Allowing tf.lookup tables to be initialized from a Dataset

PiperOrigin-RevId: 298464567
Change-Id: I8f5bbc175af1f8a6c19b0febb81ba30e6fd73b47

tensorflow/core/api_def/base_api/api_def_InitializeTableFromDataset.pbtxt

@@ -0,0 +1,4 @@
+op {
+  graph_op_name: "InitializeTableFromDataset"
+  visibility: HIDDEN
+}

tensorflow/core/kernels/lookup_table_init_op.cc

@@ -21,6 +21,7 @@ limitations under the License.
 #include <string>
 #include <vector>
 
+#include "tensorflow/core/framework/dataset.h"
 #include "tensorflow/core/framework/op_kernel.h"
 #include "tensorflow/core/framework/register_types.h"
 #include "tensorflow/core/framework/tensor.h"
@@ -163,4 +164,26 @@ REGISTER_KERNEL_BUILDER(
     Name("InitializeTableFromTextFileV2").Device(DEVICE_CPU),
     InitializeTableFromTextFileOp);
 
+class InitializeTableFromDatasetOp : public OpKernel {
+ public:
+  explicit InitializeTableFromDatasetOp(OpKernelConstruction* ctx)
+      : OpKernel(ctx) {}
+
+  void Compute(OpKernelContext* ctx) override {
+    lookup::InitializableLookupTable* table;
+    OP_REQUIRES_OK(ctx,
+                   GetInitializableLookupTable("table_handle", ctx, &table));
+    core::ScopedUnref unref_me(table);
+    DatasetBase* dataset;
+    OP_REQUIRES_OK(ctx, GetDatasetFromVariantTensor(ctx->input(1), &dataset));
+    OP_REQUIRES_OK(ctx,
+                   lookup::InitializeTableFromDataset(ctx, dataset, table));
+  }
+
+ private:
+  TF_DISALLOW_COPY_AND_ASSIGN(InitializeTableFromDatasetOp);
+};
+
+REGISTER_KERNEL_BUILDER(Name("InitializeTableFromDataset").Device(DEVICE_CPU),
+                        InitializeTableFromDatasetOp);
 }  // namespace tensorflow

tensorflow/core/kernels/lookup_table_op.h

@@ -221,7 +221,9 @@ class HashTable : public InitializableLookupTable {
     if (is_initialized()) {
       return errors::Aborted("HashTable already initialized.");
     }
-    table_.reserve(size);
+    if (size > 0) {
+      table_.reserve(size);
+    }
     return Status::OK();
   };
 

tensorflow/core/kernels/lookup_util.cc

@@ -15,6 +15,8 @@ limitations under the License.
 
 #include "tensorflow/core/kernels/lookup_util.h"
 
+#include "tensorflow/core/framework/dataset.h"
+#include "tensorflow/core/framework/function_handle_cache.h"
 #include "tensorflow/core/framework/tensor.h"
 #include "tensorflow/core/framework/tensor_shape.h"
 #include "tensorflow/core/lib/core/errors.h"
@@ -390,5 +392,105 @@ Status InitializeTableFromTextFile(const string& filename, int64 vocab_size,
   return s;
 }
 
+class DatasetIterator : public InitializableLookupTable::InitTableIterator {
+ public:
+  explicit DatasetIterator(DatasetBase* dataset) : dataset_(dataset) {}
+
+  ~DatasetIterator() override {}
+
+  Status Init(OpKernelContext* ctx) {
+    IteratorContext::Params params(ctx);
+    function_handle_cache_ =
+        absl::make_unique<data::FunctionHandleCache>(params.flr);
+    params.function_handle_cache = function_handle_cache_.get();
+    params.resource_mgr = &resource_mgr_;
+    cancellation_manager_ =
+        absl::make_unique<CancellationManager>(ctx->cancellation_manager());
+    params.cancellation_manager = cancellation_manager_.get();
+    iterator_ctx_ = absl::make_unique<IteratorContext>(std::move(params));
+    TF_RETURN_IF_ERROR(dataset_->MakeIterator(iterator_ctx_.get(), nullptr,
+                                              "LookupTable", &iterator_));
+    Next();
+    return Status::OK();
+  }
+
+  void Next() override {
+    bool end_of_input;
+    tensors_.clear();
+    status_ = iterator_->GetNext(iterator_ctx_.get(), &tensors_, &end_of_input);
+    if (status_.ok() && end_of_input) {
+      status_ = errors::OutOfRange("end of iterator");
+    }
+  }
+
+  bool Valid() const override { return status_.ok(); }
+
+  const Tensor& keys() const override { return tensors_[0]; }
+
+  const Tensor& values() const override { return tensors_[1]; }
+
+  Status status() const override { return status_; }
+
+  int64 total_size() const override {
+    int64 size = dataset_->Cardinality();
+    if (size < 0) {
+      return 0;
+    }
+    return size;
+  }
+
+ private:
+  DatasetBase* dataset_;  // not owned.
+  std::unique_ptr<IteratorContext> iterator_ctx_;
+  std::unique_ptr<data::FunctionHandleCache> function_handle_cache_;
+  ResourceMgr resource_mgr_;
+  std::unique_ptr<CancellationManager> cancellation_manager_;
+  std::unique_ptr<IteratorBase> iterator_;
+  std::vector<Tensor> tensors_;
+  Status status_;
+};
+
+Status InitializeTableFromDataset(OpKernelContext* ctx,
+                                  data::DatasetBase* dataset,
+                                  InitializableLookupTable* table) {
+  // Assert that the dataset types match up to that expected in the table.
+  const auto& dataset_types = dataset->output_dtypes();
+  if (dataset_types.size() != 2) {
+    return errors::InvalidArgument("Dataset should have two output types only");
+  }
+  if (dataset_types[0] != table->key_dtype()) {
+    return errors::InvalidArgument("Key dtype expected: ", table->key_dtype(),
+                                   " but obtained: ", dataset_types[0],
+                                   " from the dataset");
+  }
+  if (dataset_types[1] != table->value_dtype()) {
+    return errors::InvalidArgument(
+        "Value dtype expected: ", table->value_dtype(),
+        " but obtained: ", dataset_types[1], " from the dataset");
+  }
+  // Assert that the dataset output shapes are scalars.
+  const auto& dataset_shapes = dataset->output_shapes();
+  if (dataset_shapes.size() != 2) {
+    return errors::InvalidArgument(
+        "Dataset should have two output shapes only");
+  }
+  if (!dataset_shapes[0].IsCompatibleWith(PartialTensorShape({}))) {
+    return errors::InvalidArgument("Expected scalar for key. Obtained: ",
+                                   dataset_shapes[0].DebugString());
+  }
+  if (!dataset_shapes[1].IsCompatibleWith(PartialTensorShape({}))) {
+    return errors::InvalidArgument("Expected scalar for key. Obtained: ",
+                                   dataset_shapes[1].DebugString());
+  }
+  DatasetIterator iter(dataset);
+  TF_RETURN_IF_ERROR(iter.Init(ctx));
+  Status s = table->Initialize(iter);
+  if (errors::IsFailedPrecondition(s) && table->is_initialized()) {
+    LOG(INFO) << "Table already initialized from dataset.";
+    return Status::OK();
+  }
+  return s;
+}
+
 }  // namespace lookup
 }  // namespace tensorflow

tensorflow/core/kernels/lookup_util.h

@@ -20,6 +20,12 @@ limitations under the License.
 #include "tensorflow/core/framework/op_kernel.h"
 #include "tensorflow/core/kernels/initializable_lookup_table.h"
 
+namespace tensorflow {
+namespace data {
+class DatasetBase;
+}  // namespace data
+}  // namespace tensorflow
+
 namespace tensorflow {
 namespace lookup {
 
@@ -50,6 +56,12 @@ Status InitializeTableFromTextFile(const string& filename, int64 vocab_size,
                                    int32 value_index, Env* env,
                                    InitializableLookupTable* table);
 
+// Initializes `table` from `dataset` by iterating over it. Caller retains
+// ownership of `dataset`.
+Status InitializeTableFromDataset(OpKernelContext* ctx,
+                                  data::DatasetBase* dataset,
+                                  InitializableLookupTable* table);
+
 }  // namespace lookup
 }  // namespace tensorflow
 

tensorflow/core/ops/lookup_ops.cc

@@ -505,4 +505,14 @@ REGISTER_OP("InitializeTableFromTextFileV2")
       return Status::OK();
     });
 
+REGISTER_OP("InitializeTableFromDataset")
+    .Input("table_handle: resource")
+    .Input("dataset: variant")
+    .SetShapeFn([](InferenceContext* c) {
+      ShapeHandle handle;
+      TF_RETURN_IF_ERROR(c->WithRank(c->input(0), 0, &handle));
+      TF_RETURN_IF_ERROR(c->WithRank(c->input(1), 0, &handle));
+      return Status::OK();
+    });
+
 }  // namespace tensorflow

tensorflow/python/kernel_tests/BUILD

@@ -651,6 +651,8 @@ tf_py_test(
         "//tensorflow/python:lookup_ops",
         "//tensorflow/python:sparse_tensor",
         "//tensorflow/python:training",
+        "//tensorflow/python/data/ops:dataset_ops",
+        "//tensorflow/python/data/ops:readers",
     ],
 )
 

tensorflow/python/kernel_tests/lookup_ops_test.py

@@ -27,6 +27,7 @@ from tensorflow.python import tf2
 from tensorflow.python.client import session
 from tensorflow.python.data.experimental.ops import counter
 from tensorflow.python.data.ops import dataset_ops
+from tensorflow.python.data.ops import readers as reader_ops
 from tensorflow.python.eager import backprop
 from tensorflow.python.eager import context
 from tensorflow.python.eager import def_function
@@ -42,6 +43,7 @@ from tensorflow.python.ops import array_ops
 from tensorflow.python.ops import control_flow_ops
 from tensorflow.python.ops import lookup_ops
 from tensorflow.python.ops import map_fn
+from tensorflow.python.ops import string_ops
 from tensorflow.python.ops import variables
 from tensorflow.python.platform import test
 from tensorflow.python.training import saver
@@ -488,6 +490,82 @@ class KeyValueTensorInitializerTest(BaseLookupTableTest):
       self.initialize_table(table)
 
 
+class DatasetInitializerTest(BaseLookupTableTest):
+
+  def _createVocabFile(self, basename, values=("brain", "salad", "surgery")):
+    vocabulary_file = os.path.join(self.get_temp_dir(), basename)
+    with open(vocabulary_file, "w") as f:
+      f.write("\n".join(values) + "\n")
+    return vocabulary_file
+
+  def test_basic(self):
+    keys = dataset_ops.Dataset.range(100)
+    values = dataset_ops.Dataset.range(100).map(
+        lambda x: string_ops.as_string(x * 2))
+    ds = dataset_ops.Dataset.zip((keys, values))
+    init = lookup_ops.DatasetInitializer(ds)
+    table = self.getHashTable()(init, default_value="")
+    self.initialize_table(table)
+
+    output = table.lookup(constant_op.constant([0, 2, 5], dtypes.int64))
+    result = self.evaluate(output)
+    self.assertAllEqual(["0", "4", "10"], result)
+
+  def test_basic_bad_shape(self):
+    keys = dataset_ops.Dataset.range(100)
+    values = dataset_ops.Dataset.range(100).map(
+        lambda x: string_ops.as_string(x * 2))
+    values = values.batch(4)
+    ds = dataset_ops.Dataset.zip((keys, values))
+    with self.assertRaises(ValueError):
+      lookup_ops.DatasetInitializer(ds)
+
+  def test_from_file(self):
+    vocabulary_file = self._createVocabFile("test.txt", ("one", "two", "three"))
+    ds = reader_ops.TextLineDataset(vocabulary_file)
+    ds = ds.enumerate(start=1)
+    init = lookup_ops.DatasetInitializer(ds)
+    table = self.getHashTable()(init, default_value="")
+    self.initialize_table(table)
+
+    output = table.lookup(constant_op.constant([2, 3, 4], dtypes.int64))
+    result = self.evaluate(output)
+    self.assertAllEqual(["two", "three", ""], result)
+
+  def test_from_multiple_files(self):
+    vocabulary_file1 = self._createVocabFile("test1.txt",
+                                             ("one", "two", "three"))
+    vocabulary_file2 = self._createVocabFile("test2.txt",
+                                             ("four", "five", "six"))
+    ds = reader_ops.TextLineDataset([vocabulary_file1, vocabulary_file2])
+    ds = ds.enumerate(start=1)
+    init = lookup_ops.DatasetInitializer(ds)
+    table = self.getHashTable()(init, default_value="")
+    self.initialize_table(table)
+
+    output = table.lookup(constant_op.constant([2, 3, 4], dtypes.int64))
+    result = self.evaluate(output)
+    self.assertAllEqual(["two", "three", "four"], result)
+
+  def test_map_variable(self):
+    ds = dataset_ops.Dataset.range(100)
+    captured_var = variables.Variable(0)
+
+    def func(_):
+      return captured_var.assign_add(1)
+
+    ds = ds.map(func)
+    ds = ds.enumerate(start=1)
+    init = lookup_ops.DatasetInitializer(ds)
+    table = self.getHashTable()(init, default_value=-1)
+    self.evaluate(captured_var.initializer)
+    self.initialize_table(table)
+
+    output = table.lookup(constant_op.constant([1, 2, 101], dtypes.int64))
+    result = self.evaluate(output)
+    self.assertAllEqual([1, 2, -1], result)
+
+
 class InitializeTableFromFileOpTest(BaseLookupTableTest):
 
   def _createVocabFile(self, basename, values=("brain", "salad", "surgery")):

tensorflow/python/ops/lookup_ops.py

@@ -30,6 +30,7 @@ from tensorflow.python.framework import dtypes
 from tensorflow.python.framework import ops
 from tensorflow.python.framework import sparse_tensor
 from tensorflow.python.framework import tensor_shape
+from tensorflow.python.framework import tensor_spec
 from tensorflow.python.framework import tensor_util
 from tensorflow.python.ops import array_ops
 from tensorflow.python.ops import control_flow_ops
@@ -411,6 +412,65 @@ class TableInitializerBase(trackable_base.Trackable):
     return shared_name
 
 
+@tf_export("lookup.experimental.DatasetInitializer")
+class DatasetInitializer(TableInitializerBase):
+  """Creates a table initializer from a `tf.data.Dataset`.
+
+  Sample usage:
+  ```python
+    keys = tf.data.Dataset.range(100)
+    values = tf.data.Dataset.range(100).map(
+        lambda x: string_ops.as_string(x * 2))
+    ds = tf.data.Dataset.zip((keys, values))
+    init = tf.lookup.experimental.DatasetInitializer(ds)
+    table = tf.lookup.StaticHashTable(init, "")
+    output = table.lookup([0, 1, 2])
+    assertEquals(outputs, ["0", "2", "4"])
+  ```
+
+  Attributes:
+    dataset: A `tf.data.Dataset` object that produces tuples of scalars. The
+      first scalar is treated as a key and the second as value.
+
+  Raises: ValueError if `dataset` doesn't conform to specifications.
+  """
+
+  def __init__(self, dataset):
+    """Creates a table initializser from a `tf.data.Dataset`.
+
+    Args:
+      dataset: A `tf.data.Dataset` object that produces tuples of scalars. The
+      first scalar is treated as a key and the second as value.
+
+    Raises: ValueError if `dataset` doesn't conform to specifications.
+    Returns: A `DatasetInitializer` object
+    """
+    # Assert that the dataset element spec is a tuple of TensorSpecs where
+    # each tensor is a scalar.
+    self.dataset = dataset
+    elem_spec = self.dataset.element_spec
+    if len(elem_spec) != 2:
+      raise ValueError("element spec size should be 2")
+    if not isinstance(elem_spec[0], tensor_spec.TensorSpec):
+      raise ValueError("elem_spec[0] should be of type TensorSpec")
+    if not isinstance(elem_spec[1], tensor_spec.TensorSpec):
+      raise ValueError("elem_spec[1] should be of type TensorSpec")
+    if elem_spec[0].shape.rank not in (None, 0):
+      raise ValueError("key tensor should be a scalar")
+    if elem_spec[1].shape.rank not in (None, 0):
+      raise ValueError("value tensor should be a scalar")
+
+    key_type = elem_spec[0].dtype
+    value_type = elem_spec[1].dtype
+    super(DatasetInitializer, self).__init__(key_type, value_type)
+
+  def initialize(self, table):
+    _check_table_dtypes(table, self._key_dtype, self._value_dtype)
+    init_op = gen_lookup_ops.initialize_table_from_dataset(
+        table.resource_handle, self.dataset._variant_tensor)  # pylint: disable=protected-access
+    return init_op
+
+
 @tf_export("lookup.KeyValueTensorInitializer")
 class KeyValueTensorInitializer(TableInitializerBase):
   """Table initializers given `keys` and `values` tensors."""

tensorflow/tools/api/golden/v1/tensorflow.lookup.experimental.-dataset-initializer.pbtxt

@@ -0,0 +1,23 @@
+path: "tensorflow.lookup.experimental.DatasetInitializer"
+tf_class {
+  is_instance: "<class \'tensorflow.python.ops.lookup_ops.DatasetInitializer\'>"
+  is_instance: "<class \'tensorflow.python.ops.lookup_ops.TableInitializerBase\'>"
+  is_instance: "<class \'tensorflow.python.training.tracking.base.Trackable\'>"
+  is_instance: "<type \'object\'>"
+  member {
+    name: "key_dtype"
+    mtype: "<type \'property\'>"
+  }
+  member {
+    name: "value_dtype"
+    mtype: "<type \'property\'>"
+  }
+  member_method {
+    name: "__init__"
+    argspec: "args=[\'self\', \'dataset\'], varargs=None, keywords=None, defaults=None"
+  }
+  member_method {
+    name: "initialize"
+    argspec: "args=[\'self\', \'table\'], varargs=None, keywords=None, defaults=None"
+  }
+}

tensorflow/tools/api/golden/v1/tensorflow.lookup.experimental.pbtxt

@@ -1,5 +1,9 @@
 path: "tensorflow.lookup.experimental"
 tf_module {
+  member {
+    name: "DatasetInitializer"
+    mtype: "<type \'type\'>"
+  }
   member {
     name: "DenseHashTable"
     mtype: "<type \'type\'>"

tensorflow/tools/api/golden/v1/tensorflow.raw_ops.pbtxt

@@ -1816,6 +1816,10 @@ tf_module {
     name: "InitializeTable"
     argspec: "args=[\'table_handle\', \'keys\', \'values\', \'name\'], varargs=None, keywords=None, defaults=[\'None\'], "
   }
+  member_method {
+    name: "InitializeTableFromDataset"
+    argspec: "args=[\'table_handle\', \'dataset\', \'name\'], varargs=None, keywords=None, defaults=[\'None\'], "
+  }
   member_method {
     name: "InitializeTableFromTextFile"
     argspec: "args=[\'table_handle\', \'filename\', \'key_index\', \'value_index\', \'vocab_size\', \'delimiter\', \'name\'], varargs=None, keywords=None, defaults=[\'-1\', \'\\t\', \'None\'], "

tensorflow/tools/api/golden/v2/tensorflow.lookup.experimental.-dataset-initializer.pbtxt

@@ -0,0 +1,23 @@
+path: "tensorflow.lookup.experimental.DatasetInitializer"
+tf_class {
+  is_instance: "<class \'tensorflow.python.ops.lookup_ops.DatasetInitializer\'>"
+  is_instance: "<class \'tensorflow.python.ops.lookup_ops.TableInitializerBase\'>"
+  is_instance: "<class \'tensorflow.python.training.tracking.base.Trackable\'>"
+  is_instance: "<type \'object\'>"
+  member {
+    name: "key_dtype"
+    mtype: "<type \'property\'>"
+  }
+  member {
+    name: "value_dtype"
+    mtype: "<type \'property\'>"
+  }
+  member_method {
+    name: "__init__"
+    argspec: "args=[\'self\', \'dataset\'], varargs=None, keywords=None, defaults=None"
+  }
+  member_method {
+    name: "initialize"
+    argspec: "args=[\'self\', \'table\'], varargs=None, keywords=None, defaults=None"
+  }
+}

tensorflow/tools/api/golden/v2/tensorflow.lookup.experimental.pbtxt

@@ -1,5 +1,9 @@
 path: "tensorflow.lookup.experimental"
 tf_module {
+  member {
+    name: "DatasetInitializer"
+    mtype: "<type \'type\'>"
+  }
   member {
     name: "DenseHashTable"
     mtype: "<type \'type\'>"

tensorflow/tools/api/golden/v2/tensorflow.raw_ops.pbtxt

@@ -1816,6 +1816,10 @@ tf_module {
     name: "InitializeTable"
     argspec: "args=[\'table_handle\', \'keys\', \'values\', \'name\'], varargs=None, keywords=None, defaults=[\'None\'], "
   }
+  member_method {
+    name: "InitializeTableFromDataset"
+    argspec: "args=[\'table_handle\', \'dataset\', \'name\'], varargs=None, keywords=None, defaults=[\'None\'], "
+  }
   member_method {
     name: "InitializeTableFromTextFile"
     argspec: "args=[\'table_handle\', \'filename\', \'key_index\', \'value_index\', \'vocab_size\', \'delimiter\', \'name\'], varargs=None, keywords=None, defaults=[\'-1\', \'\\t\', \'None\'], "