mirror of
https://github.com/PX4/PX4-Autopilot.git
synced 2026-05-20 20:03:54 +08:00
feat(lib): dijkstra path planner library
- Takes in buffer of all edge costs - fills the best_cost buffer for all reachable nodes (unreachable = infinite cost) Usage: - Precompute edge costs (polygon expansion, visibility all separate from planning algorithm) - solve - To find best cost from any position: do one more visibility check from that position to all reachable nodes, return the one with smallest total distance (current position to node to goal) - Once waypoint reached, keep looking up next_node until goal reached Todo: - clean up API (raw float buffer really the best? heap allocated array?) - make optimised version for symmetric cost? < half the data
This commit is contained in:
Balduin
@@ -47,6 +47,7 @@ add_subdirectory(conversion EXCLUDE_FROM_ALL)
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add_subdirectory(crc EXCLUDE_FROM_ALL)
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add_subdirectory(crypto EXCLUDE_FROM_ALL)
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add_subdirectory(dataman_client EXCLUDE_FROM_ALL)
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add_subdirectory(dijkstra EXCLUDE_FROM_ALL)
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add_subdirectory(drivers EXCLUDE_FROM_ALL)
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add_subdirectory(field_sensor_bias_estimator EXCLUDE_FROM_ALL)
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add_subdirectory(geo EXCLUDE_FROM_ALL)
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@@ -0,0 +1,40 @@
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############################################################################
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#
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# Copyright (c) 2026 PX4 Development Team. All rights reserved.
|
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#
|
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# Redistribution and use in source and binary forms, with or without
|
||||
# modification, are permitted provided that the following conditions
|
||||
# are met:
|
||||
#
|
||||
# 1. Redistributions of source code must retain the above copyright
|
||||
# notice, this list of conditions and the following disclaimer.
|
||||
# 2. 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.
|
||||
# 3. Neither the name PX4 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.
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||||
#
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############################################################################
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px4_add_library(dijkstra
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dijkstra.cpp
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)
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target_include_directories(dijkstra PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
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px4_add_unit_gtest(SRC DijkstraTest.cpp LINKLIBS dijkstra)
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@@ -0,0 +1,240 @@
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/****************************************************************************
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||||
*
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||||
* Copyright (c) 2026 PX4 Development Team. All rights reserved.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
*
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. 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.
|
||||
* 3. Neither the name PX4 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.
|
||||
*
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||||
****************************************************************************/
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#include <gtest/gtest.h>
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#include <math.h>
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#include "dijkstra.h"
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namespace
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{
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// Helper: assemble cost matrix entries into a row-major buffer. Use INFINITY for
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// missing edges; explicit list of finite (i, j, cost) triples is concise in tests.
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struct Edge { int from, to; float cost; };
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template <int N>
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void makeMatrix(float (&m)[N * N], std::initializer_list<Edge> edges)
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{
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for (int i = 0; i < N * N; ++i) {
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m[i] = INFINITY;
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}
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for (const auto &e : edges) {
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m[e.from * N + e.to] = e.cost;
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}
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}
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} // namespace
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TEST(DijkstraTest, SingleNodeAtGoal)
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{
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constexpr int N = 1;
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float cost[N * N] = { INFINITY };
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float best[N];
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int next[N];
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bool vis[N];
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ASSERT_TRUE(dijkstra::solveBackward(N, 0, cost, best, next, vis));
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EXPECT_FLOAT_EQ(best[0], 0.f);
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EXPECT_EQ(next[0], -1);
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}
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TEST(DijkstraTest, AsymmetricLineGraphForward)
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{
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// 0 -> 1 -> 2, going forward is cheap, going backward is expensive.
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constexpr int N = 3;
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float cost[N * N];
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makeMatrix<N>(cost, {
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{0, 1, 1.f},
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{1, 2, 1.f},
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{1, 0, 100.f},
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{2, 1, 100.f},
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});
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float best[N];
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int next[N];
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bool vis[N];
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ASSERT_TRUE(dijkstra::solveBackward(N, 2, cost, best, next, vis));
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EXPECT_FLOAT_EQ(best[0], 2.f); // 0 -> 1 -> 2 costs 1 + 1
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EXPECT_FLOAT_EQ(best[1], 1.f); // 1 -> 2
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EXPECT_FLOAT_EQ(best[2], 0.f);
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EXPECT_EQ(next[0], 1);
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EXPECT_EQ(next[1], 2);
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EXPECT_EQ(next[2], -1);
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}
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TEST(DijkstraTest, AsymmetricLineGraphReverse)
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{
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// Same matrix as above; with goal = 0, paths must use the expensive back-edges,
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// confirming the solver respects edge direction (uses cost[i][j] = i -> j, not j -> i).
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constexpr int N = 3;
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float cost[N * N];
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makeMatrix<N>(cost, {
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{0, 1, 1.f},
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{1, 2, 1.f},
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{1, 0, 100.f},
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{2, 1, 100.f},
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});
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float best[N];
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int next[N];
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bool vis[N];
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ASSERT_TRUE(dijkstra::solveBackward(N, 0, cost, best, next, vis));
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EXPECT_FLOAT_EQ(best[0], 0.f);
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EXPECT_FLOAT_EQ(best[1], 100.f);
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EXPECT_FLOAT_EQ(best[2], 200.f);
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EXPECT_EQ(next[1], 0);
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EXPECT_EQ(next[2], 1);
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EXPECT_EQ(next[0], -1);
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}
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TEST(DijkstraTest, TriangleWithBlockedEdge)
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{
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// Direct edge 0 -> 2 is cheap; remove it and the solver must route via 1.
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constexpr int N = 3;
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float cost[N * N];
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makeMatrix<N>(cost, {
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{0, 1, 1.f},
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{1, 2, 1.f},
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{0, 2, 0.5f},
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});
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float best[N];
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int next[N];
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bool vis[N];
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ASSERT_TRUE(dijkstra::solveBackward(N, 2, cost, best, next, vis));
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EXPECT_FLOAT_EQ(best[0], 0.5f);
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EXPECT_EQ(next[0], 2);
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// Block the direct edge and re-solve; path must detour through 1.
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cost[0 * N + 2] = INFINITY;
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ASSERT_TRUE(dijkstra::solveBackward(N, 2, cost, best, next, vis));
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EXPECT_FLOAT_EQ(best[0], 2.f);
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EXPECT_EQ(next[0], 1);
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}
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TEST(DijkstraTest, GoalUnreachableNoInfiniteLoop)
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{
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// Two disconnected components: {0, 1} and {2}. Goal = 2, so 0 and 1 must end
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// up unreachable and the algorithm must not loop.
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constexpr int N = 3;
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float cost[N * N];
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makeMatrix<N>(cost, {
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{0, 1, 1.f},
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{1, 0, 1.f},
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});
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float best[N];
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int next[N];
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bool vis[N];
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ASSERT_TRUE(dijkstra::solveBackward(N, 2, cost, best, next, vis));
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EXPECT_FLOAT_EQ(best[2], 0.f);
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EXPECT_FALSE(best[0] < dijkstra::kUnreachable);
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EXPECT_FALSE(best[1] < dijkstra::kUnreachable);
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EXPECT_EQ(next[0], -1);
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EXPECT_EQ(next[1], -1);
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}
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TEST(DijkstraTest, NaNTreatedAsMissingEdge)
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{
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constexpr int N = 3;
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float cost[N * N];
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makeMatrix<N>(cost, {
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{0, 1, 1.f},
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{1, 2, 1.f},
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{0, 2, NAN}, // NaN must be treated like INFINITY, not as a 0 / negative edge
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});
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float best[N];
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int next[N];
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bool vis[N];
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ASSERT_TRUE(dijkstra::solveBackward(N, 2, cost, best, next, vis));
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EXPECT_FLOAT_EQ(best[0], 2.f);
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EXPECT_EQ(next[0], 1);
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}
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TEST(DijkstraTest, RejectsInvalidInputs)
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{
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constexpr int N = 2;
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float cost[N * N] = { INFINITY, 1.f, 1.f, INFINITY };
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float best[N];
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int next[N];
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bool vis[N];
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EXPECT_FALSE(dijkstra::solveBackward(0, 0, cost, best, next, vis));
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EXPECT_FALSE(dijkstra::solveBackward(N, -1, cost, best, next, vis));
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EXPECT_FALSE(dijkstra::solveBackward(N, N, cost, best, next, vis));
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EXPECT_FALSE(dijkstra::solveBackward(N, 0, nullptr, best, next, vis));
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EXPECT_FALSE(dijkstra::solveBackward(N, 0, cost, nullptr, next, vis));
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}
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TEST(DijkstraTest, ForwardWalkReachesGoal)
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{
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// 5-node graph: 0 -> 1 -> 2 -> 3 -> 4, plus a long detour 0 -> 4 directly.
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// Solving once with goal = 4, then for any start we should reach 4 by following
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// next_node without re-solving.
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constexpr int N = 5;
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float cost[N * N];
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makeMatrix<N>(cost, {
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{0, 1, 1.f},
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{1, 2, 1.f},
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{2, 3, 1.f},
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{3, 4, 1.f},
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{0, 4, 100.f}, // direct but expensive
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});
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float best[N];
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int next[N];
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bool vis[N];
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ASSERT_TRUE(dijkstra::solveBackward(N, 4, cost, best, next, vis));
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for (int start = 0; start < N - 1; ++start) {
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int u = start;
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int hops = 0;
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while (u != 4 && hops < N) {
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ASSERT_GE(next[u], 0) << "stuck at " << u << " from start " << start;
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u = next[u];
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++hops;
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}
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EXPECT_EQ(u, 4) << "did not reach goal from " << start;
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}
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}
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@@ -0,0 +1,104 @@
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/****************************************************************************
|
||||
*
|
||||
* Copyright (c) 2026 PX4 Development Team. All rights reserved.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
*
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. 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.
|
||||
* 3. Neither the name PX4 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.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
#include "dijkstra.h"
|
||||
|
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namespace dijkstra
|
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{
|
||||
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bool solveBackward(int num_nodes, int goal, const float *cost,
|
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float *best_cost, int *next_node, bool *visited)
|
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{
|
||||
if (num_nodes <= 0 || goal < 0 || goal >= num_nodes
|
||||
|| cost == nullptr || best_cost == nullptr || next_node == nullptr || visited == nullptr) {
|
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return false;
|
||||
}
|
||||
|
||||
for (int i = 0; i < num_nodes; ++i) {
|
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best_cost[i] = kUnreachable;
|
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next_node[i] = -1;
|
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visited[i] = false;
|
||||
}
|
||||
|
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best_cost[goal] = 0.f;
|
||||
|
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// Standard O(N^2) Dijkstra on the reverse graph: pick the unvisited node u with
|
||||
// the smallest current best_cost, then relax every incoming edge v -> u using
|
||||
// cost(v, u). This yields, for each v, the shortest cost from v to goal and the
|
||||
// next hop next_node[v] = u along that path.
|
||||
for (int iter = 0; iter < num_nodes; ++iter) {
|
||||
int u = -1;
|
||||
float min_cost = kUnreachable;
|
||||
|
||||
for (int i = 0; i < num_nodes; ++i) {
|
||||
if (!visited[i] && best_cost[i] < min_cost) {
|
||||
min_cost = best_cost[i];
|
||||
u = i;
|
||||
}
|
||||
}
|
||||
|
||||
if (u < 0) {
|
||||
// No unvisited node is reachable; remaining nodes stay at kUnreachable.
|
||||
break;
|
||||
}
|
||||
|
||||
visited[u] = true;
|
||||
|
||||
const float u_cost = best_cost[u];
|
||||
|
||||
for (int v = 0; v < num_nodes; ++v) {
|
||||
if (visited[v]) {
|
||||
continue;
|
||||
}
|
||||
|
||||
const float edge = cost[v * num_nodes + u];
|
||||
|
||||
// Treat +INFINITY and NaN as missing edges. `edge < kUnreachable` is false for
|
||||
// both because NaN is unordered and INFINITY < INFINITY is false.
|
||||
if (!(edge < kUnreachable)) {
|
||||
continue;
|
||||
}
|
||||
|
||||
const float candidate = u_cost + edge;
|
||||
|
||||
if (candidate < best_cost[v]) {
|
||||
best_cost[v] = candidate;
|
||||
next_node[v] = u;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
} // namespace dijkstra
|
||||
@@ -0,0 +1,89 @@
|
||||
/****************************************************************************
|
||||
*
|
||||
* Copyright (c) 2026 PX4 Development Team. All rights reserved.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
*
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. 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.
|
||||
* 3. Neither the name PX4 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.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
/**
|
||||
* @file dijkstra.h
|
||||
*
|
||||
* Backward single-source Dijkstra over a precomputed asymmetric cost matrix.
|
||||
*
|
||||
* `solveBackward` computes the shortest path from every node to a fixed `goal`
|
||||
* and returns, for each node `i`, the next node to step toward on its shortest
|
||||
* path to the goal. The intended usage is:
|
||||
*
|
||||
* 1. Whenever the graph (cost matrix) or the goal changes, call solveBackward
|
||||
* once to fill the next-hop table.
|
||||
* 2. As long as both stay fixed, querying the path from any new start `s` is
|
||||
* a constant-time table lookup followed by a forward walk:
|
||||
* u = s; while (u != goal) { emit(u); u = next_node[u]; }
|
||||
* No re-planning, no backtracking, no temporary buffers.
|
||||
*
|
||||
* The cost matrix is row-major with `cost[i * num_nodes + j]` giving the cost
|
||||
* of the directed edge i -> j. Costs may be asymmetric. Entries equal to
|
||||
* +INFINITY or NaN are treated as missing edges. Negative costs are not
|
||||
* supported (Dijkstra assumes non-negative edge weights).
|
||||
*/
|
||||
|
||||
#pragma once
|
||||
|
||||
#include <math.h>
|
||||
|
||||
namespace dijkstra
|
||||
{
|
||||
|
||||
/** Sentinel cost for unreachable nodes / missing edges. */
|
||||
static constexpr float kUnreachable = INFINITY;
|
||||
|
||||
/**
|
||||
* Compute backward shortest paths from every node to `goal`.
|
||||
*
|
||||
* @param num_nodes number of nodes; cost is num_nodes x num_nodes row-major.
|
||||
* @param goal target node index in [0, num_nodes).
|
||||
* @param cost row-major N*N matrix; cost[i*num_nodes + j] is the cost of
|
||||
* the directed edge i -> j, or +INFINITY / NaN if there is
|
||||
* no edge. The diagonal is ignored.
|
||||
* @param best_cost out, length num_nodes: best_cost[i] = shortest cost from i
|
||||
* to goal, or kUnreachable. best_cost[goal] = 0.
|
||||
* @param next_node out, length num_nodes: next_node[i] = the node to step to
|
||||
* from i on the shortest path to goal, or -1 if i == goal or
|
||||
* i has no path to goal.
|
||||
* @param visited scratch buffer, length num_nodes; contents on return are
|
||||
* not meaningful.
|
||||
*
|
||||
* @return true if inputs are valid (non-null, num_nodes > 0, goal in range);
|
||||
* false otherwise. A `true` return does not imply that goal is
|
||||
* reachable from any particular node — check best_cost[i] for that.
|
||||
*/
|
||||
bool solveBackward(int num_nodes, int goal, const float *cost,
|
||||
float *best_cost, int *next_node, bool *visited);
|
||||
|
||||
} // namespace dijkstra
|
||||
Reference in New Issue
Block a user