Split reduction kernels

dali/core/partition_test.cc

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+// Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. 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 "dali/core/partition.h"
+#include <gtest/gtest.h>
+#include <vector>
+
+namespace dali {
+
+TEST(MultiPartitionTest, CArray) {
+  const int N = 9;
+  int input[N] = { 5, 6, 3, 5, 10, 0, 3, 4, 5 };
+  int ref[N] =   { 5, 5, 5, 3, 0, 3, 4, 6, 10 };
+  // partition points      ^           ^  ^
+  auto [less_than_5, less_than_7, rest] = multi_partition(
+      input,
+      [](int x) { return x == 5; },
+      [](int x) { return x < 5; },
+      [](int x) { return x < 7; });  // note that reordering these would yield a different result!
+  for (int i = 0; i < N; i++) {
+    EXPECT_EQ(input[i], ref[i]);
+  }
+  EXPECT_EQ(less_than_5, input + 3);
+  EXPECT_EQ(less_than_7, input + 7);
+  EXPECT_EQ(rest, input + 8);
+}
+
+TEST(MultiPartitionTest, Iter) {
+  const int N = 9;
+  std::vector<int> input = { 6, 7, 3, 10, 0, 8, 3, 4, 1 };
+  int ref[]              = { 3, 0, 3, 4, 1, 6, 7, 10, 8 };
+  // partition points       ^              ^           ^
+  auto [less_than_five, more_than_five, ten, rest] = multi_partition(
+      input.begin(), input.end(),
+      [](int x) { return x == 5; },  // no elements satisfy this
+      [](int x) { return x < 5; },
+      [](int x) { return x > 5; },
+      [](int x) { return x == 10; });  // overlaps with previous predicate, should be empty
+  for (int i = 0; i < N; i++) {
+    EXPECT_EQ(input[i], ref[i]);
+  }
+  EXPECT_EQ(less_than_five, input.begin());
+  EXPECT_EQ(more_than_five, input.begin() + 5);
+  EXPECT_EQ(ten, input.end());
+  EXPECT_EQ(rest, input.end());
+}
+
+
+TEST(MultiPartitionTest, Vector) {
+  const int N = 9;
+  std::vector<int> input = { 6, 7, 3, 10, 0, 8, 3, 4, 1 };
+  int ref[]              = { 3, 0, 3, 4, 1, 10, 6, 7, 8 };
+  // partition points       ^              ^   ^     ^
+  auto [less_than_5, ten, less_than_8, rest] = multi_partition(
+      input,
+      [](int x) { return x == 5; },  // no elements satisfy this
+      [](int x) { return x < 5; },
+      [](int x) { return x == 10; },
+      [](int x) { return x < 8; });
+  for (int i = 0; i < N; i++) {
+    EXPECT_EQ(input[i], ref[i]);
+  }
+  EXPECT_EQ(less_than_5, input.begin());
+  EXPECT_EQ(ten,         input.begin() + 5);
+  EXPECT_EQ(less_than_8, input.begin() + 6);
+  EXPECT_EQ(rest,        input.begin() + 8);
+}
+
+}  // namespace dali