sparr wrote:

This patch fixes the style issue of ">>" vs " >> "

Attachments

• station_competition_fix_0002.patch (0.58 KiB)

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment7613

sparr wrote:

In OpenTTD two competing stations with ratings of 82% result in 71% of the goods from the industry being transported. In TTD (for Windows), two competing stations with ratings of 80% result in 79% of the goods from the industry being transported. I think this illustrates a disconnect between the design and implementation.

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment7614

Rubidium wrote:

With your the patch applied the combined 'rating' would become 90%.
Given 'amount' = 255, station rating = 80% -> 204.
t = (204 * (255 + 1)) / (204 + (204 / 2)) = 170
station 1 moves: 170 * 204 / 256 + 1 = 136
amount becomes 119
station 2 moves: 119 * 204 / 256 + 1 = 95
total moved: 136 + 95 = 231 -> 231/255 = 90% moved

So your patch does not behave like TTD.

Now for the 'fun' part with your patch:
Given 'amount' = 255, station rating = 25% -> 64.
t = (64 * (255 + 1)) / (64 + (64 / 2)) = 170
station 1 moves: 170 * 64 / 256 + 1 = 43
amount becomes 212
station 2 moves: 212 * 64 / 256 + 1 = 54
total moved: 43 + 54 = 97 -> 97/255 = 38% moved
Hmm, so the second station does get more than the first station. Where's the penalty gone? This happens with all ratings < 50%! So your patch does not give a penalty all the time, i.e. it's comment is at least wrong.

Given 'amount' 255, station ratings 25% and 24% -> 64 and 61
t = (64 * (255 + 1)) / (64 + (61 / 2)) = 174
station 1 moves: 174 * 64 / 256 + 1 = 44
amount becomes 211
station 2 moves: 211 * 61 / 256 + 1 = 51
total moved: 44 + 51 = 95 -> 95/255 = 37% moved
This is even more interesting. Here the second station gets more cargo than the first station even though the first station has a higher rating. So the patch actually breaks the 'best station gets most cargo' behaviour!

As you can see at the 'total moved' lines the industry rating gets higher in all cases (except a 100% station rating, i.e. rating 255).

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment7627

sparr wrote:

Your analysis breaks at "amount becomes 119". The relevant line says "amount -= t;", not "amount -= moved;".

Given 'amount' = 255, station rating = 80% -> 204.
t = (204 * (255 + 1)) / (204 + (204 / 2)) = 170
station 1 moves: 170 * 204 / 256 + 1 = 136
amount becomes 85
station 2 moves: 85 * 204 / 256 + 1 = 68
total moved: 136 + 68 = 204 -> 204/255 = 80% moved

The correction applies to your other examples as well.

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment7628

frosch wrote:

Attached is a TTD (Dos) savegame, you can load both in TTD and OTTD next to each other and unpause. The ratings and transportation percentage match very well. Both can result in 66% transported while both stations have 78% rating (around march 1951).

So please proof your observation.

Attachments

• trt02.sv1 (181.42 KiB)

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment7629

Rubidium wrote:

sparr, you're right those numbers are wrong.

Although now the 'real' question becomes. Should we send 'on average' more cargo through than the maximum cargo rating would do in a 1 station case?

With your algorithm/change it would consistently overestimate; for any 'amount'.

With trunk's algorithm it would underestimate for the higher 'amounts' but overestimate with lower 'amounts' (<5). Given that the function is called more more often with lower 'amounts' (amount 1: 25%, amount 2: 14%, amount 3: 9%, amount 4: 7%), so they cancel eachother out over time. Those percentages come from an # openttdcoop savegame over ~1 million calls to the MoveGoodsToStation function).

With your algorithm given 'amount' 2 and equal ratings, station 2 would get occasionally some cargo from rating 209 and lower, with trunk it has a chance from rating 255 and lower. In both cases it's a 50% change, i.e. with even ratings station 2 gets some cargo.

Attached is a spreadsheet to experiment a bit with the numbers. It has an idea for improvement, but I'm not very satisfied with it.

Anyhow... changing this algorithm might increase the amount of generated cargo/passengers and people are already complaining about that. Not quite sure what the best approach is going to be.

Attachments

• crazy_move_goods.ods (218.84 KiB)

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment7631

Rubidium wrote:

But the problem with the cargo distribution to stations is bigger than just this rating issue, so the simple 'fix' doesn't really fix it in all cases. It actually seems to make it worse in some.

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment7633

Rubidium wrote:

As shown before this is hardly a trivial change, so it needs quite some testing after it's fixed, i.e. not a candidate for the 1.0.x bugfix releases.

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment8087

Rubidium wrote:

Could you please test the attached patch, or the binaries at http://devs.openttd.org/~rubidium/fs3637/

I think it needs some real world multiplayer competition game to really test this, right?

Attachments

• fs3637.diff (4.56 KiB)

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment8798

atorkhov wrote:

Me and V453000 did a test on server that was setup by dihedral. We were picking up of a same industries, station rating was almost the same (+/- 5%) and we got almost equal distribution of cargo in average by graph. So, it this case it works fine, I think.

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment8824

atorkhov wrote:

With this patch it does not give cargo for any station that have rating beyond 3rd. I think this is wrong behaviour if the goal is to have competition.
Also, this means that I can build 2 stations for an industry and nobody else will be able to get cargo from it.

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment8825

Rubidium wrote:

Previously the third and lower stations didn't get any cargo at all either, and the second did get roughly 75% less cargo than it does now. Sharing the cargo amongst more stations is beyond the scope of this bug; there is another issue about that though.

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637#comment8826

Rubidium closed the ticket.

Reason for closing: Fixed

In r20857

This comment was imported from FlySpray: https://bugs.openttd.org/task/3637