diff --git a/fit/run.go b/fit/run.go
deleted file mode 100644
index 0fc1eabd..00000000
--- a/fit/run.go
+++ /dev/null
@@ -1,172 +0,0 @@
-// Copyright ©2021 The go-hep Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build ignore
-
-package main
-
-import (
-	"bufio"
-	"fmt"
-	"image/color"
-	"log"
-	"math"
-	"os"
-	"strconv"
-	"strings"
-
-	"go-hep.org/x/hep/fit"
-	"go-hep.org/x/hep/hplot"
-	"gonum.org/v1/gonum/optimize"
-	"gonum.org/v1/plot"
-	"gonum.org/v1/plot/plotter"
-	"gonum.org/v1/plot/vg"
-)
-
-func fitFunc(x float64, p []float64) float64 {
-	return p[0]*math.Cos(2*math.Pi/p[1]*x+p[2]) + p[3]*x
-}
-
-func readXY(fname string) (xs, ys []float64) {
-	f, err := os.Open(fname)
-	if err != nil {
-		log.Fatal(err)
-	}
-	defer f.Close()
-
-	scan := bufio.NewScanner(f)
-	for scan.Scan() {
-		line := scan.Text()
-		toks := strings.Split(line, " ")
-		x, err := strconv.ParseFloat(toks[0], 64)
-		if err != nil {
-			log.Fatal(err)
-		}
-		xs = append(xs, x)
-
-		y, err := strconv.ParseFloat(toks[1], 64)
-		if err != nil {
-			log.Fatal(err)
-		}
-		ys = append(ys, y)
-	}
-
-	return
-}
-
-func main() {
-	curveFit()
-	ceresFit()
-}
-
-func curveFit() {
-	xdata, ydata := readXY("testdata/curve-data.txt")
-	log.Printf("fit(3): %v\n", efit(3, 2.5, 1.3))
-	fmt.Printf("--- LLS ---\n")
-	res, err := fit.Curve1D(
-		fit.Func1D{
-			F: func(x float64, ps []float64) float64 {
-				return efit(x, ps[0], ps[1])
-			},
-			N: 2,
-			X: xdata,
-			Y: ydata,
-		},
-		nil, &optimize.LBFGS{},
-	)
-	switch err {
-	case nil:
-		fmt.Printf("res.X: %v\n", res.X)
-		fmt.Printf("res.F: %v\n", res.F)
-		fmt.Printf("res.G: %v\n", res.Gradient)
-		fmt.Printf("res.H: %v\n", res.Hessian)
-		fmt.Printf("res.Stats: %+v\n", res.Stats)
-		fmt.Printf("fit(3): %v\n", efit(3, res.X[0], res.X[1]))
-	default:
-		fmt.Printf("err: %v\n", err)
-	}
-	{
-		p, err := plot.New()
-		if err != nil {
-			log.Fatal(err)
-		}
-		p.X.Label.Text = "x"
-		p.Y.Label.Text = "curve data"
-		p.Add(plotter.NewGrid())
-		s, err := plotter.NewScatter(hplot.ZipXY(xdata, ydata))
-		if err != nil {
-			log.Fatal(err)
-		}
-		s.Color = color.RGBA{255, 0, 0, 255}
-
-		p.Add(s)
-
-		f := plotter.NewFunction(func(x float64) float64 {
-			return efit(x, res.X[0], res.X[1])
-		})
-		f.Color = color.RGBA{0, 0, 255, 255}
-		p.Add(f)
-
-		p.Save(20*vg.Centimeter, 15*vg.Centimeter, "testdata/curve-plot.png")
-	}
-
-}
-
-func efit(x, a, b float64) float64 {
-	return a*math.Exp(-x) + b
-}
-
-func ceresFitFunc(x, a, b float64) float64 {
-	return math.Exp(a*x + b)
-}
-
-func ceresFit() {
-	xdata, ydata := readXY("testdata/ceres-data.txt")
-	fmt.Printf("--- Ceres FIT ---\n")
-	res, err := fit.Curve1D(
-		fit.Func1D{
-			F:  func(x float64, ps []float64) float64 { return ceresFitFunc(x, ps[0], ps[1]) },
-			X:  xdata,
-			Y:  ydata,
-			Ps: []float64{1, 1},
-		}, nil, nil,
-	)
-
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	fmt.Printf("res.Status: %v\n", res.Status)
-	fmt.Printf("res.X: %v\n", res.X)
-	fmt.Printf("res.F: %v\n", res.F)
-	fmt.Printf("res.G: %v\n", res.Gradient)
-	fmt.Printf("res.H: %v\n", res.Hessian)
-	fmt.Printf("res.Stats: %+v\n", res.Stats)
-
-	{
-		p, err := plot.New()
-		if err != nil {
-			log.Fatal(err)
-		}
-		p.X.Label.Text = "x"
-		p.Y.Label.Text = "ceres data"
-		p.Add(plotter.NewGrid())
-		s, err := plotter.NewScatter(hplot.ZipXY(xdata, ydata))
-		if err != nil {
-			log.Fatal(err)
-		}
-		s.Color = color.RGBA{255, 0, 0, 255}
-
-		p.Add(s)
-
-		f := plotter.NewFunction(func(x float64) float64 {
-			return ceresFitFunc(x, res.X[0], res.X[1])
-		})
-		f.Color = color.RGBA{0, 0, 255, 255}
-		p.Add(f)
-
-		p.Save(20*vg.Centimeter, 15*vg.Centimeter, "testdata/ceres-plot.png")
-	}
-
-}