go-hep.org/x/hep@v0.38.1/hbook/rootcnv/root_test.go

// Copyright ©2017 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.

package rootcnv_test

import (
	"bytes"
	"fmt"
	"log"
	"math/rand/v2"
	"reflect"
	"runtime"
	"testing"

	"github.com/google/go-cmp/cmp"
	"go-hep.org/x/hep/groot"
	"go-hep.org/x/hep/groot/rhist"
	"go-hep.org/x/hep/groot/rtypes"
	"go-hep.org/x/hep/hbook"
	"go-hep.org/x/hep/hbook/rootcnv"
	"go-hep.org/x/hep/hbook/yodacnv"
	"gonum.org/v1/gonum/stat/distuv"
)

func ExampleH1D() {
	f, err := groot.Open("testdata/gauss-h1.root")
	if err != nil {
		log.Fatal(err)
	}
	defer f.Close()

	obj, err := f.Get("h1d")
	if err != nil {
		log.Fatal(err)
	}

	var (
		root = obj.(*rhist.H1D)
		h    = rootcnv.H1D(root)
	)

	fmt.Printf("name:    %q\n", root.Name())
	fmt.Printf("mean:    %v\n", h.XMean())
	fmt.Printf("std-dev: %v\n", h.XStdDev())
	fmt.Printf("std-err: %v\n", h.XStdErr())

	// Output:
	// name:    "h1d"
	// mean:    0.028120158262930028
	// std-dev: 2.5450388861661377
	// std-err: 0.025447023184829384
}

func ExampleH2D() {
	f, err := groot.Open("testdata/gauss-h2.root")
	if err != nil {
		log.Fatal(err)
	}
	defer f.Close()

	obj, err := f.Get("h2d")
	if err != nil {
		log.Fatal(err)
	}

	var (
		root = obj.(*rhist.H2D)
		h    = rootcnv.H2D(root)
	)

	fmt.Printf("name:      %q\n", root.Name())
	fmt.Printf("x-mean:    %v\n", h.XMean())
	fmt.Printf("x-std-dev: %v\n", h.XStdDev())
	fmt.Printf("x-std-err: %v\n", h.XStdErr())
	fmt.Printf("y-mean:    %v\n", h.YMean())
	fmt.Printf("y-std-dev: %v\n", h.YStdDev())
	fmt.Printf("y-std-err: %v\n", h.YStdErr())

	// Output:
	// name:      "h2d"
	// x-mean:    -0.005792199729986178
	// x-std-dev: 2.270805729597938
	// x-std-err: 0.06540325772462689
	// y-mean:    0.8942018621292575
	// y-std-dev: 1.830794214602073
	// y-std-err: 0.05273014080318356
}

func ExampleS2D() {
	f, err := groot.Open("../../groot/testdata/graphs.root")
	if err != nil {
		log.Fatal(err)
	}
	defer f.Close()

	obj, err := f.Get("tgae")
	if err != nil {
		log.Fatal(err)
	}

	var (
		root = obj.(rhist.GraphErrors)
		g    = rootcnv.S2D(root)
	)

	fmt.Printf("name:  %q\n", g.Annotation()["name"])
	fmt.Printf("title: %q\n", g.Annotation()["title"])
	fmt.Printf("#pts:  %v\n", g.Len())
	for i, pt := range g.Points() {
		x := pt.X
		y := pt.Y
		xlo := pt.ErrX.Min
		xhi := pt.ErrX.Max
		ylo := pt.ErrY.Min
		yhi := pt.ErrY.Max
		fmt.Printf("(x,y)[%d] = (%+e +/- [%+e, %+e], %+e +/- [%+e, %+e])\n", i, x, xlo, xhi, y, ylo, yhi)
	}

	// Output:
	// name:  "tgae"
	// title: "graph with asymmetric errors"
	// #pts:  4
	// (x,y)[0] = (+1.000000e+00 +/- [+1.000000e-01, +2.000000e-01], +2.000000e+00 +/- [+3.000000e-01, +4.000000e-01])
	// (x,y)[1] = (+2.000000e+00 +/- [+2.000000e-01, +4.000000e-01], +4.000000e+00 +/- [+6.000000e-01, +8.000000e-01])
	// (x,y)[2] = (+3.000000e+00 +/- [+3.000000e-01, +6.000000e-01], +6.000000e+00 +/- [+9.000000e-01, +1.200000e+00])
	// (x,y)[3] = (+4.000000e+00 +/- [+4.000000e-01, +8.000000e-01], +8.000000e+00 +/- [+1.200000e+00, +1.600000e+00])
}

func TestH1D(t *testing.T) {
	f, err := groot.Open("testdata/gauss-h1.root")
	if err != nil {
		t.Fatal(err)
	}
	defer f.Close()

	for _, test := range []struct {
		name string
		want []byte
	}{
		{
			name: "h1d",
			want: []byte(`BEGIN YODA_HISTO1D_V2 /h1d
Path: /h1d
Title: h1d
Type: Histo1D
---
# Mean: 2.812016e-02
# Area: 1.100600e+04
# ID	 ID	 sumw	 sumw2	 sumwx	 sumwx2	 numEntries
Total   	Total   	1.100600e+04	1.211000e+04	3.094905e+02	7.128989e+04	1.000400e+04
Underflow	Underflow	2.000000e+00	2.000000e+00	0.000000e+00	0.000000e+00	2.000000e+00
Overflow	Overflow	4.000000e+00	8.000000e+00	0.000000e+00	0.000000e+00	2.000000e+00
# xlow	 xhigh	 sumw	 sumw2	 sumwx	 sumwx2	 numEntries
-4.000000e+00	-3.200000e+00	6.600000e+00	7.260000e+00	0.000000e+00	0.000000e+00	6.000000e+00
-3.200000e+00	-2.400000e+00	7.260000e+01	7.986000e+01	0.000000e+00	0.000000e+00	6.600000e+01
-2.400000e+00	-1.600000e+00	5.434000e+02	5.977400e+02	0.000000e+00	0.000000e+00	4.940000e+02
-1.600000e+00	-8.000000e-01	1.708300e+03	1.879130e+03	0.000000e+00	0.000000e+00	1.553000e+03
-8.000000e-01	2.220446e-16	3.130600e+03	3.443660e+03	0.000000e+00	0.000000e+00	2.846000e+03
0.000000e+00	8.000000e-01	3.136100e+03	3.449710e+03	0.000000e+00	0.000000e+00	2.851000e+03
8.000000e-01	1.600000e+00	1.753400e+03	1.928740e+03	0.000000e+00	0.000000e+00	1.594000e+03
1.600000e+00	2.400000e+00	5.401000e+02	5.941100e+02	0.000000e+00	0.000000e+00	4.910000e+02
2.400000e+00	3.200000e+00	1.012000e+02	1.113200e+02	0.000000e+00	0.000000e+00	9.200000e+01
3.200000e+00	4.000000e+00	7.700000e+00	8.470000e+00	0.000000e+00	0.000000e+00	7.000000e+00
END YODA_HISTO1D_V2

`),
		},
		{
			name: "h1f",
			want: []byte(`BEGIN YODA_HISTO1D_V2 /h1f
Path: /h1f
Title: h1f
Type: Histo1D
---
# Mean: 2.812016e-02
# Area: 1.100600e+04
# ID	 ID	 sumw	 sumw2	 sumwx	 sumwx2	 numEntries
Total   	Total   	1.100600e+04	1.211000e+04	3.094905e+02	7.128989e+04	1.000400e+04
Underflow	Underflow	2.000000e+00	2.000000e+00	0.000000e+00	0.000000e+00	2.000000e+00
Overflow	Overflow	4.000000e+00	8.000000e+00	0.000000e+00	0.000000e+00	2.000000e+00
# xlow	 xhigh	 sumw	 sumw2	 sumwx	 sumwx2	 numEntries
-4.000000e+00	-3.200000e+00	6.600000e+00	7.260000e+00	0.000000e+00	0.000000e+00	6.000000e+00
-3.200000e+00	-2.400000e+00	7.259995e+01	7.986000e+01	0.000000e+00	0.000000e+00	6.600000e+01
-2.400000e+00	-1.600000e+00	5.434013e+02	5.977400e+02	0.000000e+00	0.000000e+00	4.940000e+02
-1.600000e+00	-8.000000e-01	1.708276e+03	1.879130e+03	0.000000e+00	0.000000e+00	1.553000e+03
-8.000000e-01	2.220446e-16	3.130664e+03	3.443660e+03	0.000000e+00	0.000000e+00	2.846000e+03
0.000000e+00	8.000000e-01	3.136165e+03	3.449710e+03	0.000000e+00	0.000000e+00	2.851000e+03
8.000000e-01	1.600000e+00	1.753375e+03	1.928740e+03	0.000000e+00	0.000000e+00	1.594000e+03
1.600000e+00	2.400000e+00	5.401014e+02	5.941100e+02	0.000000e+00	0.000000e+00	4.910000e+02
2.400000e+00	3.200000e+00	1.011999e+02	1.113200e+02	0.000000e+00	0.000000e+00	9.200000e+01
3.200000e+00	4.000000e+00	7.700000e+00	8.470000e+00	0.000000e+00	0.000000e+00	7.000000e+00
END YODA_HISTO1D_V2

`),
		},
		{
			name: "h1d-var",
			want: []byte(`BEGIN YODA_HISTO1D_V2 /h1d-var
Path: /h1d-var
Title: h1d-var
Type: Histo1D
---
# Mean: 2.812016e-02
# Area: 1.100600e+04
# ID	 ID	 sumw	 sumw2	 sumwx	 sumwx2	 numEntries
Total   	Total   	1.100600e+04	1.211000e+04	3.094905e+02	7.128989e+04	1.000400e+04
Underflow	Underflow	2.000000e+00	2.000000e+00	0.000000e+00	0.000000e+00	2.000000e+00
Overflow	Overflow	4.000000e+00	8.000000e+00	0.000000e+00	0.000000e+00	2.000000e+00
# xlow	 xhigh	 sumw	 sumw2	 sumwx	 sumwx2	 numEntries
-4.000000e+00	-3.200000e+00	6.600000e+00	7.260000e+00	0.000000e+00	0.000000e+00	6.000000e+00
-3.200000e+00	-2.400000e+00	7.259995e+01	7.986000e+01	0.000000e+00	0.000000e+00	6.600000e+01
-2.400000e+00	-1.600000e+00	5.434013e+02	5.977400e+02	0.000000e+00	0.000000e+00	4.940000e+02
-1.600000e+00	-8.000000e-01	1.708276e+03	1.879130e+03	0.000000e+00	0.000000e+00	1.553000e+03
-8.000000e-01	0.000000e+00	3.130664e+03	3.443660e+03	0.000000e+00	0.000000e+00	2.846000e+03
0.000000e+00	8.000000e-01	3.136165e+03	3.449710e+03	0.000000e+00	0.000000e+00	2.851000e+03
8.000000e-01	1.600000e+00	1.753375e+03	1.928740e+03	0.000000e+00	0.000000e+00	1.594000e+03
1.600000e+00	2.400000e+00	5.401014e+02	5.941100e+02	0.000000e+00	0.000000e+00	4.910000e+02
2.400000e+00	3.200000e+00	1.011999e+02	1.113200e+02	0.000000e+00	0.000000e+00	9.200000e+01
3.200000e+00	4.000000e+00	7.700000e+00	8.470000e+00	0.000000e+00	0.000000e+00	7.000000e+00
END YODA_HISTO1D_V2

`),
		},
		{
			name: "h1f-var",
			want: []byte(`BEGIN YODA_HISTO1D_V2 /h1f-var
Path: /h1f-var
Title: h1f-var
Type: Histo1D
---
# Mean: 2.812016e-02
# Area: 1.100600e+04
# ID	 ID	 sumw	 sumw2	 sumwx	 sumwx2	 numEntries
Total   	Total   	1.100600e+04	1.211000e+04	3.094905e+02	7.128989e+04	1.000400e+04
Underflow	Underflow	2.000000e+00	2.000000e+00	0.000000e+00	0.000000e+00	2.000000e+00
Overflow	Overflow	4.000000e+00	8.000000e+00	0.000000e+00	0.000000e+00	2.000000e+00
# xlow	 xhigh	 sumw	 sumw2	 sumwx	 sumwx2	 numEntries
-4.000000e+00	-3.200000e+00	6.600000e+00	7.260000e+00	0.000000e+00	0.000000e+00	6.000000e+00
-3.200000e+00	-2.400000e+00	7.259995e+01	7.986000e+01	0.000000e+00	0.000000e+00	6.600000e+01
-2.400000e+00	-1.600000e+00	5.434013e+02	5.977400e+02	0.000000e+00	0.000000e+00	4.940000e+02
-1.600000e+00	-8.000000e-01	1.708276e+03	1.879130e+03	0.000000e+00	0.000000e+00	1.553000e+03
-8.000000e-01	0.000000e+00	3.130664e+03	3.443660e+03	0.000000e+00	0.000000e+00	2.846000e+03
0.000000e+00	8.000000e-01	3.136165e+03	3.449710e+03	0.000000e+00	0.000000e+00	2.851000e+03
8.000000e-01	1.600000e+00	1.753375e+03	1.928740e+03	0.000000e+00	0.000000e+00	1.594000e+03
1.600000e+00	2.400000e+00	5.401014e+02	5.941100e+02	0.000000e+00	0.000000e+00	4.910000e+02
2.400000e+00	3.200000e+00	1.011999e+02	1.113200e+02	0.000000e+00	0.000000e+00	9.200000e+01
3.200000e+00	4.000000e+00	7.700000e+00	8.470000e+00	0.000000e+00	0.000000e+00	7.000000e+00
END YODA_HISTO1D_V2

`),
		},
	} {
		t.Run(test.name, func(t *testing.T) {
			obj, err := f.Get(test.name)
			if err != nil {
				t.Fatalf("error: %+v", err)
			}

			var (
				rhisto = obj.(rhist.H1)
				h      = rootcnv.H1D(rhisto)
				buf    = new(bytes.Buffer)
			)

			err = yodacnv.Write(buf, h)
			if err != nil {
				t.Fatalf("YODA error: %+v", err)
			}

			if !reflect.DeepEqual(buf.Bytes(), test.want) {
				fatalf := t.Fatalf
				if runtime.GOOS == "darwin" {
					fatalf = t.Logf
				}
				fatalf("invalid h1:\n%s",
					cmp.Diff(
						string(test.want),
						buf.String(),
					),
				)
			}
		})
	}
}

func TestH2D(t *testing.T) {
	f, err := groot.Open("testdata/gauss-h2.root")
	if err != nil {
		t.Fatal(err)
	}
	defer f.Close()

	for _, test := range []struct {
		name string
		want []byte
	}{
		{
			name: "h2f",
			want: []byte(`BEGIN YODA_HISTO2D_V2 /h2f
Path: /h2f
Title: h2f
Type: Histo2D
---
# Mean: (-5.792200e-03, 8.942019e-01)
# Volume: 1.083600e+04
# ID	 ID	 sumw	 sumw2	 sumwx	 sumwx2	 sumwy	 sumwy2	 sumwxy	 numEntries
Total   	Total   	1.083600e+04	9.740400e+04	-6.276428e+01	5.583048e+04	9.689571e+03	4.495449e+04	-1.878975e+02	1.000800e+04
# 2D outflow persistency not currently supported until API is stable
# xlow	 xhigh	 ylow	 yhigh	 sumw	 sumw2	 sumwx	 sumwx2	 sumwy	 sumwy2	 sumwxy	 numEntries
0.000000e+00	1.000000e+00	0.000000e+00	1.000000e+00	5.010000e+02	5.010000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	5.010000e+02
0.000000e+00	1.000000e+00	1.000000e+00	2.000000e+00	4.880000e+02	4.880000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	4.880000e+02
0.000000e+00	1.000000e+00	2.000000e+00	3.000000e+00	3.140000e+02	3.140000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	3.140000e+02
1.000000e+00	2.000000e+00	0.000000e+00	1.000000e+00	3.850000e+02	3.850000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	3.850000e+02
1.000000e+00	2.000000e+00	1.000000e+00	2.000000e+00	3.790000e+02	3.790000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	3.790000e+02
1.000000e+00	2.000000e+00	2.000000e+00	3.000000e+00	2.210000e+02	2.210000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	2.210000e+02
2.000000e+00	3.000000e+00	0.000000e+00	1.000000e+00	2.280000e+02	2.280000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	2.280000e+02
2.000000e+00	3.000000e+00	1.000000e+00	2.000000e+00	2.320000e+02	2.320000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	2.320000e+02
2.000000e+00	3.000000e+00	2.000000e+00	3.000000e+00	1.640000e+02	1.640000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	1.640000e+02
END YODA_HISTO2D_V2

`),
		},
		{
			name: "h2d",
			want: []byte(`BEGIN YODA_HISTO2D_V2 /h2d
Path: /h2d
Title: h2d
Type: Histo2D
---
# Mean: (-5.792200e-03, 8.942019e-01)
# Volume: 1.083600e+04
# ID	 ID	 sumw	 sumw2	 sumwx	 sumwx2	 sumwy	 sumwy2	 sumwxy	 numEntries
Total   	Total   	1.083600e+04	9.740400e+04	-6.276428e+01	5.583048e+04	9.689571e+03	4.495449e+04	-1.878975e+02	1.000800e+04
# 2D outflow persistency not currently supported until API is stable
# xlow	 xhigh	 ylow	 yhigh	 sumw	 sumw2	 sumwx	 sumwx2	 sumwy	 sumwy2	 sumwxy	 numEntries
0.000000e+00	1.000000e+00	0.000000e+00	1.000000e+00	5.010000e+02	5.010000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	5.010000e+02
0.000000e+00	1.000000e+00	1.000000e+00	2.000000e+00	4.880000e+02	4.880000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	4.880000e+02
0.000000e+00	1.000000e+00	2.000000e+00	3.000000e+00	3.140000e+02	3.140000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	3.140000e+02
1.000000e+00	2.000000e+00	0.000000e+00	1.000000e+00	3.850000e+02	3.850000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	3.850000e+02
1.000000e+00	2.000000e+00	1.000000e+00	2.000000e+00	3.790000e+02	3.790000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	3.790000e+02
1.000000e+00	2.000000e+00	2.000000e+00	3.000000e+00	2.210000e+02	2.210000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	2.210000e+02
2.000000e+00	3.000000e+00	0.000000e+00	1.000000e+00	2.280000e+02	2.280000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	2.280000e+02
2.000000e+00	3.000000e+00	1.000000e+00	2.000000e+00	2.320000e+02	2.320000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	2.320000e+02
2.000000e+00	3.000000e+00	2.000000e+00	3.000000e+00	1.640000e+02	1.640000e+02	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	1.640000e+02
END YODA_HISTO2D_V2

`),
		},
	} {
		t.Run(test.name, func(t *testing.T) {
			obj, err := f.Get(test.name)
			if err != nil {
				t.Fatalf("error: %+v", err)
			}
			var (
				rhisto = obj.(rhist.H2)
				h      = rootcnv.H2D(rhisto)
				buf    = new(bytes.Buffer)
			)

			err = yodacnv.Write(buf, h)
			if err != nil {
				t.Fatalf("YODA error: %+v", err)
			}

			if !reflect.DeepEqual(buf.Bytes(), test.want) {
				t.Fatalf("invalid h2d:\n%s",
					cmp.Diff(
						string(test.want),
						buf.String(),
					),
				)
			}
		})
	}
}

func TestFromH1D(t *testing.T) {
	const npoints = 10000

	// Create a normal distribution.
	dist := distuv.Normal{
		Mu:    0,
		Sigma: 1,
		Src:   rand.New(rand.NewPCG(0, 0)),
	}

	// Draw some random values from the standard
	// normal distribution.
	h := hbook.NewH1D(20, -4, +4)
	for range npoints {
		v := dist.Rand()
		h.Fill(v, 1)
	}
	h.Fill(-10, 1) // fill underflow
	h.Fill(-20, 2)
	h.Fill(+10, 1) // fill overflow
	h.Fill(+10, 2)
	h.Annotation()["name"] = "my-name"
	h.Annotation()["title"] = "my-title"

	for _, tc := range []struct {
		name   string
		h1     rhist.H1
		sumw   float64
		sumw2  float64
		sumwx  float64
		sumwx2 float64
	}{
		{
			name:   "TH1D",
			h1:     rootcnv.FromH1D(h),
			sumw:   h.SumW(),
			sumw2:  h.SumW2(),
			sumwx:  h.SumWX(),
			sumwx2: h.SumWX2(),
		},
	} {
		t.Run(tc.name, func(t *testing.T) {
			if got, want := tc.h1.SumW(), h.SumW(); got != want {
				t.Fatalf("sumw: got=%v, want=%v", got, want)
			}
			if got, want := tc.h1.SumW2(), h.SumW2(); got != want {
				t.Fatalf("sumw2: got=%v, want=%v", got, want)
			}
			if got, want := tc.h1.SumWX(), h.SumWX(); got != want {
				t.Fatalf("sumwx: got=%v, want=%v", got, want)
			}
			if got, want := tc.h1.SumWX2(), h.SumWX2(); got != want {
				t.Fatalf("sumwx2: got=%v, want=%v", got, want)
			}

			rraw, err := tc.h1.(yodacnv.Marshaler).MarshalYODA()
			if err != nil {
				t.Fatal(err)
			}

			hh := rootcnv.H1D(tc.h1)

			hraw, err := hh.MarshalYODA()
			if err != nil {
				t.Fatal(err)
			}

			var hr = rtypes.Factory.Get(tc.name)().Interface().(rhist.H1)
			if err := hr.(yodacnv.Unmarshaler).UnmarshalYODA(hraw); err != nil {
				t.Fatal(err)
			}

			rgot, err := hr.(yodacnv.Marshaler).MarshalYODA()
			if err != nil {
				t.Fatal(err)
			}

			if !bytes.Equal(rgot, rraw) {
				t.Fatalf("round trip error:\nraw:\n%s\ngot:\n%s\n", rraw, rgot)
			}
		})
	}
}

func TestFromH2D(t *testing.T) {
	const npoints = 10000

	// Create a normal distribution.
	dist := distuv.Normal{
		Mu:    0,
		Sigma: 1,
		Src:   rand.New(rand.NewPCG(0, 0)),
	}

	// Draw some random values from the standard
	// normal distribution.
	h := hbook.NewH2D(5, -4, +4, 6, -4, +4)
	for range npoints {
		x := dist.Rand()
		y := dist.Rand()
		h.Fill(x, y, 1)
	}
	h.Fill(+0, +5, 1) // N
	h.Fill(-5, +5, 2) // N-W
	h.Fill(-5, +0, 3) // W
	h.Fill(-5, -5, 4) // S-W
	h.Fill(+0, -5, 5) // S
	h.Fill(+5, -5, 6) // S-E
	h.Fill(+5, +0, 7) // E
	h.Fill(+5, +5, 8) // N-E

	h.Annotation()["name"] = "my-name"
	h.Annotation()["title"] = "my-title"

	for _, tc := range []struct {
		name   string
		h2     rhist.H2
		sumw   float64
		sumw2  float64
		sumwx  float64
		sumwx2 float64
	}{
		{
			name:   "TH2D",
			h2:     rootcnv.FromH2D(h),
			sumw:   h.SumW(),
			sumw2:  h.SumW2(),
			sumwx:  h.SumWX(),
			sumwx2: h.SumWX2(),
		},
	} {
		t.Run(tc.name, func(t *testing.T) {
			if got, want := tc.h2.SumW(), h.SumW(); got != want {
				t.Fatalf("sumw: got=%v, want=%v", got, want)
			}
			if got, want := tc.h2.SumW2(), h.SumW2(); got != want {
				t.Fatalf("sumw2: got=%v, want=%v", got, want)
			}
			if got, want := tc.h2.SumWX(), h.SumWX(); got != want {
				t.Fatalf("sumwx: got=%v, want=%v", got, want)
			}
			if got, want := tc.h2.SumWX2(), h.SumWX2(); got != want {
				t.Fatalf("sumwx2: got=%v, want=%v", got, want)
			}

			rraw, err := tc.h2.(yodacnv.Marshaler).MarshalYODA()
			if err != nil {
				t.Fatal(err)
			}

			hh := rootcnv.H2D(tc.h2)

			hraw, err := hh.MarshalYODA()
			if err != nil {
				t.Fatal(err)
			}

			var hr = rtypes.Factory.Get(tc.name)().Interface().(rhist.H2)
			if err := hr.(yodacnv.Unmarshaler).UnmarshalYODA(hraw); err != nil {
				t.Fatal(err)
			}

			rgot, err := hr.(yodacnv.Marshaler).MarshalYODA()
			if err != nil {
				t.Fatal(err)
			}

			// rounding errors... // FIXME(sbinet)
			rraw = bytes.Replace(rraw,
				[]byte("# Mean: (1.990041e-02, 2.039840e-04)"),
				[]byte("# Mean: (1.990041e-02, 2.039841e-04)"),
				-1,
			)
			if !bytes.Equal(rgot, rraw) {
				t.Fatalf("round trip error:\n%s\n",
					cmp.Diff(
						string(rraw),
						string(rgot),
					),
				)
			}
		})
	}
}

func TestFromS2D(t *testing.T) {
	hg := hbook.NewS2D(
		hbook.Point2D{X: 1, Y: 1, ErrX: hbook.Range{Min: 1, Max: 2}, ErrY: hbook.Range{Min: 3, Max: 4}},
		hbook.Point2D{X: 2, Y: 1.5, ErrX: hbook.Range{Min: 1, Max: 2}, ErrY: hbook.Range{Min: 3, Max: 4}},
		hbook.Point2D{X: -1, Y: +2, ErrX: hbook.Range{Min: 1, Max: 2}, ErrY: hbook.Range{Min: 3, Max: 4}},
	)

	rg := rootcnv.FromS2D(hg)

	hr := rootcnv.S2D(rg)

	want, err := hg.MarshalYODA()
	if err != nil {
		t.Fatal(err)
	}

	got, err := hr.MarshalYODA()
	if err != nil {
		t.Fatal(err)
	}

	if !bytes.Equal(got, want) {
		t.Fatalf("invalid s2d:\n%s",
			cmp.Diff(
				string(want),
				string(got),
			),
		)
	}
}