Expose stream-ordering in nvtext API (#17446)

Adds stream parameter to
```
cudf::nvtext::byte_pair_encoding
```
Added stream gtests to verify correct stream forwarding.

Reference: #13744

Authors:
  - Shruti Shivakumar (https://github.com/shrshi)
  - David Wendt (https://github.com/davidwendt)

Approvers:
  - Yunsong Wang (https://github.com/PointKernel)
  - David Wendt (https://github.com/davidwendt)

URL: #17446

cpp/include/nvtext/byte_pair_encoding.hpp

@@ -122,13 +122,15 @@ std::unique_ptr<bpe_merge_pairs> load_merge_pairs(
  * @param merges_pairs Created by a call to @ref nvtext::load_merge_pairs.
  * @param separator String used to build the output after encoding.
  *                  Default is a space.
+ * @param stream CUDA stream used for device memory operations and kernel launches
  * @param mr Memory resource to allocate any returned objects.
  * @return An encoded column of strings.
  */
 std::unique_ptr<cudf::column> byte_pair_encoding(
   cudf::strings_column_view const& input,
   bpe_merge_pairs const& merges_pairs,
   cudf::string_scalar const& separator = cudf::string_scalar(" "),
+  rmm::cuda_stream_view stream         = cudf::get_default_stream(),
   rmm::device_async_resource_ref mr    = cudf::get_current_device_resource_ref());
 
 /** @} */  // end of group

cpp/src/text/bpe/byte_pair_encoding.cu

@@ -459,10 +459,11 @@ std::unique_ptr<cudf::column> byte_pair_encoding(cudf::strings_column_view const
 std::unique_ptr<cudf::column> byte_pair_encoding(cudf::strings_column_view const& input,
                                                  bpe_merge_pairs const& merges_table,
                                                  cudf::string_scalar const& separator,
+                                                 rmm::cuda_stream_view stream,
                                                  rmm::device_async_resource_ref mr)
 {
   CUDF_FUNC_RANGE();
-  return detail::byte_pair_encoding(input, merges_table, separator, cudf::get_default_stream(), mr);
+  return detail::byte_pair_encoding(input, merges_table, separator, stream, mr);
 }
 
 }  // namespace nvtext

cpp/src/text/bpe/load_merge_pairs.cu

@@ -103,7 +103,8 @@ std::unique_ptr<bpe_merge_pairs::bpe_merge_pairs_impl> create_bpe_merge_pairs_im
   rmm::cuda_stream_view stream,
   rmm::device_async_resource_ref mr)
 {
-  auto pairs   = cudf::strings::split_record(input, cudf::string_scalar(" "), 1, stream, mr);
+  auto pairs =
+    cudf::strings::split_record(input, cudf::string_scalar(" ", true, stream, mr), 1, stream, mr);
   auto content = pairs->release();
   return create_bpe_merge_pairs_impl(std::move(content.children.back()), stream);
 }

cpp/tests/CMakeLists.txt

@@ -742,6 +742,7 @@ ConfigureTest(
 )
 ConfigureTest(
   STREAM_TEXT_TEST
+  streams/text/bpe_test.cpp
   streams/text/edit_distance_test.cpp
   streams/text/ngrams_test.cpp
   streams/text/replace_test.cpp

cpp/tests/streams/text/bpe_test.cpp

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2024, NVIDIA CORPORATION.
+ *
+ * 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 <cudf_test/base_fixture.hpp>
+#include <cudf_test/column_wrapper.hpp>
+#include <cudf_test/default_stream.hpp>
+#include <cudf_test/iterator_utilities.hpp>
+
+#include <cudf/strings/strings_column_view.hpp>
+
+#include <nvtext/byte_pair_encoding.hpp>
+
+struct TextBytePairEncoding : public cudf::test::BaseFixture {};
+
+TEST_F(TextBytePairEncoding, BytePairEncoding)
+{
+  auto stream = cudf::test::get_default_stream();
+  // partial table based on values from https://huggingface.co/gpt2/raw/main/merges.txt
+  auto mpt = cudf::test::strings_column_wrapper({
+    "e n",    // 14
+    "i t",    // 16
+    "i s",    // 17
+    "e s",    // 20
+    "en t",   // 44
+    "c e",    // 90
+    "es t",   // 141
+    "en ce",  // 340
+    "t h",    // 146
+    "h i",    // 5049
+    "th is",  // 5407
+    "t est",  // 9034
+    "s i",    // 13142
+    "s ent"   // 33832
+  });
+
+  auto merge_pairs = nvtext::load_merge_pairs(cudf::strings_column_view(mpt), stream);
+
+  auto validity = cudf::test::iterators::null_at(4);
+  cudf::test::strings_column_wrapper input(
+    {"thisisit", "thisis test-sentence-1", "thisistestsentence-2", "this-istestsentence 3", "", ""},
+    validity);
+  auto sv = cudf::strings_column_view(input);
+
+  auto results =
+    nvtext::byte_pair_encoding(sv, *merge_pairs, cudf::string_scalar(" ", true, stream), stream);
+}