first draft example

cpp/tests/CMakeLists.txt

@@ -74,6 +74,8 @@ function(ConfigureTest CMAKE_TEST_NAME)
   )
 endfunction()
 
+ConfigureTest(BLOG blog/example.cpp)
+
 # ##################################################################################################
 # test sources ##################################################################################
 # ##################################################################################################

cpp/tests/blog/example.cpp

@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 2023, 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_utilities.hpp>
+
+#include <cudf/aggregation.hpp>
+#include <cudf/ast/expressions.hpp>
+#include <cudf/column/column_view.hpp>
+#include <cudf/copying.hpp>
+#include <cudf/groupby.hpp>
+#include <cudf/io/json.hpp>
+#include <cudf/join.hpp>
+#include <cudf/sorting.hpp>
+#include <cudf/stream_compaction.hpp>
+#include <cudf/table/table_view.hpp>
+#include <cudf/transform.hpp>
+
+struct BlogExample : public cudf::test::BaseFixture {};
+
+void write_json(cudf::table_view tbl, std::string path)
+{
+  // write the data for inspection
+  auto sink_info = cudf::io::sink_info(path);
+  auto builder2  = cudf::io::json_writer_options::builder(sink_info, tbl).lines(true);
+  auto options2  = builder2.build();
+  cudf::io::write_json(options2);
+}
+
+std::unique_ptr<cudf::table> nunique_func(cudf::table_view tbl)  // group nunique + filter > 1
+{
+  // do the nunique aggregation
+  auto keys = cudf::table_view{{tbl.column(0)}};
+  auto val  = tbl.column(1);
+  cudf::groupby::groupby grpby_obj(keys);
+  std::vector<cudf::groupby::aggregation_request> requests;
+  requests.emplace_back(cudf::groupby::aggregation_request());
+  auto agg = cudf::make_nunique_aggregation<cudf::groupby_aggregation>();
+  requests[0].aggregations.push_back(std::move(agg));
+  requests[0].values = val;
+  auto agg_results   = grpby_obj.aggregate(requests);
+  auto result_key    = std::move(agg_results.first);
+  auto result_val    = std::move(agg_results.second[0].results[0]);
+  std::vector<cudf::column_view> columns{result_key->get_column(0), *result_val};
+  auto agg_v = cudf::table_view(columns);
+
+  // filter out the keys with nunique > 1
+  auto const op      = cudf::ast::ast_operator::EQUAL;
+  auto literal_value = cudf::numeric_scalar<int32_t>(1);
+  auto literal       = cudf::ast::literal(literal_value);
+  auto col_ref_1     = cudf::ast::column_reference(1);
+  auto expression    = cudf::ast::operation(op, col_ref_1, literal);
+  auto boolean_mask  = cudf::compute_column(agg_v, expression);
+  auto filtered      = cudf::apply_boolean_mask(agg_v, boolean_mask->view());
+
+  // semi join to gather only those keys from the original table
+  auto join_indices      = cudf::left_semi_join(cudf::table_view{{tbl.column(0)}},
+                                           cudf::table_view{{filtered->view().column(0)}});
+  auto left_indices_span = cudf::device_span<cudf::size_type const>{*join_indices};
+  auto left_indices_col  = cudf::column_view{left_indices_span};
+  auto filtered2         = cudf::gather(tbl, left_indices_col);
+
+  write_json(*filtered2, "/home/nfs/dgala/cudf/cpp/tests/blog/unique_filter.json");
+
+  return filtered2;
+}
+
+std::unique_ptr<cudf::table> max_func(cudf::table_view tbl)  // groupby max + filter >= 0.8
+{
+  // do the groupbymax aggregation
+  auto keys = cudf::table_view{{tbl.column(0)}};
+  auto val  = tbl.column(2);
+  cudf::groupby::groupby grpby_obj(keys);
+  std::vector<cudf::groupby::aggregation_request> requests;
+  requests.emplace_back(cudf::groupby::aggregation_request());
+  auto agg = cudf::make_max_aggregation<cudf::groupby_aggregation>();
+  requests[0].aggregations.push_back(std::move(agg));
+  requests[0].values = val;
+  auto agg_results   = grpby_obj.aggregate(requests);
+  auto result_key    = std::move(agg_results.first);
+  auto result_val    = std::move(agg_results.second[0].results[0]);
+  std::vector<cudf::column_view> columns{result_key->get_column(0), *result_val};
+  auto agg_v = cudf::table_view(columns);
+
+  // filter out the keys with nunique > 1
+  auto const op      = cudf::ast::ast_operator::GREATER_EQUAL;
+  auto literal_value = cudf::numeric_scalar<double>(0.8);
+  auto literal       = cudf::ast::literal(literal_value);
+  auto col_ref_1     = cudf::ast::column_reference(1);
+  auto expression    = cudf::ast::operation(op, col_ref_1, literal);
+  auto boolean_mask  = cudf::compute_column(agg_v, expression);
+  auto filtered      = cudf::apply_boolean_mask(agg_v, boolean_mask->view());
+
+  // semi join to gather only those keys from the original table
+  auto join_indices      = cudf::left_semi_join(cudf::table_view{{tbl.column(0)}},
+                                           cudf::table_view{{filtered->view().column(0)}});
+  auto left_indices_span = cudf::device_span<cudf::size_type const>{*join_indices};
+  auto left_indices_col  = cudf::column_view{left_indices_span};
+  auto filtered2         = cudf::gather(tbl, left_indices_col);
+
+  // write the data for inspection
+  write_json(*filtered2, "/home/nfs/dgala/cudf/cpp/tests/blog/max_greater_filter.json");
+
+  return filtered2;
+}
+
+void sort_func(cudf::table_view tbl)
+{
+  auto sorted_tbl = cudf::sort(tbl);
+
+  write_json(*sorted_tbl, "/home/nfs/dgala/cudf/cpp/tests/blog/sort.json");
+}
+
+TEST_F(BlogExample, Test)
+{
+  // load the json from the example
+  auto source_info = cudf::io::source_info("/home/nfs/dgala/cudf/cpp/tests/blog/example.json");
+  auto builder     = cudf::io::json_reader_options::builder(source_info).lines(true);
+  auto options     = builder.build();
+  auto json        = cudf::io::read_json(options);
+  auto tbl         = json.tbl->view();
+
+  auto nunique_result = nunique_func(tbl);
+
+  auto max_result = max_func(nunique_result->view());
+
+  sort_func(max_result->view());
+}

cpp/tests/blog/example.json

@@ -0,0 +1,5 @@
+{"features": {"key":"a1", "value": [{"info":"message_1", "type": "device_a", "dt": 1688750001}]}, "source": "network_a", "quality": 0.7}
+{"features": {"key":"a2", "value": [{"info":"message_2", "type": "device_a", "dt": 1688750002}]}, "source": "network_a", "quality": 0.7}
+{"features": {"key":"a3", "value": [{"info":"message_3", "type": "device_a", "dt": 1688750003}]}, "source": "network_b", "quality": 0.8}
+{"features": {"key":"a1", "value": [{"info":"message_1", "type": "device_a", "dt": 1688750001}]}, "source": "network_b", "quality": 0.9}
+{"features": {"key":"a4", "value": [{"info":"message_4", "type": "device_a", "dt": 1688750004}]}, "source": "network_b", "quality": 0.9}

cpp/tests/blog/max_greater_filter.json

@@ -0,0 +1,2 @@
+{"0":{"0":"a3","1":[{"0":"message_3","1":"device_a","2":1688750003}]},"1":"network_b","2":0.8}
+{"0":{"0":"a4","1":[{"0":"message_4","1":"device_a","2":1688750004}]},"1":"network_b","2":0.9}

cpp/tests/blog/sort.json

@@ -0,0 +1,2 @@
+{"0":{"0":"a3","1":[{"0":"message_3","1":"device_a","2":1688750003}]},"1":"network_b","2":0.8}
+{"0":{"0":"a4","1":[{"0":"message_4","1":"device_a","2":1688750004}]},"1":"network_b","2":0.9}

cpp/tests/blog/unique_filter.json

@@ -0,0 +1,3 @@
+{"0":{"0":"a2","1":[{"0":"message_2","1":"device_a","2":1688750002}]},"1":"network_a","2":0.7}
+{"0":{"0":"a3","1":[{"0":"message_3","1":"device_a","2":1688750003}]},"1":"network_b","2":0.8}
+{"0":{"0":"a4","1":[{"0":"message_4","1":"device_a","2":1688750004}]},"1":"network_b","2":0.9}