Added Identity operator

ops/identity/identity.go

@@ -0,0 +1,42 @@
+package identity
+
+import (
+	"github.com/advancedclimatesystems/gonnx/onnx"
+	"github.com/advancedclimatesystems/gonnx/ops"
+	"gorgonia.org/tensor"
+)
+
+var identityTypeConstraints = [][]tensor.Dtype{ops.AllTypes}
+
+// Identity represents the ONNX identity operator.
+type Identity struct {
+	ops.BaseOperator
+}
+
+// newIdentity creates a new identity operator.
+func newIdentity(version int, typeConstraints [][]tensor.Dtype) ops.Operator {
+	return &Identity{
+		BaseOperator: ops.NewBaseOperator(
+			version,
+			1,
+			1,
+			typeConstraints,
+			"identity",
+		),
+	}
+}
+
+// Init initializes the identity operator.
+func (a *Identity) Init(*onnx.NodeProto) error {
+	return nil
+}
+
+// Apply applies the identity operator.
+func (a *Identity) Apply(inputs []tensor.Tensor) ([]tensor.Tensor, error) {
+	out, ok := inputs[0].Clone().(tensor.Tensor)
+	if !ok {
+		return nil, ops.ErrTypeAssert("tensor.Tensor", inputs[0].Clone())
+	}
+
+	return []tensor.Tensor{out}, nil
+}

ops/identity/identity_test.go

@@ -0,0 +1,100 @@
+package identity
+
+import (
+	"testing"
+
+	"github.com/advancedclimatesystems/gonnx/ops"
+	"github.com/stretchr/testify/assert"
+	"gorgonia.org/tensor"
+)
+
+func TestIdentityInit(t *testing.T) {
+	i := &Identity{}
+
+	// since 'identity' does not have any attributes we pass in nil. This should not
+	// fail initializing the identity.
+	err := i.Init(nil)
+	assert.Nil(t, err)
+}
+
+func TestIdentity(t *testing.T) {
+	tests := []struct {
+		version  int64
+		backing  []float32
+		shape    []int
+		expected []float32
+	}{
+		{
+			13,
+			[]float32{0, 1, 2, 3},
+			[]int{2, 2},
+			[]float32{0, 1, 2, 3},
+		},
+	}
+
+	for _, test := range tests {
+		inputs := []tensor.Tensor{
+			ops.TensorWithBackingFixture(test.backing, test.shape...),
+		}
+
+		identity := identityVersions[test.version]()
+
+		res, err := identity.Apply(inputs)
+		assert.Nil(t, err)
+
+		assert.Equal(t, test.expected, res[0].Data())
+	}
+}
+
+func TestInputValidationIdentity(t *testing.T) {
+	tests := []struct {
+		version int64
+		inputs  []tensor.Tensor
+		err     error
+	}{
+		{
+			13,
+			[]tensor.Tensor{
+				ops.TensorWithBackingFixture([]uint32{1, 2}, 2),
+			},
+			nil,
+		},
+		{
+			13,
+			[]tensor.Tensor{
+				ops.TensorWithBackingFixture([]float32{1, 2}, 2),
+			},
+			nil,
+		},
+		{
+			13,
+			[]tensor.Tensor{
+				ops.TensorWithBackingFixture([]float32{1, 2}, 2),
+				ops.TensorWithBackingFixture([]float32{3, 4}, 2),
+			},
+			ops.ErrInvalidInputCount(2, identity13BaseOpFixture()),
+		},
+		{
+			13,
+			[]tensor.Tensor{
+				ops.TensorWithBackingFixture([]int{1, 2}, 2),
+			},
+			ops.ErrInvalidInputType(0, "int", identity13BaseOpFixture()),
+		},
+	}
+
+	for _, test := range tests {
+		identity := identityVersions[test.version]()
+		validated, err := identity.ValidateInputs(test.inputs)
+
+		assert.Equal(t, test.err, err)
+
+		if test.err == nil {
+			assert.Equal(t, test.inputs, validated)
+		}
+	}
+}
+
+func identity13BaseOpFixture() ops.BaseOperator {
+	return ops.NewBaseOperator(13, 1, 1, identityTypeConstraints, "identity")
+}

ops/identity/versions.go

@@ -0,0 +1,13 @@
+package identity
+
+import (
+	"github.com/advancedclimatesystems/gonnx/ops"
+)
+
+var identityVersions = ops.OperatorVersions{
+	13: ops.NewOperatorConstructor(newIdentity, 13, identityTypeConstraints),
+}
+
+func GetVersions() ops.OperatorVersions {
+	return identityVersions
+}

ops_test.go

@@ -82,6 +82,8 @@ var ignoredTests = []string{
 	"test_softmax_axis_2_expanded_ver18",              // Opset18
 	"test_reshape_allowzero_reordered",                // Opset14
 
+	"test_identity_opt", // Error in test? Can not read in input tensor. https://github.com/onnx/onnx/issues/6842
+
 	"test_constant_pad",                      // Pad is not implemented yet.
 	"test_constant_pad_axes",                 // Pad is not implemented yet.
 	"test_logsoftmax_large_number_expanded",  // Requires 'Exp' operator.
@@ -458,6 +460,8 @@ var expectedTests = []string{
 	"test_gru_defaults",
 	"test_gru_seq_length",
 	"test_gru_with_initial_bias",
+	"test_identity",
+	"test_identity_sequence",
 	"test_less",
 	"test_less_bcast",
 	"test_less_equal",

opset.go

@@ -30,6 +30,7 @@ import (
 	"github.com/advancedclimatesystems/gonnx/ops/greater"
 	"github.com/advancedclimatesystems/gonnx/ops/greaterorequal"
 	"github.com/advancedclimatesystems/gonnx/ops/gru"
+	"github.com/advancedclimatesystems/gonnx/ops/identity"
 	"github.com/advancedclimatesystems/gonnx/ops/less"
 	"github.com/advancedclimatesystems/gonnx/ops/lessorequal"
 	"github.com/advancedclimatesystems/gonnx/ops/linearregressor"
@@ -102,6 +103,7 @@ var operators = map[string]ops.OperatorVersions{
 	"Greater":         greater.GetVersions(),
 	"GreaterOrEqual":  greaterorequal.GetVersions(),
 	"GRU":             gru.GetVersions(),
+	"Identity":        identity.GetVersions(),
 	"Less":            less.GetVersions(),
 	"LessOrEqual":     lessorequal.GetVersions(),
 	"LinearRegressor": linearregressor.GetVersions(),
@@ -134,7 +136,7 @@ var operators = map[string]ops.OperatorVersions{
 	"Transpose":       transpose.GetVersions(),
 	"Unsqueeze":       unsqueeze.GetVersions(),
 	"Xor":             xor.GetVersions(),
-        "Where": where.GetVersions(),
+	"Where":           where.GetVersions(),
 }
 
 // GetClosestOperatorVersion resolves, given a certain opset version, the operator version that is closest