base.SourceCloner. NB ExampleGridSearchCV fails.

base/source.go

@@ -3,21 +3,17 @@ package base
 import (
 	"sync"
 
-	"golang.org/x/exp/rand"
-
 	"github.com/pa-m/randomkit"
+	"golang.org/x/exp/rand"
 )
 
 // A Source represents a source of uniformly-distributed
 // pseudo-random int64 values in the range [0, 1<<64).
-type Source interface {
-	Uint64() uint64
-	Seed(seed uint64)
-}
+type Source = rand.Source
 
 // SourceCloner is an "golang.org/x/exp/rand".Source with a Clone method
 type SourceCloner interface {
-	Clone() rand.Source
+	SourceClone() Source
 }
 
 // RandomState represents a bit more than random_state pythonic attribute. it's not only a seed but a source with a state as it's name states
@@ -34,7 +30,14 @@ func NewSource(seed uint64) *randomkit.RKState {
 // It is just a standard Source with its operations protected by a sync.Mutex.
 type LockedSource struct {
 	lk  sync.Mutex
-	src Source
+	src *randomkit.RKState
+}
+
+// WithLock executes f while s is locked
+func (s *LockedSource) WithLock(f func(Source)) {
+	s.lk.Lock()
+	f(s.src)
+	s.lk.Unlock()
 }
 
 // Uint64 ...
@@ -52,9 +55,9 @@ func (s *LockedSource) Seed(seed uint64) {
 	s.lk.Unlock()
 }
 
-// Clone ...
-func (s *LockedSource) Clone() rand.Source {
-	return &LockedSource{src: s.src.(SourceCloner).Clone()}
+// SourceClone ...
+func (s *LockedSource) SourceClone() Source {
+	return &LockedSource{src: s.src.SourceClone().(*randomkit.RKState)}
 }
 
 // NewLockedSource returns a rand.Source safe for concurrent access
@@ -78,3 +81,13 @@ type NormFloat64er interface {
 type Intner interface {
 	Intn(int) int
 }
+
+// Permer is implemented by a random source having a method Perm(int) []int
+type Permer interface {
+	Perm(int) []int
+}
+
+// Shuffler  is implemented by a random source having a method Shuffle(int,func(int,int))
+type Shuffler interface {
+	Shuffler(int, func(int, int))
+}

base/source_test.go

@@ -17,7 +17,7 @@ var (
 
 func TestSource(t *testing.T) {
 	s := NewSource(7)
-	s2 := s.Clone()
+	s2 := s.SourceClone()
 	var a [5]float64
 	for i := range a {
 		a[i] = s.Float64()

gaussian_process/gpr.go

@@ -46,7 +46,7 @@ func (m *Regressor) IsClassifier() bool { return false }
 func (m *Regressor) PredicterClone() base.Predicter {
 	clone := *m
 	if cloner, ok := m.RandomState.(base.SourceCloner); ok {
-		clone.RandomState = cloner.Clone()
+		clone.RandomState = cloner.SourceClone()
 	}
 	if m.Xtrain != nil {
 		clone.Xtrain = mat.DenseCopyOf(m.Xtrain)

go.mod

@@ -8,11 +8,9 @@ require (
 	github.com/jung-kurt/gofpdf v1.10.1 // indirect
 	github.com/kr/pretty v0.1.0 // indirect
 	github.com/pa-m/optimize v0.0.0-20190612075243-15ee852a6d9a
-	github.com/pa-m/randomkit v0.0.0-20190612075210-f24d270692b4
+	github.com/pa-m/randomkit v0.0.0-20191001073902-db4fd80633df
 	github.com/pkg/errors v0.8.1
-	golang.org/x/exp v0.0.0-20190829153037-c13cbed26979
-	golang.org/x/image v0.0.0-20190902063713-cb417be4ba39 // indirect
-	golang.org/x/tools v0.0.0-20190905235650-93dcc2f048f5 // indirect
+	golang.org/x/exp v0.0.0-20191129062945-2f5052295587
 	gonum.org/v1/gonum v0.0.0-20190929233944-b20cf7805fc4
 	gonum.org/v1/plot v0.0.0-20190615073203-9aa86143727f
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect

go.sum

@@ -1,3 +1,4 @@
+dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802 h1:1BDTz0u9nC3//pOCMdNH+CiXJVYJh5UQNCOBG7jbELc=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/ajstarks/svgo v0.0.0-20180226025133-644b8db467af h1:wVe6/Ea46ZMeNkQjjBW6xcqyQA/j5e0D6GytH95g0gQ=
@@ -18,6 +19,7 @@ github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs
 github.com/fogleman/gg v1.2.1-0.20190220221249-0403632d5b90/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k=
 github.com/fogleman/gg v1.3.0 h1:/7zJX8F6AaYQc57WQCyN9cAIz+4bCJGO9B+dyW29am8=
 github.com/fogleman/gg v1.3.0/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k=
+github.com/go-gl/glfw/v3.3/glfw v0.0.0-20191125211704-12ad95a8df72/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
 github.com/gogo/protobuf v1.3.0 h1:G8O7TerXerS4F6sx9OV7/nRfJdnXgHZu/S/7F2SN+UE=
 github.com/gogo/protobuf v1.3.0/go.mod h1:SlYgWuQ5SjCEi6WLHjHCa1yvBfUnHcTbrrZtXPKa29o=
 github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 h1:DACJavvAHhabrF08vX0COfcOBJRhZ8lUbR+ZWIs0Y5g=
@@ -41,6 +43,8 @@ github.com/pa-m/optimize v0.0.0-20190612075243-15ee852a6d9a h1:cgsB0XsJwsMq0JifJ
 github.com/pa-m/optimize v0.0.0-20190612075243-15ee852a6d9a/go.mod h1:gHioqOgOl5Wa4lmyUg/ojarU7Dfdkh/OnTnGA/WexsY=
 github.com/pa-m/randomkit v0.0.0-20190612075210-f24d270692b4 h1:+LyPTCDcQRARqza7LfS0w7v03e7VYceqQNTE8eRcGA4=
 github.com/pa-m/randomkit v0.0.0-20190612075210-f24d270692b4/go.mod h1:2Ix1Kyeujyr6FhU2SPX4iyiEpEBjHHcRV/Mki06ACcE=
+github.com/pa-m/randomkit v0.0.0-20191001073902-db4fd80633df h1:waQf2YvgkQdOEK4IvtzwNIuFAo2FZd34JtAb/wrLbbc=
+github.com/pa-m/randomkit v0.0.0-20191001073902-db4fd80633df/go.mod h1:rEyYBR/jbMkj6lX7VpWTAPPrjDIi/aNhAXmFuLMZS4o=
 github.com/phpdave11/gofpdi v1.0.7/go.mod h1:vBmVV0Do6hSBHC8uKUQ71JGW+ZGQq74llk/7bXwjDoI=
 github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
@@ -61,6 +65,7 @@ golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2 h1:VklqNMn3ovrHsnt90Pveol
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20190829043050-9756ffdc2472/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/exp v0.0.0-20180321215751-8460e604b9de h1:xSjD6HQTqT0H/k60N5yYBtnN1OEkVy7WIo/DYyxKRO0=
 golang.org/x/exp v0.0.0-20180321215751-8460e604b9de/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20180807140117-3d87b88a115f h1:9kQ594xxPWRNKfTOnPjPcgrIJ19zM3ic57aI7PbMyAA=
@@ -71,8 +76,11 @@ golang.org/x/exp v0.0.0-20190312203227-4b39c73a6495 h1:I6A9Ag9FpEKOjcKrRNjQkPHaw
 golang.org/x/exp v0.0.0-20190312203227-4b39c73a6495/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
 golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522 h1:OeRHuibLsmZkFj773W4LcfAGsSxJgfPONhr8cmO+eLA=
 golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
+golang.org/x/exp v0.0.0-20190731235908-ec7cb31e5a56/go.mod h1:JhuoJpWY28nO4Vef9tZUw9qufEGTyX1+7lmHxV5q5G4=
 golang.org/x/exp v0.0.0-20190829153037-c13cbed26979 h1:Agxu5KLo8o7Bb634SVDnhIfpTvxmzUwhbYAzBvXt6h4=
 golang.org/x/exp v0.0.0-20190829153037-c13cbed26979/go.mod h1:86+5VVa7VpoJ4kLfm080zCjGlMRFzhUhsZKEZO7MGek=
+golang.org/x/exp v0.0.0-20191129062945-2f5052295587 h1:5Uz0rkjCFu9BC9gCRN7EkwVvhNyQgGWb8KNJrPwBoHY=
+golang.org/x/exp v0.0.0-20191129062945-2f5052295587/go.mod h1:2RIsYlXP63K8oxa1u096TMicItID8zy7Y6sNkU49FU4=
 golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81 h1:00VmoueYNlNz/aHIilyyQz/MHSqGoWJzpFv/HW8xpzI=
 golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81/go.mod h1:ux5Hcp/YLpHSI86hEcLt0YII63i6oz57MZXIpbrjZUs=
 golang.org/x/image v0.0.0-20190227222117-0694c2d4d067 h1:KYGJGHOQy8oSi1fDlSpcZF0+juKwk/hEMv5SiwHogR0=
@@ -87,17 +95,20 @@ golang.org/x/image v0.0.0-20190902063713-cb417be4ba39/go.mod h1:FeLwcggjj3mMvU+o
 golang.org/x/mobile v0.0.0-20190312151609-d3739f865fa6/go.mod h1:z+o9i4GpDbdi3rU15maQ/Ox0txvL9dWGYEHz965HBQE=
 golang.org/x/mobile v0.0.0-20190607214518-6fa95d984e88/go.mod h1:E/iHnbuqvinMTCcRqshq8CkpyQDoeVncDDYHnLhea+o=
 golang.org/x/mobile v0.0.0-20190719004257-d2bd2a29d028/go.mod h1:E/iHnbuqvinMTCcRqshq8CkpyQDoeVncDDYHnLhea+o=
+golang.org/x/mobile v0.0.0-20190830201351-c6da95954960/go.mod h1:mJOp/i0LXPxJZ9weeIadcPqKVfS05Ai7m6/t9z1Hs/Y=
 golang.org/x/mod v0.1.0/go.mod h1:0QHyrYULN0/3qlju5TqG8bIK38QM8yzMo5ekMj3DlcY=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190611141213-3f473d35a33a/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20190827160401-ba9fcec4b297/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190312061237-fead79001313 h1:pczuHS43Cp2ktBEEmLwScxgjWsBSzdaQiKzUyf3DTTc=
 golang.org/x/sys v0.0.0-20190312061237-fead79001313/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190610200419-93c9922d18ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190904154756-749cb33beabd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
@@ -112,6 +123,8 @@ golang.org/x/tools v0.0.0-20190611222205-d73e1c7e250b/go.mod h1:/rFqwRUd4F7ZHNgw
 golang.org/x/tools v0.0.0-20190816200558-6889da9d5479/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20190905235650-93dcc2f048f5 h1:xU4gBaA7ny56EkBSp9Uw2MVovJDupIfONnEOZ+FChTY=
 golang.org/x/tools v0.0.0-20190905235650-93dcc2f048f5/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20191012152004-8de300cfc20a h1:TwMENskLwU2NnWBzrJGEWHqSiGUkO/B4rfyhwqDxDYQ=
+golang.org/x/tools v0.0.0-20191012152004-8de300cfc20a/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gonum.org/v1/gonum v0.0.0-20180816165407-929014505bf4/go.mod h1:Y+Yx5eoAFn32cQvJDxZx5Dpnq+c3wtXuadVZAcxbbBo=
 gonum.org/v1/gonum v0.0.0-20190331200053-3d26580ed485 h1:OB/uP/Puiu5vS5QMRPrXCDWUPb+kt8f1KW8oQzFejQw=

linear_model/logistic.go

@@ -170,7 +170,7 @@ func NewLogisticRegression() *LogisticRegression {
 func (m *LogisticRegression) PredicterClone() base.Predicter {
 	clone := *m
 	if sc, ok := m.RandomState.(base.SourceCloner); ok {
-		clone.RandomState = sc.Clone()
+		clone.RandomState = sc.SourceClone()
 	}
 	return &clone
 }

model_selection/search.go

@@ -70,7 +70,7 @@ func (gscv *GridSearchCV) PredicterClone() base.Predicter {
 	}
 	clone := *gscv
 	if sourceCloner, ok := clone.RandomState.(base.SourceCloner); ok && sourceCloner != base.SourceCloner(nil) {
-		clone.RandomState = sourceCloner.Clone()
+		clone.RandomState = sourceCloner.SourceClone()
 	}
 	return &clone
 }

model_selection/search_test.go

@@ -88,8 +88,9 @@ func chkRandomState(rs rand.Source) {
 		panic(fmt.Errorf("wrong random state\nexpected:%s\n%s\ngot     :%s\n%s", expected, "", got, ""))
 	}
 }
+
 func ExampleGridSearchCV() {
-	RandomState := base.NewSource(7)
+	RandomState := base.NewLockedSource(7)
 	ds := datasets.LoadBoston()
 	X, Y := preprocessing.NewStandardScaler().FitTransform(ds.X, ds.Y)
 
@@ -99,14 +100,15 @@ func ExampleGridSearchCV() {
 	mlp.BatchSize = 20
 	mlp.LearningRateInit = .005
 	mlp.MaxIter = 100
+
 	scorer := func(Y, Ypred mat.Matrix) float64 {
 		return metrics.MeanSquaredError(Y, Ypred, nil, "").At(0, 0)
 	}
 	gscv := &GridSearchCV{
 		Estimator: mlp,
 		ParamGrid: map[string][]interface{}{
-			"Alpha":       {2e-4, 5e-4, 1e-3},
-			"WeightDecay": {.0002, .0001, 0},
+			"Alpha":       {1e-4, 2e-4, 5e-4, 1e-3},
+			"WeightDecay": {1e-4, 1e-5, 1e-6,1e-7,1e-8, 0},
 		},
 		Scorer:             scorer,
 		LowerScoreIsBetter: true,
@@ -120,7 +122,7 @@ func ExampleGridSearchCV() {
 
 	// Output:
 	// Alpha 0.0002
-	// WeightDecay 0
+	// WeightDecay 1e-06
 
 }
 

model_selection/split.go

@@ -1,12 +1,10 @@
 package modelselection
 
 import (
-	"github.com/pa-m/sklearn/base"
 	"math"
-	"sort"
 
+	"github.com/pa-m/sklearn/base"
 	"golang.org/x/exp/rand"
-
 	"gonum.org/v1/gonum/mat"
 )
 
@@ -41,7 +39,7 @@ func (splitter *KFold) SplitterClone() Splitter {
 	}
 	clone := *splitter
 	if sourceCloner, ok := clone.RandomState.(base.SourceCloner); ok && sourceCloner != base.SourceCloner(nil) {
-		clone.RandomState = sourceCloner.Clone()
+		clone.RandomState = sourceCloner.SourceClone()
 	}
 	return &clone
 }
@@ -114,29 +112,33 @@ func (splitter *KFold) GetNSplits(X, Y *mat.Dense) int {
 
 // TrainTestSplit splits X and Y into test set and train set
 // testsize must be between 0 and 1
-// it does'nt yet produce same sets than scikit-learn du to a different shuffle method
+// it produce same sets than scikit-learn
 func TrainTestSplit(X, Y mat.Matrix, testsize float64, randomstate uint64) (Xtrain, Xtest, ytrain, ytest *mat.Dense) {
 	NSamples, NFeatures := X.Dims()
 	_, NOutputs := Y.Dims()
 	var testlen int
 	if testsize > 1 {
-		testlen = int(math.Round(math.Min(float64(NSamples), testsize)))
+		testlen = int(math.Ceil(math.Min(float64(NSamples), testsize)))
 	} else {
-		testlen = int(math.Round(float64(NSamples) * testsize))
+		testlen = int(math.Ceil(float64(NSamples) * testsize))
 	}
 	Xtest = mat.NewDense(testlen, NFeatures, nil)
 	ytest = mat.NewDense(testlen, NOutputs, nil)
 	Xtrain = mat.NewDense(NSamples-testlen, NFeatures, nil)
 	ytrain = mat.NewDense(NSamples-testlen, NOutputs, nil)
 	src := base.NewLockedSource(randomstate)
-	shuffler := rand.New(src)
-	ind := make([]int, NSamples)
-	for i := range ind {
-		ind[i] = i
-	}
-	//shuffle ind
-	slice := sort.IntSlice(ind)
-	shuffler.Shuffle(slice.Len(), slice.Swap)
+
+	var ind []int
+	src.WithLock(func(src base.Source) {
+		permer, ok := src.(base.Permer)
+		if !ok {
+			panic("Source does not implement Perm")
+		}
+		{
+			ind = permer.Perm(NSamples)
+		}
+
+	})
 	for i := 0; i < NSamples; i++ {
 		j := ind[i]
 		if i < testlen {

model_selection/split_test.go

@@ -2,8 +2,8 @@ package modelselection
 
 import (
 	"fmt"
-	"github.com/pa-m/randomkit"
-	"testing"
+
+	"github.com/pa-m/sklearn/datasets"
 
 	"github.com/pa-m/sklearn/base"
 	"golang.org/x/exp/rand"
@@ -50,15 +50,70 @@ func perm(r base.Intner, n int) []int {
 	return m
 
 }
-func TestTrainTestSplit(t *testing.T) {
-	rs := randomkit.NewRandomkitSource(42)
-	NSamples := 178
-	ind := make([]int, NSamples)
-	for i := range ind {
-		ind[i] = i
-	}
-	permer := rand.New(rs)
-	ind = permer.Perm(178)
-	fmt.Println(ind)
+
+func _ExampleTrainTestSplit() {
+
+	features, target := datasets.LoadWine().GetXY()
+	RandomState := uint64(42)
+	_, _, Ytrain, Ytest := TrainTestSplit(features, target, .30, RandomState)
+	Ntrain, _ := Ytrain.Dims()
+	ytrain := make([]float64, Ntrain)
+	mat.Col(ytrain, 0, Ytrain)
+	fmt.Println(ytrain[:8])
+	Ntest, _ := Ytest.Dims()
+	ytest := make([]float64, Ntest)
+	mat.Col(ytest, 0, Ytest)
+	fmt.Println(ytest[:8])
+
 	// Output:
+	//[2 1 1 0 1 0 2 1]
+	//[0 0 2 0 1 0 1 2]
+}
+
+func ExampleTrainTestSplit() {
+	/*
+	   >>> import numpy as np
+	   >>> from sklearn.model_selection import train_test_split
+	   >>> X, y = np.arange(10).reshape((5, 2)), range(5)
+	   >>> X_train, X_test, y_train, y_test = train_test_split(
+	   ...     X, y, test_size=0.33, random_state=42)
+	   ...
+	   >>> X_train
+	   array([[4, 5],
+	          [0, 1],
+	          [6, 7]])
+	   >>> y_train
+	   [2, 0, 3]
+	   >>> X_test
+	   array([[2, 3],
+	          [8, 9]])
+	   >>> y_test
+	   [1, 4]
+
+	*/
+	X := mat.NewDense(5, 2, []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9})
+	Y := mat.NewDense(5, 1, []float64{0, 1, 2, 3, 4})
+	RandomState := uint64(42)
+	Xtrain, Xtest, Ytrain, Ytest := TrainTestSplit(X, Y, .33, RandomState)
+	fmt.Printf("X_train:\n%g\n", mat.Formatted(Xtrain))
+	fmt.Printf("Y_train:\n%g\n", mat.Formatted(Ytrain))
+	fmt.Printf("X_test:\n%g\n", mat.Formatted(Xtest))
+	fmt.Printf("Y_test:\n%g\n", mat.Formatted(Ytest))
+
+	// Output:
+	//X_train:
+	//⎡4  5⎤
+	//⎢0  1⎥
+	//⎣6  7⎦
+	//Y_train:
+	//⎡2⎤
+	//⎢0⎥
+	//⎣3⎦
+	//X_test:
+	//⎡2  3⎤
+	//⎣8  9⎦
+	//Y_test:
+	//⎡1⎤
+	//⎣4⎦
+
 }