mirror of
https://github.com/ceres-solver/ceres-solver.git
synced 2026-08-29 16:40:38 +08:00
Mike Vitus
dc5ea0ea4d
This is in preparation for adding support for a c++11 based parallel for implementation. The parallel for abstraction does not have the ability to constrain the total number of threads in nested for loops. This is solved by distributing the number of threads evenly between the nested for loops. Adds a TODO to consolidate the next for loops into a single loop that can be properly split between threads. Tested by building with TBB and running tests. Change-Id: I546973b9a4d19b9cdd53caff55d1c80bac8ea953
84 lines
3.0 KiB
C++
84 lines
3.0 KiB
C++
// Ceres Solver - A fast non-linear least squares minimizer
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// Copyright 2018 Google Inc. All rights reserved.
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// http://ceres-solver.org/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// * Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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// * Neither the name of Google Inc. nor the names of its contributors may be
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// used to endorse or promote products derived from this software without
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// specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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//
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// Author: vitus@google.com (Michael Vitus)
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// This include must come before any #ifndef check on Ceres compile options.
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#include "ceres/internal/port.h"
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#ifdef CERES_USE_TBB
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#include "ceres/parallel_for.h"
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#include <vector>
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#include "gmock/gmock.h"
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#include "gtest/gtest.h"
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namespace ceres {
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namespace internal {
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using testing::ElementsAreArray;
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// Tests the parallel for loop computes the correct result for various number of
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// threads.
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TEST(ParallelFor, NumThreads) {
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const int size = 16;
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std::vector<int> expected_results(size, 0);
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for (int i = 0; i < size; ++i) {
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expected_results[i] = std::sqrt(i);
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}
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for (int num_threads = 1; num_threads <= 8; ++num_threads) {
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std::vector<int> values(size, 0);
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ParallelFor(0, size, num_threads,
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[&values](int i) { values[i] = std::sqrt(i); });
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EXPECT_THAT(values, ElementsAreArray(expected_results));
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}
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}
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// Tests nested for loops do not result in a deadlock.
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TEST(ParallelFor, NestedParallelForDeadlock) {
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// Increment each element in the 2D matrix.
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std::vector<std::vector<int>> x(3, {1, 2, 3});
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ParallelFor(0, 3, 2, [&x](int i) {
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std::vector<int>& y = x.at(i);
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ParallelFor(0, 3, 2, [&y](int j) { ++y.at(j); });
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});
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const std::vector<int> results = {2, 3, 4};
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for (const std::vector<int>& value : x) {
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EXPECT_THAT(value, ElementsAreArray(results));
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}
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}
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} // namespace internal
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} // namespace ceres
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#endif // CERES_USE_TBB
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