New inflation layer

configuration/packages/configuring-costmaps.rst

@@ -378,6 +378,7 @@ Plugin Parameters
 
   costmap-plugins/static.rst
   costmap-plugins/inflation.rst
+  costmap-plugins/inflation_legacy.rst
   costmap-plugins/obstacle.rst
   costmap-plugins/voxel.rst
   costmap-plugins/range.rst

configuration/packages/costmap-plugins/inflation.rst

@@ -64,3 +64,45 @@ This layer places an exponential decay functions around obstacles to increase co
 
   Description
     Whether to inflate unknown cells.
+
+
+:``<inflation layer>``.num_threads:
+
+  ==== =======
+  Type Default
+  ---- -------
+  int  -1
+  ==== =======
+
+  Description
+    Number of threads to use for inflation computation when OpenMP is enabled.
+    Set to ``-1`` for auto-detection (uses half of available CPU cores), or specify a positive integer for explicit thread count.
+    Ignored if OpenMP support is not available.
+
+Building with OpenMP
+--------------------
+
+OpenMP parallelization is disabled by default. To enable it, pass the ``ENABLE_OPENMP`` CMake option when building:
+
+.. code-block:: bash
+
+    # Build with OpenMP enabled
+    colcon build --packages-select nav2_costmap_2d --cmake-args -DENABLE_OPENMP=ON
+
+    # Build with OpenMP disabled (default)
+    colcon build --packages-select nav2_costmap_2d --cmake-args -DENABLE_OPENMP=OFF
+
+Performance Benchmarks
+----------------------
+
+**Test Configuration:** 2000×2000 Grid (4M cells, 50% occupancy, 2m inflation radius)
+
+**Robot Hardware:** 16 cores × 5000 MHz
+
++---------------------+----------+------------------+---------------------------+
+| Configuration       | Time     | Throughput       | vs Legacy Inflation Layer |
++=====================+==========+==================+===========================+
+| OpenMP disabled     | 48.9 ms  | 81.8 M cells/s   | 2.1× faster               |
++---------------------+----------+------------------+---------------------------+
+| OpenMP enabled      | 9.11 ms  | 468.9 M cells/s  | 11.5× faster              |
++---------------------+----------+------------------+---------------------------+

configuration/packages/costmap-plugins/inflation_legacy.rst

@@ -0,0 +1,70 @@
+.. inflation:
+
+Legacy Inflation Layer Parameters
+=================================
+
+.. warning::
+
+   This layer has been deprecated in favor of the refactored :doc:`Inflation Layer <inflation>`, which offers significantly improved performance (up to 11.5× faster with OpenMP enabled). Consider migrating to the new implementation.
+
+This layer places an exponential decay functions around obstacles to increase cost to traverse near collision. It also places a lethal cost around obstacles within the robot's fully inscribed radius - even if a robot is non-circular for optimized first-order collision checking.
+
+``<inflation layer>`` is the corresponding plugin name selected for this type.
+
+
+:``<inflation layer>``.enabled:
+
+  ==== =======
+  Type Default
+  ---- -------
+  bool True
+  ==== =======
+
+  Description
+    Whether it is enabled.
+
+:``<inflation layer>``.inflation_radius:
+
+  ====== =======
+  Type   Default
+  ------ -------
+  double 0.55
+  ====== =======
+
+  Description
+    Radius to inflate costmap around lethal obstacles.
+
+:``<inflation layer>``.cost_scaling_factor:
+
+  ====== =======
+  Type   Default
+  ------ -------
+  double 10.0
+  ====== =======
+
+  Description
+    Exponential decay factor across inflation radius.
+
+
+:``<inflation layer>``.inflate_unknown:
+
+  ==== =======
+  Type Default
+  ---- -------
+  bool False
+  ==== =======
+
+  Description
+    Whether to inflate unknown cells as if lethal.
+
+
+:``<inflation layer>``.inflate_around_unknown:
+
+  ==== =======
+  Type Default
+  ---- -------
+  bool False
+  ==== =======
+
+  Description
+    Whether to inflate unknown cells.

migration/Kilted.rst

@@ -796,3 +796,11 @@ New default_cancel_timeout parameter in bt_navigator
 In `PR 5895 <https://github.com/ros-navigation/navigation2/pull/5895>`_, a new `default_cancel_timeout` parameter was introduced to address timeout issues during action cancellation, such as ``Failed to get result for follow_path in node halt!``.
 
 The default value is set to `50` milliseconds, and should be adjusted based on the planning time and overall system performance.
+
+Refactored Inflation layer powered by OpenMP
+--------------------------------------------
+
+`PR #5933 <https://github.com/ros-navigation/navigation2/pull/5933>`_ refactors the Inflation layer to leverage OpenMP for parallel processing, significantly improving performance in large maps.
+
+The new implementation replaces the previous queue-based cell iteration with a Felzenszwalb-Huttenlocher distance transform algorithm.
+When OpenMP is not available at compile time, the layer falls back to single-threaded operation.

plugins/index.rst

@@ -51,7 +51,12 @@ Costmap Layers
 |                                |                        | occupancy information into       |
 |                                |                        | costmap                          |
 +--------------------------------+------------------------+----------------------------------+
-| `Inflation Layer`_             | Eitan Marder-Eppstein  | Inflates lethal obstacles in     |
+| `Inflation Layer`       _      | Tony Najjar            | Inflates lethal obstacles in     |
+|                                |                        | costmap with exponential decay   |
+|                                |                        | (with the option to use OpenMP   |
+|                                |                        | for parallelization) ____________|
++--------------------------------+------------------------+----------------------------------+
+| `Legacy Inflation Layer`_      | Eitan Marder-Eppstein  | Inflates lethal obstacles in     |
 |                                |                        | costmap with exponential decay   |
 +--------------------------------+------------------------+----------------------------------+
 |  `Obstacle Layer`_             | Eitan Marder-Eppstein  | Maintains persistent 2D costmap  |
@@ -81,6 +86,7 @@ Costmap Layers
 .. _Static Layer: https://github.com/ros-navigation/navigation2/tree/main/nav2_costmap_2d/plugins/static_layer.cpp
 .. _Range Layer: https://github.com/ros-navigation/navigation2/tree/main/nav2_costmap_2d/plugins/range_sensor_layer.cpp
 .. _Inflation Layer: https://github.com/ros-navigation/navigation2/tree/main/nav2_costmap_2d/plugins/inflation_layer.cpp
+.. _Legacy Inflation Layer: https://github.com/ros-navigation/navigation2/tree/main/nav2_costmap_2d/plugins/legacy_inflation_layer.cpp
 .. _Obstacle Layer: https://github.com/ros-navigation/navigation2/tree/main/nav2_costmap_2d/plugins/obstacle_layer.cpp
 .. _Spatio-Temporal Voxel Layer: https://github.com/SteveMacenski/spatio_temporal_voxel_layer/
 .. _Non-Persistent Voxel Layer: https://github.com/SteveMacenski/nonpersistent_voxel_layer