{
"cells": [
{
"cell_type": "markdown",
"id": "726d6938",
"metadata": {},
"source": [
"# hsimple\n",
" This program creates :\n",
" - a one dimensional histogram\n",
" - a two dimensional histogram\n",
" - a profile histogram\n",
" - a memory-resident ntuple\n",
"\n",
" These objects are filled with some random numbers and saved on a file.\n",
"\n",
"\n",
"\n",
"\n",
"**Author:** Vincenzo Eduardo Padulano (CERN), 09.2025 \n",
"This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, May 19, 2026 at 08:07 PM."
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "cd0c2398",
"metadata": {
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"execution": {
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"shell.execute_reply": "2026-05-19T20:07:37.060441Z"
}
},
"outputs": [],
"source": [
"import numpy\n",
"from ROOT import TH1F, TH2F, TCanvas, TFile, TNtuple, TProfile, gBenchmark, gSystem"
]
},
{
"cell_type": "markdown",
"id": "88ce7093",
"metadata": {},
"source": [
"Create a new canvas, and customize it."
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "d5ec9075",
"metadata": {
"collapsed": false,
"execution": {
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"outputs": [],
"source": [
"c1 = TCanvas(\"c1\", \"Dynamic Filling Example\", 200, 10, 700, 500)\n",
"c1.SetFillColor(42)\n",
"frame = c1.GetFrame()\n",
"frame.SetFillColor(21)\n",
"frame.SetBorderSize(6)\n",
"frame.SetBorderMode(-1)"
]
},
{
"cell_type": "markdown",
"id": "1d7ab37b",
"metadata": {},
"source": [
"Create some histograms, a profile histogram and an ntuple"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "1bbc86db",
"metadata": {
"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:07:37.332474Z"
}
},
"outputs": [],
"source": [
"hpx = TH1F(\"hpx\", \"This is the px distribution\", 100, -4, 4)\n",
"hpxpy = TH2F(\"hpxpy\", \"py vs px\", 40, -4, 4, 40, -4, 4)\n",
"hprof = TProfile(\"hprof\", \"Profile of pz versus px\", 100, -4, 4, 0, 20)\n",
"ntuple = TNtuple(\"ntuple\", \"Demo ntuple\", \"px:py:pz:random:i\")"
]
},
{
"cell_type": "markdown",
"id": "b0c31273",
"metadata": {},
"source": [
"Set canvas/frame attributes."
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "27e219f2",
"metadata": {
"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:07:37.441917Z"
}
},
"outputs": [],
"source": [
"hpx.SetFillColor(48)\n",
"\n",
"gBenchmark.Start(\"hsimple\")"
]
},
{
"cell_type": "markdown",
"id": "6847d71b",
"metadata": {},
"source": [
"Fill histograms randomly."
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "983d011e",
"metadata": {
"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:07:37.854988Z"
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},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"hsimple : Real Time = 0.34 seconds Cpu Time = 0.24 seconds\n"
]
},
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"source": [
"for i in range(25000):\n",
" # Retrieve the generated values\n",
" px, py = numpy.random.standard_normal(size=2)\n",
"\n",
" pz = px * px + py * py\n",
" random = numpy.random.rand()\n",
"\n",
" # Fill histograms.\n",
" hpx.Fill(px)\n",
" hpxpy.Fill(px, py)\n",
" hprof.Fill(px, pz)\n",
" ntuple.Fill(px, py, pz, random, i)\n",
"\n",
" # Update display every 1000 events.\n",
" if i > 0 and i % 1000 == 0:\n",
" hpx.Draw()\n",
"\n",
" c1.Modified()\n",
" c1.Update()\n",
"\n",
" if gSystem.ProcessEvents(): # allow user interrupt\n",
" break\n",
"\n",
"gBenchmark.Show(\"hsimple\")"
]
},
{
"cell_type": "markdown",
"id": "9f2c6129",
"metadata": {},
"source": [
"Create a new ROOT binary machine independent file.\n",
"Note that this file may contain any kind of ROOT objects, histograms,\n",
"pictures, graphics objects, detector geometries, tracks, events, etc."
]
},
{
"cell_type": "code",
"execution_count": 6,
"id": "71dfce97",
"metadata": {
"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:07:38.025629Z"
}
},
"outputs": [],
"source": [
"with TFile(\"py-hsimple.root\", \"RECREATE\", \"Demo ROOT file with histograms\") as hfile:\n",
" # Save all created objects in the file\n",
" hfile.WriteObject(hpx)\n",
" hfile.WriteObject(hpxpy)\n",
" hfile.WriteObject(hprof)\n",
" # TNTuple is special because it is a TTree-derived class. To make sure all the\n",
" # dataset is properly written to disk, we connect it to the file and then\n",
" # we ask the ntuple to write all the information to the file itself.\n",
" ntuple.SetDirectory(hfile)\n",
" ntuple.Write()\n",
"\n",
"c1.Modified()\n",
"c1.Update()"
]
},
{
"cell_type": "markdown",
"id": "72d80582",
"metadata": {},
"source": [
"Draw all canvases "
]
},
{
"cell_type": "code",
"execution_count": 7,
"id": "81f18732",
"metadata": {
"collapsed": false,
"execution": {
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"metadata": {},
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],
"source": [
"%jsroot on\n",
"from ROOT import gROOT \n",
"gROOT.GetListOfCanvases().Draw()"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
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