Nav2 AMCL: add random_seed param for deterministic replay; remove hidden time seeding in PF by StanByriukov02 · Pull Request #5856 · ros-navigation/navigation2

StanByriukov02 · 2026-01-09T20:04:08Z

Today nav2_amcl seeds RNG internally from wall-clock time (srand48(time(NULL))) and uses drand48() during resampling / pose sampling. That makes AMCL runs non-replayable even with identical inputs.

This PR makes randomness explicit:

Adds random_seed parameter (default -1 keeps legacy behavior, >=0 enables deterministic replay).
Moves seeding to the node layer.
Adds pf_seed() API and removes hidden seeding from pf_alloc().

Owner-routing ask: who owns AMCL replayability / regression reproducibility for Nav2? If there’s an existing preferred pattern (e.g., use rclcpp random / parameter naming), I’ll align.

codecov · 2026-01-09T20:48:16Z

Codecov Report

✅ All modified and coverable lines are covered by tests.

Files with missing lines	Coverage Δ
nav2_amcl/src/amcl_node.cpp	`86.63% <100.00%> (+0.07%)`	⬆️
nav2_amcl/src/pf/pf.c	`91.62% <ø> (-0.04%)`	⬇️

... and 27 files with indirect coverage changes

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

nav2_amcl/test/test_random_seed_parameter.cpp

SteveMacenski · 2026-01-09T21:40:52Z

nav2_amcl/src/amcl_node.cpp

+  // Deterministic replay knob:
+  // - set random_seed >= 0 to make AMCL replayable under dispute (same inputs -> same outputs),
+  // - keep default (-1) to preserve time-seeded behavior.
+  random_seed_ = this->declare_or_get_parameter("random_seed", -1);


Please add this to the configuration guide page for AMCL at docs.nav2.org

Done — added random_seed (default: -1) to nav2_bringup/params/nav2_params.yaml so it shows up in the canonical config surface.

This needs to be updated on docs.nav2.org: https://docs.nav2.org/configuration/packages/configuring-amcl.html

nav2_amcl/include/nav2_amcl/amcl_node.hpp

nav2_amcl/src/amcl_node.cpp

Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

nav2_bringup/params/nav2_params.yaml

SteveMacenski · 2026-01-12T21:27:52Z

nav2_amcl/src/amcl_node.cpp

+  // Deterministic replay knob:
+  // - set random_seed >= 0 to make AMCL replayable under dispute (same inputs -> same outputs),
+  // - keep default (-1) to preserve time-seeded behavior.
+  random_seed_ = this->declare_or_get_parameter("random_seed", -1);


This needs to be updated on docs.nav2.org: https://docs.nav2.org/configuration/packages/configuring-amcl.html

SteveMacenski · 2026-01-12T21:28:50Z

Small details and then happy to merge!

Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

StanByriukov02 · 2026-01-13T11:05:24Z

Done.

Can we merge?

SteveMacenski · 2026-01-13T17:18:46Z

Please see https://github.com/ros-navigation/navigation2/pull/5856/files#r2683965698 -- we still need the docs PR opened to add this to the configuration guide

Otherwise, the code changes are approved!

StanByriukov02 · 2026-01-13T22:01:44Z

Docs PR opened in docs.nav2.org to document random_seed and update the example YAML: ros-navigation/docs.nav2.org#848

StanByriukov02 · 2026-01-14T07:23:53Z

Great - this will be useful.

Quick favor: could you reply confirming (in plain text) that my AMCL random_seed determinism/replayability changes were reviewed and merged?

Refs:

ros-navigation/navigation2 PR Nav2 AMCL: add random_seed param for deterministic replay; remove hidden time seeding in PF #5856 (merge commit a17d7d8)
ros-navigation/docs.nav2.org PR Re-enable nav2_costmap_2d warnings #848 (merge commit 49c1a1c842fe0be389fb6bb8dbe67f08775c78cf)

One sentence is enough, with your name + role/affiliation + today’s date. If you’d rather do this over email, tell me the best address and I’ll send the exact text.

Thank you - time sensitive.

SteveMacenski · 2026-01-14T15:23:38Z

I'm sorry - what is this regarding?

StanByriukov02 · 2026-01-14T16:43:05Z

This is for a time-sensitive attorney/immigration evidence packet.

I need a single plain-text confirmation from you that you reviewed and merged my AMCL random_seed change.

One sentence like this is enough:

“I reviewed and merged ros-navigation/navigation2 PR #5856 (AMCL random_seed). — Steve Macenski, Nav2 maintainer, YYYY-MM-DD”

This will be enough if it is not difficult.

…den time seeding in PF (ros-navigation#5856) * nav2_amcl: add random_seed for deterministic replay Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: avoid long in pf_seed signature Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: avoid long cast when seeding RNG Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: add gtest to cover random_seed deterministic branch Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: fix whitespace for pre-commit Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: address review feedback for random_seed Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: remove random_seed comments; document parameter Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> --------- Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> Co-authored-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

…den time seeding in PF (ros-navigation#5856) * nav2_amcl: add random_seed for deterministic replay Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: avoid long in pf_seed signature Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: avoid long cast when seeding RNG Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: add gtest to cover random_seed deterministic branch Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: fix whitespace for pre-commit Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: address review feedback for random_seed Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: remove random_seed comments; document parameter Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> --------- Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> Co-authored-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> Signed-off-by: lotusymt <mengtiy5@uci.edu>

…den time seeding in PF (ros-navigation#5856) * nav2_amcl: add random_seed for deterministic replay Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: avoid long in pf_seed signature Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: avoid long cast when seeding RNG Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: add gtest to cover random_seed deterministic branch Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: fix whitespace for pre-commit Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: address review feedback for random_seed Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> * nav2_amcl: remove random_seed comments; document parameter Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> --------- Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com> Co-authored-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

StanByriukov02 added 4 commits January 9, 2026 22:10

nav2_amcl: add random_seed for deterministic replay

5acf824

Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

nav2_amcl: avoid long in pf_seed signature

6a5f65f

Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

nav2_amcl: avoid long cast when seeding RNG

a73816e

Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

nav2_amcl: add gtest to cover random_seed deterministic branch

7508a89

Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

StanByriukov02 force-pushed the amcl-random-seed-replayability branch from c6abf3c to 7508a89 Compare January 9, 2026 21:11

nav2_amcl: fix whitespace for pre-commit

1ab8b9f

Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

SteveMacenski reviewed Jan 9, 2026

View reviewed changes

nav2_amcl: address review feedback for random_seed

bb2f077

Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

SteveMacenski reviewed Jan 12, 2026

View reviewed changes

StanByriukov02 force-pushed the amcl-random-seed-replayability branch from 4992b86 to 9656061 Compare January 13, 2026 10:24

nav2_amcl: remove random_seed comments; document parameter

142ce09

Signed-off-by: StanByriukov02 <StanByriukov02@users.noreply.github.com>

StanByriukov02 force-pushed the amcl-random-seed-replayability branch from 9656061 to 142ce09 Compare January 13, 2026 10:29

SteveMacenski approved these changes Jan 13, 2026

View reviewed changes

StanByriukov02 mentioned this pull request Jan 13, 2026

docs(amcl): document random_seed parameter ros-navigation/docs.nav2.org#848

Merged

SteveMacenski merged commit a17d7d8 into ros-navigation:main Jan 13, 2026
17 checks passed

Conversation

StanByriukov02 commented Jan 9, 2026

Uh oh!

codecov bot commented Jan 9, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codecov Report

Uh oh!

Uh oh!

SteveMacenski Jan 9, 2026

Choose a reason for hiding this comment

Uh oh!

StanByriukov02 Jan 9, 2026

Choose a reason for hiding this comment

Uh oh!

SteveMacenski Jan 12, 2026

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

SteveMacenski Jan 12, 2026

Choose a reason for hiding this comment

Uh oh!

SteveMacenski commented Jan 12, 2026

Uh oh!

StanByriukov02 commented Jan 13, 2026

Uh oh!

SteveMacenski commented Jan 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

StanByriukov02 commented Jan 13, 2026

Uh oh!

Uh oh!

StanByriukov02 commented Jan 14, 2026

Uh oh!

SteveMacenski commented Jan 14, 2026

Uh oh!

StanByriukov02 commented Jan 14, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

codecov bot commented Jan 9, 2026 •

edited

Loading

SteveMacenski commented Jan 13, 2026 •

edited

Loading