": "2025-12-21T13:49:27.445361Z",
"iopub.status.idle": "2025-12-21T13:49:27.858436Z",
"shell.execute_reply": "2025-12-21T13:49:27.842504Z"
}
},
"outputs": [],
"source": [
"TCanvas *c1 = new TCanvas(\"c1\",\"The FillRandom example\",0,0,700,500);\n",
"\n",
"gBenchmark->Start(\"fillrandom\");"
]
},
{
"cell_type": "markdown",
"id": "7bec3935",
"metadata": {},
"source": [
"A function (any dimension) or a formula may reference\n",
"an already defined formula"
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "d0dc0c18",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2025-12-21T13:49:27.879842Z",
"iopub.status.busy": "2025-12-21T13:49:27.879635Z",
"iopub.status.idle": "2025-12-21T13:49:28.092958Z",
"shell.execute_reply": "2025-12-21T13:49:28.092399Z"
}
},
"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": "7a820221",
"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": "206ea1b4",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2025-12-21T13:49:28.097773Z",
"iopub.status.busy": "2025-12-21T13:49:28.097633Z",
"iopub.status.idle": "2025-12-21T13:49:28.305133Z",
"shell.execute_reply": "2025-12-21T13:49:28.304594Z"
}
},
"outputs": [
{
"data": {
"text/html": [
"\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": "88a47c84",
"metadata": {},
"source": [
"Draw all canvases "
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "19d42b3f",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2025-12-21T13:49:28.306886Z",
"iopub.status.busy": "2025-12-21T13:49:28.306752Z",
"iopub.status.idle": "2025-12-21T13:49:28.523649Z",
"shell.execute_reply": "2025-12-21T13:49:28.523236Z"
}
},
"outputs": [
{
"data": {
"text/html": [
"\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
}