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YAPF and Road Depots #6410

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DorpsGek opened this issue Jan 7, 2016 · 3 comments
Closed

YAPF and Road Depots #6410

DorpsGek opened this issue Jan 7, 2016 · 3 comments
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flyspray This issue is imported from FlySpray (https://bugs.openttd.org/)

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@DorpsGek
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DorpsGek commented Jan 7, 2016

juanjo opened the ticket and wrote:

See topic: http://www.tt-forums.net/viewtopic.php?f=31&t=73100

It seems that this line in yapf_road.cpp:
if (max_distance > 0 && n->m_cost > max_distance * YAPF_TILE_LENGTH) return false;
causes the problem.

m_cost -> cost of the best path (penalty length, not tile length)
max_distance -> usually 2000. It is also penalty length (2000 with penalty is about 20 tiles)
YAPF_TILE_LENGTH = 100

With r27488, if a vehicle needs servicing and it finds a depot at a distance less than 2000 tiles, it will go there skipping all other orders. Changing it to:
if (max_distance > 0 && n->m_cost > max_distance) return false;
will do it if the depot is at a distance less than 20 tiles.

This is the easiest way to solve the bug.

Reported version: trunk
Operating system: All

This issue was imported from FlySpray: https://bugs.openttd.org/task/6410
@DorpsGek
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DorpsGek commented Jan 7, 2016

juanjo wrote:

As I was trying to solve it, I came across that:
- YAPF for rail uses max_distance in a more efficient way: it discards paths longer than max_distance while searching a path. Road and ship do not do it.
For some reason it hasn't been done. Probably, something about efficiency. I could try extending it to road and ship depots if other developers consider it appropriate. If that could be done, I could try with ships finding depots in a better way (#5713 - Boats sent to impossible depots).

- FindDepot in YAPF calculates the cost of the best path, but doesn't return it. If a depot is found, it returns a cost of max_distance/2.
I think that returning a FindDepotData object (tile, cost and reversed) makes the code easier to read. Maybe returning a bool is faster, but I don't know if that is really necessary. The attached patch is for changing this, that could also be changed for YAPF rail.

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This comment was imported from FlySpray: https://bugs.openttd.org/task/6410#comment14108

@DorpsGek
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frosch wrote:

Yes, adding "discarding long paths" to road- and ship pathfinder would be nice.
I referenced your comment in #5713.

This comment was imported from FlySpray: https://bugs.openttd.org/task/6410#comment14199

@DorpsGek
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frosch closed the ticket.

Reason for closing: Fixed

in r27586. Thanks for the patch!

This comment was imported from FlySpray: https://bugs.openttd.org/task/6410

@DorpsGek DorpsGek added Core flyspray This issue is imported from FlySpray (https://bugs.openttd.org/) labels Apr 7, 2018
@SamuXarick SamuXarick mentioned this issue Oct 2, 2018
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@J0anJosep J0anJosep mentioned this issue Jan 4, 2019
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