Squashed 'third_party/ceres/' content from commit e51e9b4
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git-subtree-dir: third_party/ceres
git-subtree-split: e51e9b46f6ca88ab8b2266d0e362771db6d98067
diff --git a/internal/ceres/parallel_for_test.cc b/internal/ceres/parallel_for_test.cc
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+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2018 Google Inc. All rights reserved.
+// http://ceres-solver.org/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+// * Neither the name of Google Inc. nor the names of its contributors may be
+// used to endorse or promote products derived from this software without
+// specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: vitus@google.com (Michael Vitus)
+
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
+#include "ceres/parallel_for.h"
+
+#include <cmath>
+#include <condition_variable>
+#include <mutex>
+#include <thread>
+#include <vector>
+
+#include "ceres/context_impl.h"
+#include "glog/logging.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+namespace ceres {
+namespace internal {
+
+using testing::ElementsAreArray;
+using testing::UnorderedElementsAreArray;
+
+// Tests the parallel for loop computes the correct result for various number of
+// threads.
+TEST(ParallelFor, NumThreads) {
+ ContextImpl context;
+ context.EnsureMinimumThreads(/*num_threads=*/2);
+
+ const int size = 16;
+ std::vector<int> expected_results(size, 0);
+ for (int i = 0; i < size; ++i) {
+ expected_results[i] = std::sqrt(i);
+ }
+
+ for (int num_threads = 1; num_threads <= 8; ++num_threads) {
+ std::vector<int> values(size, 0);
+ ParallelFor(&context, 0, size, num_threads,
+ [&values](int i) { values[i] = std::sqrt(i); });
+ EXPECT_THAT(values, ElementsAreArray(expected_results));
+ }
+}
+
+// Tests the parallel for loop with the thread ID interface computes the correct
+// result for various number of threads.
+TEST(ParallelForWithThreadId, NumThreads) {
+ ContextImpl context;
+ context.EnsureMinimumThreads(/*num_threads=*/2);
+
+ const int size = 16;
+ std::vector<int> expected_results(size, 0);
+ for (int i = 0; i < size; ++i) {
+ expected_results[i] = std::sqrt(i);
+ }
+
+ for (int num_threads = 1; num_threads <= 8; ++num_threads) {
+ std::vector<int> values(size, 0);
+ ParallelFor(&context, 0, size, num_threads,
+ [&values](int thread_id, int i) { values[i] = std::sqrt(i); });
+ EXPECT_THAT(values, ElementsAreArray(expected_results));
+ }
+}
+
+// Tests nested for loops do not result in a deadlock.
+TEST(ParallelFor, NestedParallelForDeadlock) {
+ ContextImpl context;
+ context.EnsureMinimumThreads(/*num_threads=*/2);
+
+ // Increment each element in the 2D matrix.
+ std::vector<std::vector<int>> x(3, {1, 2, 3});
+ ParallelFor(&context, 0, 3, 2, [&x, &context](int i) {
+ std::vector<int>& y = x.at(i);
+ ParallelFor(&context, 0, 3, 2, [&y](int j) { ++y.at(j); });
+ });
+
+ const std::vector<int> results = {2, 3, 4};
+ for (const std::vector<int>& value : x) {
+ EXPECT_THAT(value, ElementsAreArray(results));
+ }
+}
+
+// Tests nested for loops do not result in a deadlock for the parallel for with
+// thread ID interface.
+TEST(ParallelForWithThreadId, NestedParallelForDeadlock) {
+ ContextImpl context;
+ context.EnsureMinimumThreads(/*num_threads=*/2);
+
+ // Increment each element in the 2D matrix.
+ std::vector<std::vector<int>> x(3, {1, 2, 3});
+ ParallelFor(&context, 0, 3, 2, [&x, &context](int thread_id, int i) {
+ std::vector<int>& y = x.at(i);
+ ParallelFor(&context, 0, 3, 2, [&y](int thread_id, int j) { ++y.at(j); });
+ });
+
+ const std::vector<int> results = {2, 3, 4};
+ for (const std::vector<int>& value : x) {
+ EXPECT_THAT(value, ElementsAreArray(results));
+ }
+}
+
+// This test is only valid when multithreading support is enabled.
+#ifndef CERES_NO_THREADS
+TEST(ParallelForWithThreadId, UniqueThreadIds) {
+ // Ensure the hardware supports more than 1 thread to ensure the test will
+ // pass.
+ const int num_hardware_threads = std::thread::hardware_concurrency();
+ if (num_hardware_threads <= 1) {
+ LOG(ERROR)
+ << "Test not supported, the hardware does not support threading.";
+ return;
+ }
+
+ ContextImpl context;
+ context.EnsureMinimumThreads(/*num_threads=*/2);
+ // Increment each element in the 2D matrix.
+ std::vector<int> x(2, -1);
+ std::mutex mutex;
+ std::condition_variable condition;
+ int count = 0;
+ ParallelFor(&context, 0, 2, 2,
+ [&x, &mutex, &condition, &count](int thread_id, int i) {
+ std::unique_lock<std::mutex> lock(mutex);
+ x[i] = thread_id;
+ ++count;
+ condition.notify_all();
+ condition.wait(lock, [&]() { return count == 2; });
+ });
+
+ EXPECT_THAT(x, UnorderedElementsAreArray({0,1}));
+}
+#endif // CERES_NO_THREADS
+
+} // namespace internal
+} // namespace ceres