{
"cells": [
{
"cell_type": "markdown",
"id": "634a8cd3",
"metadata": {},
"source": [
"# gr002_errors\n",
"[gr03_err2gr.C](https://root.cern/doc/master/gerrors2_8C.html) tutorial\n",
"\n",
"See the [TGraphErrors documentation](https://root.cern/doc/master/classTGraphErrors.html)\n",
"\n",
"\n",
"\n",
"**Author:** Rene Brun, Jamie Gooding \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."
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "ed2f11e7",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:37:41.305253Z",
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"iopub.status.idle": "2026-05-19T20:37:42.456246Z",
"shell.execute_reply": "2026-05-19T20:37:42.455535Z"
}
},
"outputs": [],
"source": [
"import numpy as np\n",
"import ROOT\n",
"\n",
"c1 = ROOT.TCanvas(\"c1\", \"A Simple Graph with error bars\", 200, 10, 700, 500)\n",
"\n",
"c1.SetGrid()\n",
"c1.GetFrame().SetBorderSize(12)"
]
},
{
"cell_type": "markdown",
"id": "f3fada85",
"metadata": {},
"source": [
" We will use the constructor requiring: the number of points, arrays containing the x-and y-axis values, and arrays with the x- andy-axis errors"
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "db5695fd",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:37:42.459257Z",
"iopub.status.busy": "2026-05-19T20:37:42.459065Z",
"iopub.status.idle": "2026-05-19T20:37:42.584091Z",
"shell.execute_reply": "2026-05-19T20:37:42.583253Z"
}
},
"outputs": [],
"source": [
"n = 10\n",
"x = np.array([-0.22, 0.05, 0.25, 0.35, 0.5, 0.61, 0.7, 0.85, 0.89, 0.95])\n",
"y = np.array([1, 2.9, 5.6, 7.4, 9, 9.6, 8.7, 6.3, 4.5, 1])\n",
"ex = np.array([0.05, 0.1, 0.07, 0.07, 0.04, 0.05, 0.06, 0.07, 0.08, 0.05])\n",
"ey = np.array([0.8, 0.7, 0.6, 0.5, 0.4, 0.4, 0.5, 0.6, 0.7, 0.8])"
]
},
{
"cell_type": "markdown",
"id": "77c1e13e",
"metadata": {},
"source": [
"If all x-axis errors should zero, just provide a single 0 in place of ex"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "0e492cb8",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:37:42.586302Z",
"iopub.status.busy": "2026-05-19T20:37:42.586167Z",
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"shell.execute_reply": "2026-05-19T20:37:42.708084Z"
}
},
"outputs": [],
"source": [
"gr = ROOT.TGraphErrors(n, x, y, ex, ey)\n",
"\n",
"gr.SetTitle(\"TGraphErrors Example\")\n",
"gr.SetMarkerColor(4)\n",
"gr.SetMarkerStyle(21)"
]
},
{
"cell_type": "markdown",
"id": "e110c91b",
"metadata": {},
"source": [
"To draw in a new/empty canvas or pad, include the option \"A\" so that the axes are drawn (leave it out if the graph is to be drawn on top of an existing plot"
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "af378799",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:37:42.710886Z",
"iopub.status.busy": "2026-05-19T20:37:42.710716Z",
"iopub.status.idle": "2026-05-19T20:37:42.906154Z",
"shell.execute_reply": "2026-05-19T20:37:42.905062Z"
}
},
"outputs": [
{
"data": {
"text/html": [
"\n",
"\n",
"\n",
"
\n",
"\n",
"\n",
"\n"
],
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""
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"output_type": "display_data"
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],
"source": [
"gr.Draw(\"ALP\")\n",
"\n",
"c1.Update()"
]
},
{
"cell_type": "markdown",
"id": "b71d0efe",
"metadata": {},
"source": [
"Draw all canvases "
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "093d6095",
"metadata": {
"collapsed": false,
"execution": {
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"iopub.status.idle": "2026-05-19T20:37:43.023175Z",
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{
"data": {
"text/html": [
"\n",
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"\n",
"\n"
],
"text/plain": [
""
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},
"metadata": {},
"output_type": "display_data"
}
],
"source": [
"%jsroot on\n",
"from ROOT import gROOT \n",
"gROOT.GetListOfCanvases().Draw()"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
"name": "python3"
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"file_extension": ".py",
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