slam_toolbox:
  ros__parameters:

    use_sim_time: true

    # ── Solver ──────────────────────────────────────────────────────────────
    solver_plugin: solver_plugins::CeresSolver
    ceres_linear_solver: SPARSE_NORMAL_CHOLESKY
    ceres_preconditioner: SCHUR_JACOBI
    ceres_trust_strategy: LEVENBERG_MARQUARDT
    ceres_dogleg_type: TRADITIONAL_DOGLEG
    ceres_loss_function: None

    # ── Frames ──────────────────────────────────────────────────────────────
    odom_frame: odom
    map_frame: map
    base_frame: base_footprint
    scan_topic: /scan

    # ── Mode ────────────────────────────────────────────────────────────────
    # mapping      — build a new map; publishes /map and /map_metadata
    # localization — localise in a previously-saved map (load with map_server)
    # lifelong     — continuous mapping with loop closure; memory-intensive
    mode: mapping

    # ── Map parameters ──────────────────────────────────────────────────────
    resolution: 0.05          # metres per pixel — 5 cm is good for indoor navigation
    max_laser_range: 12.0     # m — matches RPLIDAR A1 spec; trim to actual room size
    map_update_interval: 5.0  # seconds between map publishes

    # ── Timing / TF ─────────────────────────────────────────────────────────
    transform_publish_period: 0.02   # seconds (50 Hz) — map → odom TF publish rate
    transform_timeout: 0.2           # seconds — how long to wait for a TF lookup
    tf_buffer_duration: 30.0         # seconds — TF history kept in memory
    throttle_scans: 1                # process every Nth scan (1 = all)
    minimum_time_interval: 0.5       # seconds — minimum gap between processed scans

    # ── Scan matching ────────────────────────────────────────────────────────
    use_scan_matching: true
    use_scan_barycenter: true

    # How far the robot must move/turn before adding a new node to the graph
    minimum_travel_distance: 0.5    # m
    minimum_travel_heading: 0.5     # rad (~29°)

    # Scan buffer — larger = more context for loop closure but more memory
    scan_buffer_size: 10
    scan_buffer_maximum_scan_distance: 10.0   # m

    # Matching quality thresholds
    link_match_minimum_response_fine: 0.1
    distance_variance_penalty: 0.5
    angle_variance_penalty: 1.0

    # Angular search parameters
    fine_search_angle_offset: 0.00349     # rad (~0.2°)
    coarse_search_angle_offset: 0.349     # rad (~20°)
    coarse_angle_resolution: 0.0349       # rad (~2°)
    minimum_angle_penalty: 0.9
    minimum_distance_penalty: 0.5
    use_response_expansion: true

    debug_logging: false
    stack_size_to_use: 40000000    # bytes — increase if you see stack overflows