From 8e85fe418aa40e5e4d4d4700dd491f4cbef4b30e Mon Sep 17 00:00:00 2001
From: Peng Yu <peng.yu@shopify.com>
Date: Wed, 22 Aug 2018 00:05:19 -0400
Subject: [PATCH] add tensor forest inference kernels

---
 tensorflow/core/BUILD                         |   3 +
 ...i_def_TensorForestCreateTreeVariable.pbtxt |  17 +++
 .../api_def_TensorForestTreeDeserialize.pbtxt |  17 +++
 ..._def_TensorForestTreeIsInitializedOp.pbtxt |  17 +++
 .../api_def_TensorForestTreePredict.pbtxt     |  29 ++++
 ...def_TensorForestTreeResourceHandleOp.pbtxt |   5 +
 .../api_def_TensorForestTreeSerialize.pbtxt   |  17 +++
 .../api_def_TensorForestTreeSize.pbtxt        |  17 +++
 tensorflow/core/kernels/BUILD                 |   7 +
 .../kernels/boosted_trees/boosted_trees.proto |  14 ++
 tensorflow/core/kernels/tensor_forest/BUILD   |  53 +++++++
 .../kernels/tensor_forest/prediction_ops.cc   |  93 ++++++++++++
 .../kernels/tensor_forest/resource_ops.cc     | 135 ++++++++++++++++++
 .../core/kernels/tensor_forest/resources.cc   |  59 ++++++++
 .../core/kernels/tensor_forest/resources.h    |  63 ++++++++
 tensorflow/core/ops/tensor_forest_ops.cc      |  79 ++++++++++
 tensorflow/python/BUILD                       |  22 +++
 tensorflow/python/ops/tensor_forest_ops.py    | 110 ++++++++++++++
 18 files changed, 757 insertions(+)
 create mode 100644 tensorflow/core/api_def/base_api/api_def_TensorForestCreateTreeVariable.pbtxt
 create mode 100644 tensorflow/core/api_def/base_api/api_def_TensorForestTreeDeserialize.pbtxt
 create mode 100644 tensorflow/core/api_def/base_api/api_def_TensorForestTreeIsInitializedOp.pbtxt
 create mode 100644 tensorflow/core/api_def/base_api/api_def_TensorForestTreePredict.pbtxt
 create mode 100644 tensorflow/core/api_def/base_api/api_def_TensorForestTreeResourceHandleOp.pbtxt
 create mode 100644 tensorflow/core/api_def/base_api/api_def_TensorForestTreeSerialize.pbtxt
 create mode 100644 tensorflow/core/api_def/base_api/api_def_TensorForestTreeSize.pbtxt
 create mode 100644 tensorflow/core/kernels/tensor_forest/BUILD
 create mode 100644 tensorflow/core/kernels/tensor_forest/prediction_ops.cc
 create mode 100644 tensorflow/core/kernels/tensor_forest/resource_ops.cc
 create mode 100644 tensorflow/core/kernels/tensor_forest/resources.cc
 create mode 100644 tensorflow/core/kernels/tensor_forest/resources.h
 create mode 100644 tensorflow/core/ops/tensor_forest_ops.cc
 create mode 100644 tensorflow/python/ops/tensor_forest_ops.py

diff --git a/tensorflow/core/BUILD b/tensorflow/core/BUILD
index b7ec445e93d..ea99f14aa9c 100644
--- a/tensorflow/core/BUILD
+++ b/tensorflow/core/BUILD
@@ -1038,6 +1038,7 @@ tf_gen_op_libs(
         "batch_ops",
         "bitwise_ops",
         "boosted_trees_ops",
+        "tensor_forest_ops",
         "candidate_sampling_ops",
         "checkpoint_ops",
         "collective_ops",
@@ -1187,6 +1188,7 @@ cc_library(
         ":batch_ops_op_lib",
         ":bitwise_ops_op_lib",
         ":boosted_trees_ops_op_lib",
+        ":tensor_forest_ops_op_lib",
         ":candidate_sampling_ops_op_lib",
         ":checkpoint_ops_op_lib",
         ":collective_ops_op_lib",
@@ -1340,6 +1342,7 @@ cc_library(
         "//tensorflow/core/kernels:batch_kernels",
         "//tensorflow/core/kernels:bincount_op",
         "//tensorflow/core/kernels:boosted_trees_ops",
+        "//tensorflow/core/kernels:tensor_forest_ops",
         "//tensorflow/core/kernels:candidate_sampler_ops",
         "//tensorflow/core/kernels:checkpoint_ops",
         "//tensorflow/core/kernels:collective_ops",
diff --git a/tensorflow/core/api_def/base_api/api_def_TensorForestCreateTreeVariable.pbtxt b/tensorflow/core/api_def/base_api/api_def_TensorForestCreateTreeVariable.pbtxt
new file mode 100644
index 00000000000..fe2ccd9da62
--- /dev/null
+++ b/tensorflow/core/api_def/base_api/api_def_TensorForestCreateTreeVariable.pbtxt
@@ -0,0 +1,17 @@
+op {
+  graph_op_name: "TensorForestCreateTreeVariable"
+  visibility: HIDDEN
+  in_arg {
+    name: "tree_handle"
+    description: <<END
+Handle to the tree resource to be created.
+END
+  }
+  in_arg {
+    name: "tree_config"
+    description: <<END
+Serialized proto string of the boosted_trees.Tree.
+END
+  }
+  summary: "Creates a tree resource and returns a handle to it."
+}
diff --git a/tensorflow/core/api_def/base_api/api_def_TensorForestTreeDeserialize.pbtxt b/tensorflow/core/api_def/base_api/api_def_TensorForestTreeDeserialize.pbtxt
new file mode 100644
index 00000000000..43dbcb7b42d
--- /dev/null
+++ b/tensorflow/core/api_def/base_api/api_def_TensorForestTreeDeserialize.pbtxt
@@ -0,0 +1,17 @@
+op {
+  graph_op_name: "TensorForestTreeDeserialize"
+  visibility: HIDDEN
+  in_arg {
+    name: "tree_handle"
+    description: <<END
+Handle to the tree resource to be restored.
+END
+  }
+  in_arg {
+    name: "tree_config"
+    description: <<END
+Serialied proto string of the boosted_trees.Tree proto.
+END
+  }
+  summary: "Deserializes a proto into the tree handle"
+}
diff --git a/tensorflow/core/api_def/base_api/api_def_TensorForestTreeIsInitializedOp.pbtxt b/tensorflow/core/api_def/base_api/api_def_TensorForestTreeIsInitializedOp.pbtxt
new file mode 100644
index 00000000000..f9c7a67888e
--- /dev/null
+++ b/tensorflow/core/api_def/base_api/api_def_TensorForestTreeIsInitializedOp.pbtxt
@@ -0,0 +1,17 @@
+op {
+  graph_op_name: "TensorForestTreeIsInitializedOp"
+  visibility: HIDDEN
+  in_arg {
+    name: "tree_handle"
+    description: <<END
+Handle to the tree.
+END
+  }
+  out_arg {
+    name: "is_initialized"
+    description: <<END
+Whether the tree is initialized.
+END
+  }
+  summary: "Checks whether a tree has been initialized."
+}
diff --git a/tensorflow/core/api_def/base_api/api_def_TensorForestTreePredict.pbtxt b/tensorflow/core/api_def/base_api/api_def_TensorForestTreePredict.pbtxt
new file mode 100644
index 00000000000..e8d92702748
--- /dev/null
+++ b/tensorflow/core/api_def/base_api/api_def_TensorForestTreePredict.pbtxt
@@ -0,0 +1,29 @@
+op {
+  graph_op_name: "TensorForestTreePredict"
+  visibility: HIDDEN
+  attr {
+    name: "logits_dimension"
+    description: <<END
+Scalar, dimension of the logits.
+END
+  }
+  in_arg {
+    name: "tree_handle"
+    description: <<END
+Handle to the tree resource.
+END
+  }
+  in_arg {
+    name: "dense_features"
+    description: <<END
+Rank 2 dense features tensor.
+END
+  }
+  out_arg {
+    name: "logits"
+    description: <<END
+The logits predictions from the tree for each instance in the batch.
+END
+  }
+  summary: "Output the logits for the given input data"
+}
diff --git a/tensorflow/core/api_def/base_api/api_def_TensorForestTreeResourceHandleOp.pbtxt b/tensorflow/core/api_def/base_api/api_def_TensorForestTreeResourceHandleOp.pbtxt
new file mode 100644
index 00000000000..bbf5c51d647
--- /dev/null
+++ b/tensorflow/core/api_def/base_api/api_def_TensorForestTreeResourceHandleOp.pbtxt
@@ -0,0 +1,5 @@
+op {
+  graph_op_name: "TensorForestTreeResourceHandleOp"
+  visibility: HIDDEN
+  summary: "Creates a handle to a TensorForestTreeResource"
+}
diff --git a/tensorflow/core/api_def/base_api/api_def_TensorForestTreeSerialize.pbtxt b/tensorflow/core/api_def/base_api/api_def_TensorForestTreeSerialize.pbtxt
new file mode 100644
index 00000000000..aac2afa0f85
--- /dev/null
+++ b/tensorflow/core/api_def/base_api/api_def_TensorForestTreeSerialize.pbtxt
@@ -0,0 +1,17 @@
+op {
+  graph_op_name: "TensorForestTreeSerialize"
+  visibility: HIDDEN
+  in_arg {
+    name: "tree_handle"
+    description: <<END
+Handle to the tree resource to be serialized.
+END
+  }
+  out_arg {
+    name: "tree_config"
+    description: <<END
+Serialied proto string of the tree resource.
+END
+  }
+  summary: "Serializes the tree handle to a proto"
+}
diff --git a/tensorflow/core/api_def/base_api/api_def_TensorForestTreeSize.pbtxt b/tensorflow/core/api_def/base_api/api_def_TensorForestTreeSize.pbtxt
new file mode 100644
index 00000000000..6b85b0ed6cf
--- /dev/null
+++ b/tensorflow/core/api_def/base_api/api_def_TensorForestTreeSize.pbtxt
@@ -0,0 +1,17 @@
+op {
+  graph_op_name: "TensorForestTreeSize"
+  visibility: HIDDEN
+  in_arg {
+    name: "tree_handle"
+    description: <<END
+Handle to the tree resource.
+END
+  }
+  out_arg {
+    name: "tree_size"
+    description: <<END
+The size of the tree.
+END
+  }
+  summary: "Get the number of nodes in a tree"
+}
diff --git a/tensorflow/core/kernels/BUILD b/tensorflow/core/kernels/BUILD
index 18d70422a0b..078d65dc69d 100644
--- a/tensorflow/core/kernels/BUILD
+++ b/tensorflow/core/kernels/BUILD
@@ -6695,6 +6695,13 @@ tf_kernel_library(
     ],
 )
 
+tf_kernel_library(
+    name = "tensor_forest_ops",
+    deps = [
+        "//tensorflow/core/kernels/tensor_forest:tensor_forest_ops",
+    ],
+)
+
 tf_kernel_library(
     name = "dataset_ops",
     deps = [
diff --git a/tensorflow/core/kernels/boosted_trees/boosted_trees.proto b/tensorflow/core/kernels/boosted_trees/boosted_trees.proto
index 1ab72af0591..4e9bab3e21f 100644
--- a/tensorflow/core/kernels/boosted_trees/boosted_trees.proto
+++ b/tensorflow/core/kernels/boosted_trees/boosted_trees.proto
@@ -12,6 +12,7 @@ message Node {
     Leaf leaf = 1;
     BucketizedSplit bucketized_split = 2;
     CategoricalSplit categorical_split = 3;
+    DenseSplit dense_split = 4;
   }
   NodeMetadata metadata = 777;
 }
@@ -70,6 +71,19 @@ message CategoricalSplit {
   int32 right_id = 4;
 }
 
+// TODO(nponomareva): move out of boosted_trees and rename to trees.proto
+message DenseSplit {
+  // Float feature column and split threshold describing
+  // the rule feature <= threshold.
+  int32 feature_id = 1;
+  float threshold = 2;
+
+  // Node children indexing into a contiguous
+  // vector of nodes starting from the root.
+  int32 left_id = 3;
+  int32 right_id = 4;
+}
+
 // Tree describes a list of connected nodes.
 // Node 0 must be the root and can carry any payload including a leaf
 // in the case of representing the bias.
diff --git a/tensorflow/core/kernels/tensor_forest/BUILD b/tensorflow/core/kernels/tensor_forest/BUILD
new file mode 100644
index 00000000000..df035506f76
--- /dev/null
+++ b/tensorflow/core/kernels/tensor_forest/BUILD
@@ -0,0 +1,53 @@
+# Description:
+#   OpKernels for tensor forest ops.
+
+package(
+    default_visibility = ["//tensorflow:internal"],
+)
+
+licenses(["notice"])  # Apache 2.0
+
+load("//tensorflow:tensorflow.bzl", "tf_kernel_library")
+
+cc_library(
+    name = "resources",
+    srcs = ["resources.cc"],
+    hdrs = ["resources.h"],
+    deps = [
+        "//tensorflow/core:framework",
+        "//tensorflow/core:lib",
+        "//tensorflow/core/kernels/boosted_trees:boosted_trees_proto_cc",
+    ],
+)
+
+tf_kernel_library(
+    name = "resource_ops",
+    srcs = ["resource_ops.cc"],
+    deps = [
+        ":resources",
+        "//tensorflow/core:framework",
+        "//tensorflow/core:lib",
+        "//tensorflow/core:tensor_forest_ops_op_lib",
+        "//tensorflow/core/kernels/boosted_trees:boosted_trees_proto_cc",
+    ],
+)
+
+tf_kernel_library(
+    name = "prediction_ops",
+    srcs = ["prediction_ops.cc"],
+    deps = [
+        ":resources",
+        "//tensorflow/core:framework",
+        "//tensorflow/core:lib",
+        "//tensorflow/core:tensor_forest_ops_op_lib",
+        "//tensorflow/core/kernels/boosted_trees:boosted_trees_proto_cc",
+    ],
+)
+
+tf_kernel_library(
+    name = "tensor_forest_ops",
+    deps = [
+        ":prediction_ops",
+        ":resource_ops",
+    ],
+)
diff --git a/tensorflow/core/kernels/tensor_forest/prediction_ops.cc b/tensorflow/core/kernels/tensor_forest/prediction_ops.cc
new file mode 100644
index 00000000000..877dfbc020d
--- /dev/null
+++ b/tensorflow/core/kernels/tensor_forest/prediction_ops.cc
@@ -0,0 +1,93 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+#include "tensorflow/core/framework/op_kernel.h"
+#include "tensorflow/core/framework/resource_mgr.h"
+#include "tensorflow/core/framework/tensor.h"
+#include "tensorflow/core/framework/tensor_shape.h"
+#include "tensorflow/core/framework/tensor_types.h"
+#include "tensorflow/core/kernels/tensor_forest/resources.h"
+#include "tensorflow/core/platform/thread_annotations.h"
+#include "tensorflow/core/util/work_sharder.h"
+
+namespace tensorflow {
+
+class TensorForestTreePredictOp : public OpKernel {
+ public:
+  explicit TensorForestTreePredictOp(OpKernelConstruction* context)
+      : OpKernel(context) {
+    OP_REQUIRES_OK(context,
+                   context->GetAttr("logits_dimension", &logits_dimension_));
+  }
+
+  void Compute(OpKernelContext* context) override {
+    TensorForestTreeResource* decision_tree_resource;
+    OP_REQUIRES_OK(context, LookupResource(context, HandleFromInput(context, 0),
+                                           &decision_tree_resource));
+    mutex_lock l(*decision_tree_resource->get_mutex());
+    core::ScopedUnref unref_me(decision_tree_resource);
+
+    const Tensor* dense_features_t = nullptr;
+    OP_REQUIRES_OK(context,
+                   context->input("dense_features", &dense_features_t));
+
+    auto dense_features = dense_features_t->matrix<float>();
+    const int32 batch_size = dense_features_t->dim_size(0);
+
+    Tensor* output_predictions = nullptr;
+    OP_REQUIRES_OK(context,
+                   context->allocate_output(0, {batch_size, logits_dimension_},
+                                            &output_predictions));
+    auto out = output_predictions->matrix<float>();
+
+    if (decision_tree_resource->get_size() <= 0) {
+      out.setZero();
+      return;
+    }
+    auto* worker_threads = context->device()->tensorflow_cpu_worker_threads();
+    const int32 num_threads = worker_threads->num_threads;
+
+    // TODO(yupbank): This was from contrib version.
+    //  This cost would probably depend on the depth of the tree we have.
+    //  We will need to run it on a number of trees of diff depth
+    //  and see the num of cpu cycles
+    const int64 cost_per_traverse = 500;
+    auto traverse = [this, &out, &dense_features, decision_tree_resource,
+                     batch_size](int64 start, int64 end) {
+      CHECK_LE(start, end) << "Start exceeding End";
+      CHECK_LE(end, batch_size) << "End exceeding batch size";
+      for (int example_id = start; example_id < end; ++example_id) {
+        const int32 leaf_id =
+            decision_tree_resource->TraverseTree(example_id, &dense_features);
+        set_output_value(example_id, leaf_id, decision_tree_resource, &out);
+      };
+    };
+    Shard(num_threads, worker_threads->workers, batch_size, cost_per_traverse,
+          traverse);
+  };
+
+  void set_output_value(const int32 example_id, const int32 leaf_id,
+                        const TensorForestTreeResource* decision_tree_resource,
+                        TTypes<float>::Matrix* out) const {
+    for (int j = 0; j < logits_dimension_; ++j) {
+      const float logit = decision_tree_resource->get_prediction(leaf_id, j);
+      (*out)(example_id, j) = logit;
+    }
+  };
+
+ private:
+  int32 logits_dimension_;
+};
+
+REGISTER_KERNEL_BUILDER(Name("TensorForestTreePredict").Device(DEVICE_CPU),
+                        TensorForestTreePredictOp);
+
+}  // namespace tensorflow
diff --git a/tensorflow/core/kernels/tensor_forest/resource_ops.cc b/tensorflow/core/kernels/tensor_forest/resource_ops.cc
new file mode 100644
index 00000000000..aba97ea9900
--- /dev/null
+++ b/tensorflow/core/kernels/tensor_forest/resource_ops.cc
@@ -0,0 +1,135 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+#include "tensorflow/core/framework/op_kernel.h"
+#include "tensorflow/core/framework/resource_mgr.h"
+#include "tensorflow/core/framework/tensor.h"
+#include "tensorflow/core/framework/tensor_shape.h"
+#include "tensorflow/core/framework/tensor_types.h"
+#include "tensorflow/core/kernels/tensor_forest/resources.h"
+
+namespace tensorflow {
+
+class TensorForestCreateTreeVariableOp : public OpKernel {
+ public:
+  explicit TensorForestCreateTreeVariableOp(OpKernelConstruction* context)
+      : OpKernel(context){};
+
+  void Compute(OpKernelContext* context) override {
+    const Tensor* tree_config_t;
+    OP_REQUIRES_OK(context, context->input("tree_config", &tree_config_t));
+
+    auto* const result = new TensorForestTreeResource();
+
+    if (!result->InitFromSerialized(tree_config_t->scalar<string>()())) {
+      result->Unref();
+      OP_REQUIRES(context, false,
+                  errors::InvalidArgument("Unable to parse tree config."));
+    }
+
+    // Only create one, if one does not exist already. Report status for all
+    // other exceptions.
+    auto status = CreateResource(context, HandleFromInput(context, 0), result);
+    if (!status.ok() && status.code() != tensorflow::error::ALREADY_EXISTS) {
+      OP_REQUIRES(context, false, status);
+    }
+  }
+};
+
+// Op for serializing a model.
+class TensorForestTreeSerializeOp : public OpKernel {
+ public:
+  explicit TensorForestTreeSerializeOp(OpKernelConstruction* context)
+      : OpKernel(context) {}
+
+  void Compute(OpKernelContext* context) override {
+    TensorForestTreeResource* decision_tree_resource;
+    OP_REQUIRES_OK(context, LookupResource(context, HandleFromInput(context, 0),
+                                           &decision_tree_resource));
+    mutex_lock l(*decision_tree_resource->get_mutex());
+    core::ScopedUnref unref_me(decision_tree_resource);
+    Tensor* output_config_t = nullptr;
+    OP_REQUIRES_OK(
+        context, context->allocate_output(0, TensorShape(), &output_config_t));
+    output_config_t->scalar<string>()() =
+        decision_tree_resource->decision_tree().SerializeAsString();
+  }
+};
+
+// Op for deserializing a tree variable from a checkpoint.
+class TensorForestTreeDeserializeOp : public OpKernel {
+ public:
+  explicit TensorForestTreeDeserializeOp(OpKernelConstruction* context)
+      : OpKernel(context) {}
+  void Compute(OpKernelContext* context) override {
+    TensorForestTreeResource* decision_tree_resource;
+    OP_REQUIRES_OK(context, LookupResource(context, HandleFromInput(context, 0),
+                                           &decision_tree_resource));
+
+    mutex_lock l(*decision_tree_resource->get_mutex());
+    core::ScopedUnref unref_me(decision_tree_resource);
+
+    const Tensor* tree_config_t;
+    OP_REQUIRES_OK(context, context->input("tree_config", &tree_config_t));
+
+    // Deallocate all the previous objects on the resource.
+    decision_tree_resource->Reset();
+
+    if (!decision_tree_resource->InitFromSerialized(
+            tree_config_t->scalar<string>()())) {
+      OP_REQUIRES(context, false,
+                  errors::InvalidArgument("Unable to parse tree config."));
+    }
+  }
+};
+
+// Op for getting tree size.
+class TensorForestTreeSizeOp : public OpKernel {
+ public:
+  explicit TensorForestTreeSizeOp(OpKernelConstruction* context)
+      : OpKernel(context) {}
+
+  void Compute(OpKernelContext* context) override {
+    TensorForestTreeResource* decision_tree_resource;
+    OP_REQUIRES_OK(context, LookupResource(context, HandleFromInput(context, 0),
+                                           &decision_tree_resource));
+    mutex_lock l(*decision_tree_resource->get_mutex());
+    core::ScopedUnref unref_me(decision_tree_resource);
+    Tensor* output_t = nullptr;
+    OP_REQUIRES_OK(context,
+                   context->allocate_output(0, TensorShape(), &output_t));
+    output_t->scalar<int32>()() = decision_tree_resource->get_size();
+  }
+};
+
+REGISTER_RESOURCE_HANDLE_KERNEL(TensorForestTreeResource);
+
+REGISTER_KERNEL_BUILDER(
+    Name("TensorForestTreeIsInitializedOp").Device(DEVICE_CPU),
+    IsResourceInitialized<TensorForestTreeResource>);
+
+REGISTER_KERNEL_BUILDER(
+    Name("TensorForestCreateTreeVariable").Device(DEVICE_CPU),
+    TensorForestCreateTreeVariableOp);
+
+REGISTER_KERNEL_BUILDER(Name("TensorForestTreeSerialize").Device(DEVICE_CPU),
+                        TensorForestTreeSerializeOp);
+
+REGISTER_KERNEL_BUILDER(Name("TensorForestTreeDeserialize").Device(DEVICE_CPU),
+                        TensorForestTreeDeserializeOp);
+
+REGISTER_KERNEL_BUILDER(Name("TensorForestTreeSize").Device(DEVICE_CPU),
+                        TensorForestTreeSizeOp);
+
+}  // namespace tensorflow
diff --git a/tensorflow/core/kernels/tensor_forest/resources.cc b/tensorflow/core/kernels/tensor_forest/resources.cc
new file mode 100644
index 00000000000..9f8ceb96200
--- /dev/null
+++ b/tensorflow/core/kernels/tensor_forest/resources.cc
@@ -0,0 +1,59 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#include "tensorflow/core/kernels/tensor_forest/resources.h"
+#include "tensorflow/core/kernels/boosted_trees/boosted_trees.pb.h"
+#include "tensorflow/core/platform/protobuf.h"
+
+namespace tensorflow {
+
+const float TensorForestTreeResource::get_prediction(
+    const int32 id, const int32 dimension_id) const {
+  return decision_tree_->nodes(id).leaf().vector().value(dimension_id);
+};
+
+const int32 TensorForestTreeResource::TraverseTree(
+    const int32 example_id,
+    const TTypes<float>::ConstMatrix* dense_data) const {
+  using boosted_trees::Node;
+  using boosted_trees::Tree;
+  int32 current_id = 0;
+  while (true) {
+    const Node& current = decision_tree_->nodes(current_id);
+    if (current.has_leaf()) {
+      return current_id;
+    };
+    DCHECK_EQ(current.node_case(), Node::kDenseSplit);
+    const auto& split = current.dense_split();
+
+    if ((*dense_data)(example_id, split.feature_id()) <= split.threshold()) {
+      current_id = split.left_id();
+    } else {
+      current_id = split.right_id();
+    }
+  }
+};
+
+bool TensorForestTreeResource::InitFromSerialized(const string& serialized) {
+  return ParseProtoUnlimited(decision_tree_, serialized);
+}
+
+void TensorForestTreeResource::Reset() {
+  arena_.Reset();
+  CHECK_EQ(0, arena_.SpaceAllocated());
+  decision_tree_ = protobuf::Arena::CreateMessage<boosted_trees::Tree>(&arena_);
+}
+
+}  // namespace tensorflow
diff --git a/tensorflow/core/kernels/tensor_forest/resources.h b/tensorflow/core/kernels/tensor_forest/resources.h
new file mode 100644
index 00000000000..34f61b2c0c5
--- /dev/null
+++ b/tensorflow/core/kernels/tensor_forest/resources.h
@@ -0,0 +1,63 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#ifndef TENSORFLOW_CORE_KERNELS_TENSOR_FOREST_RESOURCES_H_
+#define TENSORFLOW_CORE_KERNELS_TENSOR_FOREST_RESOURCES_H_
+
+#include "tensorflow/core/framework/resource_mgr.h"
+#include "tensorflow/core/framework/tensor.h"
+#include "tensorflow/core/kernels/boosted_trees/boosted_trees.pb.h"
+#include "tensorflow/core/lib/strings/strcat.h"
+#include "tensorflow/core/platform/mutex.h"
+#include "tensorflow/core/platform/protobuf.h"
+
+namespace tensorflow {
+
+// Keep a tree ensemble in memory for efficient evaluation and mutation.
+class TensorForestTreeResource : public ResourceBase {
+ public:
+  TensorForestTreeResource()
+      : decision_tree_(
+            protobuf::Arena::CreateMessage<boosted_trees::Tree>(&arena_)){};
+
+  string DebugString() override {
+    return strings::StrCat("TensorForestTree[size=", get_size(), "]");
+  }
+
+  mutex* get_mutex() { return &mu_; }
+
+  bool InitFromSerialized(const string& serialized);
+
+  // Resets the resource and frees the proto.
+  // Caller needs to hold the mutex lock while calling this.
+  void Reset();
+
+  const int32 get_size() const { return decision_tree_->nodes_size(); }
+
+  const boosted_trees::Tree& decision_tree() const { return *decision_tree_; }
+
+  const float get_prediction(const int32 id, const int32 dimension_id) const;
+
+  const int32 TraverseTree(const int32 example_id,
+                           const TTypes<float>::ConstMatrix* dense_data) const;
+
+ protected:
+  mutex mu_;
+  protobuf::Arena arena_;
+  boosted_trees::Tree* decision_tree_;
+};
+
+}  // namespace tensorflow
+#endif  // TENSORFLOW_CORE_KERNELS_TENSOR_FOREST_RESOURCES_H_
diff --git a/tensorflow/core/ops/tensor_forest_ops.cc b/tensorflow/core/ops/tensor_forest_ops.cc
new file mode 100644
index 00000000000..b4b6ba318e9
--- /dev/null
+++ b/tensorflow/core/ops/tensor_forest_ops.cc
@@ -0,0 +1,79 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#include <vector>
+
+#include "tensorflow/core/framework/common_shape_fns.h"
+#include "tensorflow/core/framework/op.h"
+#include "tensorflow/core/framework/resource_mgr.h"
+#include "tensorflow/core/framework/shape_inference.h"
+
+namespace tensorflow {
+
+REGISTER_RESOURCE_HANDLE_OP(TensorForestTreeResource);
+
+REGISTER_OP("TensorForestTreeIsInitializedOp")
+    .Input("tree_handle: resource")
+    .Output("is_initialized: bool")
+    .SetShapeFn([](shape_inference::InferenceContext* c) {
+      shape_inference::ShapeHandle unused_input;
+      TF_RETURN_IF_ERROR(c->WithRank(c->input(0), 0, &unused_input));
+      c->set_output(0, c->Scalar());
+      return Status::OK();
+    });
+
+REGISTER_OP("TensorForestCreateTreeVariable")
+    .Input("tree_handle: resource")
+    .Input("tree_config: string")
+    .SetShapeFn(tensorflow::shape_inference::NoOutputs);
+
+REGISTER_OP("TensorForestTreeSerialize")
+    .Input("tree_handle: resource")
+    .Output("tree_config: string")
+    .SetShapeFn(tensorflow::shape_inference::ScalarShape);
+
+REGISTER_OP("TensorForestTreeDeserialize")
+    .Input("tree_handle: resource")
+    .Input("tree_config: string")
+    .SetShapeFn([](shape_inference::InferenceContext* c) {
+      shape_inference::ShapeHandle unused_input;
+      TF_RETURN_IF_ERROR(c->WithRank(c->input(0), 0, &unused_input));
+      return Status::OK();
+    });
+
+REGISTER_OP("TensorForestTreeSize")
+    .Input("tree_handle: resource")
+    .Output("tree_size: int32")
+    .SetShapeFn(tensorflow::shape_inference::ScalarShape);
+
+REGISTER_OP("TensorForestTreePredict")
+    .Attr("logits_dimension: int")
+    .Input("tree_handle: resource")
+    .Input("dense_features: float")
+    .Output("logits: float")
+    .SetShapeFn([](tensorflow::shape_inference::InferenceContext* c) {
+      shape_inference::ShapeHandle shape_handle;
+      shape_inference::DimensionHandle batch_size = c->UnknownDim();
+
+      TF_RETURN_IF_ERROR(c->WithRank(c->input(1), 2, &shape_handle));
+
+      batch_size = c->Dim(shape_handle, 0);
+
+      int logits_dimension;
+      TF_RETURN_IF_ERROR(c->GetAttr("logits_dimension", &logits_dimension));
+      c->set_output(0, c->Matrix(batch_size, logits_dimension));
+      return Status::OK();
+    });
+}  // namespace tensorflow
diff --git a/tensorflow/python/BUILD b/tensorflow/python/BUILD
index 4fe92262ba6..cfc25513ed9 100644
--- a/tensorflow/python/BUILD
+++ b/tensorflow/python/BUILD
@@ -132,6 +132,7 @@ py_library(
         ":subscribe",
         ":summary",
         ":tensor_array_ops",
+        ":tensor_forest_ops",
         ":test_ops",  # TODO: Break testing code out into separate rule.
         ":tf_cluster",
         ":tf_item",
@@ -1618,6 +1619,14 @@ tf_gen_op_wrapper_private_py(
     ],
 )
 
+tf_gen_op_wrapper_private_py(
+    name = "tensor_forest_ops_gen",
+    visibility = ["//tensorflow:internal"],
+    deps = [
+        "//tensorflow/core:tensor_forest_ops_op_lib",
+    ],
+)
+
 tf_gen_op_wrapper_private_py(
     name = "summary_ops_gen",
     visibility = ["//tensorflow:__subpackages__"],
@@ -1941,6 +1950,19 @@ py_library(
     ],
 )
 
+py_library(
+    name = "tensor_forest_ops",
+    srcs = ["ops/tensor_forest_ops.py"],
+    srcs_version = "PY2AND3",
+    deps = [
+        ":framework",
+        ":ops",
+        ":tensor_forest_ops_gen",
+        ":training",
+        "//tensorflow/core/kernels/boosted_trees:boosted_trees_proto_py",
+    ],
+)
+
 py_library(
     name = "sets",
     srcs = [
diff --git a/tensorflow/python/ops/tensor_forest_ops.py b/tensorflow/python/ops/tensor_forest_ops.py
new file mode 100644
index 00000000000..42f3cdf324a
--- /dev/null
+++ b/tensorflow/python/ops/tensor_forest_ops.py
@@ -0,0 +1,110 @@
+# Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Ops for tensor_forest."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from tensorflow.python.ops import resources
+
+from tensorflow.python import ops
+from tensorflow.python.ops import gen_tensor_forest_ops
+from tensorflow.python.training import saver
+
+
+class TreeVariableSaveable(saver.BaseSaverBuilder.SaveableObject):
+
+  def __init__(self, type_name, name, container, config, resource_handle_func,
+               create_op_func, is_initialized_op_func, serialize_op_func,
+               deserialize_op_func):
+
+    with ops.name_scope(name, type_name) as name:
+      self._resource_handle = resource_handle_func(
+          container, shared_name=name, name=name)
+
+    self._is_initialized_op = is_initialized_op_func(
+        self._resource_handle)
+    tensor = serialize_op_func(self._resource_handle)
+    self._create_op = create_op_func(
+        self._resource_handle,
+        config)
+    # slice_spec is useful for saving a slice from a variable.
+    # It's not meaningful the tree variable. So we just pass an empty
+    # value.
+    slice_spec = ""
+    specs = [saver.BaseSaverBuilder.SaveSpec(tensor, slice_spec, name)]
+    super(TreeVariableSaveable,
+          self).__init__(self._resource_handle, specs, name)
+
+    ops.add_to_collection(
+        ops.GraphKeys.SAVEABLE_OBJECTS, self)
+
+    resources.register_resource(
+        self._resource_handle, self._create_op, self._is_initialized_op)
+    self._deserialize_op_func = deserialize_op_func
+
+  def restore(self, restored_tensors, unused_restored_shapes):
+    """Restores the associated tree from 'restored_tensors'.
+
+    Args:
+      restored_tensors: the tensors that were loaded from a checkpoint.
+      unused_restored_shapes: the shapes this object should conform to after
+        restore. Not meaningful for trees.
+
+    Returns:
+      The operation that restores the state of the tree variable.
+    """
+    with ops.control_dependencies([self._create_op]):
+      return self._deserialize_op_func(
+          self._resource_handle,
+          restored_tensors[0],
+      )
+
+  @property
+  def resource(self):
+    return self._resource_handle
+
+
+def tree_variable(tree_config, name, container=None):
+  return TreeVariableSaveable(
+      "TreeVariable",
+      name,
+      container,
+      tree_config,
+      gen_tensor_forest_ops.tensor_forest_tree_resource_handle_op,
+      gen_tensor_forest_ops.tensor_forest_create_tree_variable,
+      gen_tensor_forest_ops.tensor_forest_tree_is_initialized_op,
+      gen_tensor_forest_ops.tensor_forest_tree_serialize,
+      gen_tensor_forest_ops.tensor_forest_tree_deserialize).resource
+
+
+class ForestVariables(object):
+
+  def __init__(self, params,
+               tree_configs=None):
+
+    self._variables = []
+
+    for i in range(params.n_trees):
+      tree_config = ''
+      if tree_configs is not None:
+        tree_config = tree_configs[i]
+      self._variables.append(tree_variable(
+          tree_config,
+          'tree-%s' % i,
+      ))
+
+  def __getitem__(self, t):
+    return self._variables[t]