Fix#111 (#112)

* Fixed #90

* Fixed #111

* Boyscout commit to fix python/numpy testing

defaultengine_mapreduce.go

@@ -178,15 +178,27 @@ func (e StdEng) OptimizedReduce(a Tensor, axis int, firstFn, lastFn, defaultFn,
 }
 
 func (e StdEng) Sum(a Tensor, along ...int) (retVal Tensor, err error) {
-	return e.reduce("Sum", execution.MonotonicSum, execution.SumMethods, a, along...)
+	a2 := a
+	if v, ok := a.(View); ok && v.IsMaterializable() {
+		a2 = v.Materialize()
+	}
+	return e.reduce("Sum", execution.MonotonicSum, execution.SumMethods, a2, along...)
 }
 
 func (e StdEng) Min(a Tensor, along ...int) (retVal Tensor, err error) {
-	return e.reduce("Min", execution.MonotonicMin, execution.MinMethods, a, along...)
+	a2 := a
+	if v, ok := a.(View); ok && v.IsMaterializable() {
+		a2 = v.Materialize()
+	}
+	return e.reduce("Min", execution.MonotonicMin, execution.MinMethods, a2, along...)
 }
 
 func (e StdEng) Max(a Tensor, along ...int) (retVal Tensor, err error) {
-	return e.reduce("Max", execution.MonotonicMax, execution.MaxMethods, a, along...)
+	a2 := a
+	if v, ok := a.(View); ok && v.IsMaterializable() {
+		a2 = v.Materialize()
+	}
+	return e.reduce("Max", execution.MonotonicMax, execution.MaxMethods, a2, along...)
 }
 
 func (e StdEng) reduce(

dense_io_test.go

@@ -3,6 +3,7 @@ package tensor
 import (
 	"bytes"
 	"encoding/gob"
+	"io/ioutil"
 	"os"
 	"os/exec"
 	"regexp"
@@ -30,6 +31,19 @@ func TestSaveLoadNumpy(t *testing.T) {
 	T1D.WriteNpy(f1D)
 	f1D.Close()
 
+	defer func() {
+		// cleanup
+		err := os.Remove("test.npy")
+		if err != nil {
+			t.Error(err)
+		}
+
+		err = os.Remove("test1D.npy")
+		if err != nil {
+			t.Error(err)
+		}
+	}()
+
 	script := "import numpy as np\nx = np.load('test.npy')\nprint(x)\nx = np.load('test1D.npy')\nprint(x)"
 	// Configurable python command, in order to be able to use python or python3
 	pythonCommand := os.Getenv("PYTHON_COMMAND")
@@ -42,6 +56,10 @@ func TestSaveLoadNumpy(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
+	stderr, err := cmd.StderrPipe()
+	if err != nil {
+		t.Error(err)
+	}
 
 	go func() {
 		defer stdin.Close()
@@ -56,29 +74,21 @@ func TestSaveLoadNumpy(t *testing.T) {
 		t.Logf("Do you have a python with numpy installed? You can change the python interpreter by setting the environment variable PYTHON_COMMAND. Current value: PYTHON_COMMAND=%s", pythonCommand)
 	}
 
+	importError := `ImportError: No module named numpy`
+	slurpErr, _ := ioutil.ReadAll(stderr)
+	if ok, _ := regexp.Match(importError, slurpErr); ok {
+		t.Skipf("Skipping numpy test. It would appear that you do not have Numpy installed.")
+	}
+
 	if err := cmd.Wait(); err != nil {
-		t.Error(err)
+		t.Errorf("%q", err.Error())
 	}
 
 	expected := `\[\[\s*1\.\s*5\.\]\n \[\s*10\.\s*-1\.\]\]\n`
 	if ok, _ := regexp.Match(expected, buf.Bytes()); !ok {
 		t.Errorf("Did not successfully read numpy file, \n%q\n%q", buf.String(), expected)
 	}
 
-	if buf.String() != expected {
-	}
-
-	// cleanup
-	err = os.Remove("test.npy")
-	if err != nil {
-		t.Error(err)
-	}
-
-	err = os.Remove("test1D.npy")
-	if err != nil {
-		t.Error(err)
-	}
-
 	// ok now to test if it can read
 	T2 := new(Dense)
 	buf = new(bytes.Buffer)

example_dense_matop_test.go

@@ -85,6 +85,68 @@ func ExampleDense_Slice_viewMutation() {
 	//
 }
 
+func ExampleView() {
+	// Slicing creates a "view" on the original tensor
+	T := New(WithBacking(Range(Int, 0, 16)), WithShape(4, 4))
+	fmt.Printf("T:\n%v\n", T)
+	V, _ := T.Slice(makeRS(1, 3), makeRS(1, 3))
+	fmt.Printf("V:\n%v\n", V)
+
+	// Now we modify V's 0th value
+	V.(*Dense).Set(0, 1000)
+	fmt.Printf("V[0] = 1000:\n%v\n", V)
+	fmt.Printf("T is also mutated:\n%v\n", T)
+
+	// Now we materialize the views
+	fmt.Printf("V is Materializable: %v\n", V.IsMaterializable())
+	T2 := V.Materialize()
+	fmt.Printf("T2 == V:\n%v\n", T2)
+
+	// Once materialized, it is decoupled from the original tensor
+	T2.(*Dense).Set(0, 999)
+	fmt.Printf("T2 is mutated:\n%v\nBut T is not mutated:\n%v\nNeither is V:\n%v", T2, T, V)
+	// Output:
+	// T:
+	// ⎡ 0   1   2   3⎤
+	// ⎢ 4   5   6   7⎥
+	// ⎢ 8   9  10  11⎥
+	// ⎣12  13  14  15⎦
+	//
+	// V:
+	// ⎡ 5   6⎤
+	// ⎣ 9  10⎦
+	//
+	// V[0] = 1000:
+	// ⎡1000     6⎤
+	// ⎣   9    10⎦
+	//
+	// T is also mutated:
+	// ⎡   0     1     2     3⎤
+	// ⎢   4  1000     6     7⎥
+	// ⎢   8     9    10    11⎥
+	// ⎣  12    13    14    15⎦
+	//
+	// V is Materializable: true
+	// T2 == V:
+	// ⎡1000     6⎤
+	// ⎣   9    10⎦
+	//
+	// T2 is mutated:
+	// ⎡999    6⎤
+	// ⎣  9   10⎦
+	//
+	// But T is not mutated:
+	// ⎡   0     1     2     3⎤
+	// ⎢   4  1000     6     7⎥
+	// ⎢   8     9    10    11⎥
+	// ⎣  12    13    14    15⎦
+	//
+	// Neither is V:
+	// ⎡1000     6⎤
+	// ⎣   9    10⎦
+
+}
+
 func ExampleDense_Hstack() {
 	var T, T1, T2, T3 *Dense
 	var err error

example_mapreduce_test.go

@@ -31,6 +31,27 @@ func ExampleSum() {
 	// Summed along (1, 0): 6
 }
 
+func ExampleSum_sliced() {
+	T := New(WithBacking([]float64{0, 1, 2, 3}), WithShape(2, 2))
+	fmt.Printf("T:\n%v\n", T)
+
+	V, _ := T.Slice(nil, sli(1))
+	fmt.Printf("V:\n%v\n", V)
+
+	Σ, _ := Sum(V)
+	fmt.Printf("Σ: %v", Σ)
+
+	// Output:
+	// T:
+	// ⎡0  1⎤
+	// ⎣2  3⎦
+	//
+	// V:
+	// [1  3]
+	// Σ: 4
+
+}
+
 func ExampleArgmax() {
 	T := New(WithBacking([]float64{0, 100, 200, 3}), WithShape(2, 2))
 	fmt.Printf("T:\n%v\n", T)
@@ -49,6 +70,28 @@ func ExampleArgmax() {
 	// Argmax is *tensor.Dense of int
 }
 
+func ExampleArgmax_sliced() {
+	T := New(WithBacking([]float64{0, 100, 200, 3}), WithShape(2, 2))
+	fmt.Printf("T:\n%v\n", T)
+
+	// slice  creates a view
+	V, _ := T.Slice(nil, sli(1))
+
+	// argmax along the x-axis
+	am, _ := Argmax(V, 0)
+	fmt.Printf("Argmax: %v\n", am)
+	fmt.Printf("Argmax is %T of %v", am, am.Dtype())
+
+	// Output:
+	// T:
+	// ⎡  0  100⎤
+	// ⎣200    3⎦
+	//
+	// Argmax: 0
+	// Argmax is *tensor.Dense of int
+
+}
+
 func ExampleArgmin() {
 	T := New(WithBacking([]float64{0, 100, 200, 3}), WithShape(2, 2))
 	fmt.Printf("T:\n%v\n", T)