Introduced HPC into relevant parts #3
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WalkthroughThis pull request introduces OpenMP support to the Changes
Sequence DiagramsequenceDiagram
participant Search as BreadthFirstSearch
participant OpenMP as OpenMP Runtime
participant Frontier as Search Frontier
Search->>OpenMP: Parallel for loop triggered
OpenMP->>Frontier: Distribute node expansion tasks
Frontier-->>OpenMP: Concurrent child node generation
OpenMP-->>Search: Aggregated search results
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Actionable comments posted: 1
🧹 Nitpick comments (1)
tests/tests.cpp (1)
4-4: Usestd::chronoinstead of OpenMP for timing measurementsIncluding
<omp.h>and usingomp_get_wtime()solely for timing adds unnecessary dependency on OpenMP in your tests. The C++ standard library offers<chrono>for high-resolution timing without external dependencies.Suggested changes:
-#include <omp.h> +#include <chrono>And update the timing code in your tests:
-double start = omp_get_wtime(); +auto start = std::chrono::high_resolution_clock::now(); ... -double end = omp_get_wtime(); +auto end = std::chrono::high_resolution_clock::now(); ... -std::cout << "Time: " << end - start << std::endl; +std::chrono::duration<double> elapsed = end - start; +std::cout << "Time: " << elapsed.count() << " seconds" << std::endl;
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📒 Files selected for processing (3)
CMakeLists.txt(1 hunks)src/search.cpp(2 hunks)tests/tests.cpp(5 hunks)
🧰 Additional context used
🪛 GitHub Actions: C++ CI
tests/tests.cpp
[error] 36-39: Mismatched end line for _ZN22Definitions_State_Test8TestBodyEv function. LCOV coverage data generation failed.
⏰ Context from checks skipped due to timeout of 90000ms (1)
- GitHub Check: build
🔇 Additional comments (5)
src/search.cpp (1)
10-10: Ensure OpenMP is supported in your build environmentThe inclusion of
#include <omp.h>requires that your compiler and build environment support OpenMP. Make sure that the appropriate compiler flags (e.g.,-fopenmpfor GCC/Clang) are set in your build configuration.tests/tests.cpp (3)
22-22: Verify the impact of increasing the goal value on test performanceChanging the goal value from
10to10010ingoal_testsignificantly increases the search depth required to find a solution. This can lead to longer execution times and higher resource consumption during testing, especially for uninformed search algorithms like Breadth-First Search.Please confirm that this change is intentional and that the tests still complete within an acceptable time frame.
32-32: Ensure heuristic remains admissible with updated goal valueUpdating the heuristic function to return
10010 - test_state->valuealigns it with the new goal value. However, it's important to verify that the heuristic remains admissible (never overestimates the true cost) and consistent to guarantee the optimality and efficiency of algorithms like A* Search.Please ensure that the heuristic accurately reflects the minimal cost to reach the goal from any given state.
44-49: Investigate pipeline failure related to code coverageThe pipeline reports a failure in LCOV coverage data generation with a mismatched end line error. This issue might be related to the inclusion of OpenMP directives or the use of
omp_get_wtime()in the tests.Consider the following steps to troubleshoot:
- Remove the dependency on OpenMP in tests by using
std::chronofor timing, as suggested earlier.- Ensure that your code coverage tools are configured to handle any parallel code correctly.
- Verify that all source files are being compiled with the same settings used during coverage analysis.
Also applies to: 56-61, 70-70
CMakeLists.txt (1)
17-22: OpenMP integration in CMake is correctly implementedThe addition of OpenMP support in your CMake configuration is properly done. The
find_package(OpenMP)command searches for OpenMP, and conditional linking withtarget_link_librariesensures compatibility when OpenMP is available.
| @@ -60,6 +61,7 @@ std::shared_ptr<Node> BreadthFirstSearch::search() { | |||
| if (problem->goal_test(state)) { | |||
| return node; | |||
| } | |||
| #pragma omp parallel for shared(frontier) schedule(dynamic) if (frontier.size() > 1000) | |||
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Potential data race on frontier due to concurrent modifications
The use of #pragma omp parallel for introduces parallelism when iterating over problem->actions(node->state). However, the frontier queue is being modified concurrently by multiple threads with frontier.push(child);. Since std::queue is not thread-safe, this can lead to data races and undefined behavior.
To address this issue, consider collecting child nodes in a thread-local container and then merging them into frontier after the parallel region. Here's a suggested fix:
while (!frontier.empty()) {
auto node = frontier.front();
frontier.pop();
State *state = node->state.get();
if (problem->goal_test(state)) {
return node;
}
+ std::vector<std::shared_ptr<Node>> local_children;
#pragma omp parallel for schedule(dynamic) if (frontier.size() > 1000)
for (size_t i = 0; i < problem->actions(node->state).size(); ++i) {
const auto &action = problem->actions(node->state)[i];
auto child = std::make_shared<Node>(
node,
action->effect,
action,
node->path_cost + action->cost,
problem->heuristic(action->effect.get())
);
- frontier.push(child);
+ #pragma omp critical
+ {
+ local_children.push_back(child);
+ }
}
+ for (const auto& child : local_children) {
+ frontier.push(child);
+ }
}Alternatively, you might use locks or a thread-safe queue to manage concurrent access to frontier, but be mindful of the potential performance implications.
Committable suggestion skipped: line range outside the PR's diff.
This pull request introduces OpenMP parallelism to the project, modifies the goal test and heuristic values in the test suite, and adds timing measurements to the search tests. The most important changes include adding OpenMP support, updating the goal test and heuristic values, and measuring execution time in tests.
Parallelism and Performance Improvements:
CMakeLists.txt: Added OpenMP support by finding the OpenMP package and linking it to thesymphonytarget if found.src/search.cpp: Included the OpenMP header and added a parallel for loop with dynamic scheduling for the breadth-first search algorithm. [1] [2]Test Suite Modifications:
tests/tests.cpp: Updated the goal test and heuristic values in theTestProblemclass to use 10010 instead of 10. [1] [2]tests/tests.cpp: Added timing measurements usingomp_get_wtime()to the A* search and breadth-first search tests to measure and print the execution time.These changes aim to enhance the performance of the search algorithms through parallelism and provide more accurate test results with updated values and performance metrics.
Summary by CodeRabbit
New Features
Performance Improvements
Test Updates