go: Add an example.

Add an example (that will appear in Go doc) for a real use of the Go TensorFlow
APIs - using a pre-defined image recognition model for inference.

While at it a couple of minor tweaks:
- NewSession now accepts 'nil' for options as the documentation says it does
- Convenience accessors for the Outputs of an Operation
- Ability to extract (possibly partial) shapes from an Output

Another step towards #10
Change: 134560938

1 files changed, 63 insertions, 0 deletions

diff --git a/tensorflow/go/operation_test.go b/tensorflow/go/operation_test.go
index 7cba0a5c27..35a5d95357 100644
--- a/tensorflow/go/operation_test.go
+++ b/tensorflow/go/operation_test.go
@@ -15,6 +15,7 @@
 package tensorflow
 
 import (
+	"fmt"
 	"runtime"
 	"runtime/debug"
 	"testing"
@@ -50,6 +51,68 @@ func TestOperationLifetime(t *testing.T) {
 	}
 }
 
+func TestOutputShape(t *testing.T) {
+	graph := NewGraph()
+	testdata := []struct {
+		Value interface{}
+		Shape []int64
+	}{
+		{ // Scalar
+			int64(0),
+			[]int64{},
+		},
+		{ // Vector
+			[]int64{1, 2, 3},
+			[]int64{3},
+		},
+		{ // Matrix
+			[][]float64{
+				{1, 2, 3},
+				{4, 5, 6},
+			},
+			[]int64{2, 3},
+		},
+	}
+	for idx, test := range testdata {
+		tensor, err := NewTensor(test.Value)
+		if err != nil {
+			t.Errorf("#%d: NewTensor(%T) failed: %v", idx, test.Value, err)
+			continue
+		}
+		c, err := Const(graph, fmt.Sprintf("test%d", idx), tensor)
+		if err != nil {
+			t.Errorf("#%d: Const(%T) failed: %v", idx, test.Value, err)
+			continue
+		}
+		shape, err := c.Shape()
+		if err != nil {
+			t.Errorf("#%d: Shape() failed for %T: %v", idx, test.Value, err)
+			continue
+		}
+		if got, want := len(shape), len(test.Shape); got != want {
+			t.Errorf("#%d: %T: Got a shape with %d dimensions, want %d", idx, test.Value, got, want)
+			continue
+		}
+		for i := 0; i < len(shape); i++ {
+			if got, want := shape[i], test.Shape[i]; got != want {
+				t.Errorf("#%d: %T: Got %d, want %d for dimension #%d/%d", idx, test.Value, got, want, i, len(shape))
+			}
+		}
+	}
+	// Unknown number of dimensions
+	dummyTensor, err := NewTensor(float64(0))
+	if err != nil {
+		t.Fatal(err)
+	}
+	placeholder, err := Placeholder(graph, "placeholder", dummyTensor.DataType())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if shape, err := placeholder.Shape(); err == nil {
+		t.Errorf("Got shape %v, wanted error", shape)
+	}
+}
+
 func forceGC() {
 	var mem runtime.MemStats
 	runtime.ReadMemStats(&mem)