errbars_example_test.go

Documentation: gonum.org/v1/plot/plotter

     1  // Copyright ©2015 The Gonum Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package plotter_test
     6  
     7  import (
     8  	"log"
     9  
    10  	"golang.org/x/exp/rand"
    11  
    12  	"gonum.org/v1/plot"
    13  	"gonum.org/v1/plot/plotter"
    14  	"gonum.org/v1/plot/vg/draw"
    15  )
    16  
    17  // ExampleErrors draws points and error bars.
    18  func ExampleErrors() {
    19  	rnd := rand.New(rand.NewSource(1))
    20  
    21  	randomError := func(n int) plotter.Errors {
    22  		err := make(plotter.Errors, n)
    23  		for i := range err {
    24  			err[i].Low = rnd.Float64()
    25  			err[i].High = rnd.Float64()
    26  		}
    27  		return err
    28  	}
    29  	// randomPoints returns some random x, y points
    30  	// with some interesting kind of trend.
    31  	randomPoints := func(n int) plotter.XYs {
    32  		pts := make(plotter.XYs, n)
    33  		for i := range pts {
    34  			if i == 0 {
    35  				pts[i].X = rnd.Float64()
    36  			} else {
    37  				pts[i].X = pts[i-1].X + rnd.Float64()
    38  			}
    39  			pts[i].Y = pts[i].X + 10*rnd.Float64()
    40  		}
    41  		return pts
    42  	}
    43  
    44  	type errPoints struct {
    45  		plotter.XYs
    46  		plotter.YErrors
    47  		plotter.XErrors
    48  	}
    49  
    50  	n := 15
    51  	data := errPoints{
    52  		XYs:     randomPoints(n),
    53  		YErrors: plotter.YErrors(randomError(n)),
    54  		XErrors: plotter.XErrors(randomError(n)),
    55  	}
    56  
    57  	p := plot.New()
    58  	scatter, err := plotter.NewScatter(data)
    59  	if err != nil {
    60  		log.Panic(err)
    61  	}
    62  	scatter.Shape = draw.CrossGlyph{}
    63  	xerrs, err := plotter.NewXErrorBars(data)
    64  	if err != nil {
    65  		log.Panic(err)
    66  	}
    67  	yerrs, err := plotter.NewYErrorBars(data)
    68  	if err != nil {
    69  		log.Panic(err)
    70  	}
    71  	p.Add(scatter, xerrs, yerrs)
    72  
    73  	err = p.Save(200, 200, "testdata/errorBars.png")
    74  	if err != nil {
    75  		log.Panic(err)
    76  	}
    77  }
    78
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