Smoothing crashing due to indexing error

[hjabbot]

Smoothing is crashing in a mesh with only land masses (no SIC, no currents, just a GRF elevation dataloader). I've plotted the mesh and I can't see anything obvious causing it.

Attached are the vessel mesh file, route config, waypoints used to create the crash, along with the dijkstra route saved out before the crash.
index_issue.zip

Traceback (most recent call last):
  File "/tmp/ipykernel_57641/66007170.py", line 47, in optimise_routes
    build_route_mesh_if_missing(route_config_file, vessel_mesh_json_file, waypoints_file, output_filename)
  File "/tmp/ipykernel_57641/66007170.py", line 23, in build_route_mesh_if_missing
    smoothed_routes = rp.compute_smoothed_routes()
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/habbot/Documents/Work/BAS/repos/sdadt/PolarRoute/polar_route/utils.py", line 238, in wrapper
    res = func(*args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^
  File "/home/habbot/Documents/Work/BAS/repos/sdadt/PolarRoute/polar_route/route_planner/route_planner.py", line 700, in compute_smoothed_routes
    sf.forward()
  File "/home/habbot/Documents/Work/BAS/repos/sdadt/PolarRoute/polar_route/route_planner/crossing_smoothing.py", line 1371, in forward
    if self.previous_vs(edge_a, edge_b, midpoint_prime):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/habbot/Documents/Work/BAS/repos/sdadt/PolarRoute/polar_route/route_planner/crossing_smoothing.py", line 1087, in previous_vs
    edge_b_start_index = edge_b.start['id']
                         ~~~~~~~~~~~~^^^^^^
TypeError: 'NoneType' object is not subscriptable

[davidwyld]

Also getting this error, with polar-route 1.0.0 (both python interface and CLI) when waypoint splitting is on, using an 'empty' open water mesh from the basic example (https://colab.research.google.com/drive/1N1mxOy2oX7bEGtPy7Ztshrs4Fs_7lBpV?usp=sharing#scrollTo=i-PJy6KMiLk9)

Route config

{
    "objective_function": "traveltime",
    "path_variables": [
        "fuel",
        "traveltime"
    ],
    "vector_names": [
        "uC",
        "vC"
    ],
    "zero_currents": false,
    "variable_speed": true,
    "time_unit": "days",
    "early_stopping_criterion": true,
    "save_dijkstra_graphs": true,
    "waypoint_splitting": true,
    "smoothing_merge_separation": 1e-3,
    "smoothing_converged_sep": 1e-3,
    "smooth_path": {
        "max_iteration_number": 1000,
        "minimum_difference": 0.0005
    }
}

The new bits of the config that result in this behaviour are:

    "waypoint_splitting": true,
    "smoothing_merge_separation": 1e-3,
    "smoothing_converged_sep": 1e-3,

Output and stack trace:

❯ optimise_routes traveltime.config.json open_water.vessel.json waypoints_example.csv -o open_water.route.json
[24-10-24 12:26:07 :INFO    ] - optimise_routes 1.0.0
[24-10-24 12:26:07 :INFO    ] - Initialising Route Planner
[24-10-24 12:26:07 :INFO    ] - Calculating Dijkstra routes
[24-10-24 12:26:07 :INFO    ] -  Splitting around waypoints !
[24-10-24 12:26:07 :INFO    ] - ============= Dijkstra Route Creation ============
[24-10-24 12:26:07 :INFO    ] -  - Objective = traveltime
[24-10-24 12:26:07 :INFO    ] - --- Processing Source Waypoint = Start
[24-10-24 12:26:07 :INFO    ] - Destination waypoint: End
[24-10-24 12:26:08 :INFO    ] - Dijkstra routing complete...
[24-10-24 12:26:08 :INFO    ] - Timed call to compute_routes took 0.813959 seconds
[24-10-24 12:26:08 :INFO    ] - Calculating smoothed routes
[24-10-24 12:26:08 :INFO    ] - ========= Determining Smoothed Routes ===========
[24-10-24 12:26:08 :INFO    ] - --- Smoothing Route - Start to End
Traceback (most recent call last):
  File ".../bin/optimise_routes", line 8, in <module>
    sys.exit(optimise_routes_cli())
             ^^^^^^^^^^^^^^^^^^^^^
  File ".../polar_route/utils.py", line 238, in wrapper
    res = func(*args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^
  File ".../polar_route/cli.py", line 202, in optimise_routes_cli
    smoothed_routes = rp.compute_smoothed_routes()
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ".../polar_route/utils.py", line 238, in wrapper
    res = func(*args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^
  File ".../polar_route/route_planner/route_planner.py", line 700, in compute_smoothed_routes
    sf.forward()
  File ".../polar_route/route_planner/crossing_smoothing.py", line 1327, in forward
    if self.previous_diagonals(edge_a, edge_b, firstpoint, lastpoint):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ".../polar_route/route_planner/crossing_smoothing.py", line 1176, in previous_diagonals
    edge_b_start_index = edge_b.start['id']
                         ~~~~~~~~~~~~^^^^^^
TypeError: 'NoneType' object is not subscriptable

[Ulvetanna]

Thanks @davidwilby for the info. Will look into the issue first thing tomorrow !

[davidwyld]

To add to this, if it's helpful, I've run this with the 'real data example' from the docs and get the same bug with waypoint_splitting switched on, and not when it's off.

[Ulvetanna]

Thanks David this has been really useful. As you say I think it's in the splitting around waypoints, currently correcting this in the work, will keep you updated when fixed