It seems to me that certain items only appear in GO HQ when either I don't need them, or I haven't got enough room in my storage to buy them. I have thought this for a while but thought I was probably imagining it so I started making notes of what's on offer and when and I've come to the conclusion that it is true.

And here I thought I was the only one who felt this way! Actually, I don't truly believe that they designed it this way (but it would be possible without being overly complicated, using a simple weighting algorithm). It seems more likely that when the game tells you that you need cheese for a particular shipment, it is also telling many other players the exact same thing, making cheese into a suddenly-rare commodity.[edit 4/12/15]: I've changed my position on this, see newer posts below. If you feel that the answer provided here resolves your concern, please feel free to click accept solution as this may help others with similar issues obtain resolution. XP is greatly appreciated but not required.

@etamni103 wrote: (but it would be possible without being overly complicated, using a simple weighting algorithm). The "simple weighting algorithm" would become far less simple when you have to read the user's mind. How do you know the user is looking for a couch, or merely the lumber needed to build one? How do you know the user is looking for a table that he needs, and not a lock or a dozer part because he's more interested in expanding at the moment than building? Or do you just weight everything you think the user could possibly need? I currently have eight sets of building requirements in my city, with between 3 and 6 item requirements each. A "simple weighting algorithm" would have to weight each of those items, as well as the components used to make them, plus dozer parts and storage parts. That's probably close to everything available in HQ, making the weighting meaningless and the algorithm nothing more than a waste of CPU cycles.I suppose you're right in that it would be possible with a simple weighting algorithm, as long as nowhere in the requirements is it stated that such an algorithm actually also be particularly effective. 🙂In reality, I'm sure nothing is happening. No algorithm, and I'd be willing to bet that the item requirements are equally distributed. It's human nature to try to find patterns where none exist. Earlier I needed three couches to upgrade a building. But I was planning on building them, not buying them. Couches were all over the HQ. So I needed them and there was also plenty of supply. Right now I have absolutely ZERO need for cheese. But I haven't seen a single cheese all morning. Or beef for that matter. Or several other things I'm not looking for. So I don't need them at all, and yet they're still hard to find. There are always a couple of building upgrades that I need to do that require wood, plastic, or metal from the factory. Yet, I can find all of these things easily in HQ because people love to sell the easy stuff. There are plenty of examples where the pattern doesn't hold, but most people aren't paying attention to those times, because they're only noticing when things don't go their way. 🙂Point is, most people can't find what they need right away, and they assume a causal relationship; "I need it and can't find it, therefore it's hard to find because I need it." Those people don't bother to notice that they also can't find things they DON'T need, or that they sometimes CAN find what they DO need. There is no causal relationship, it's a coincidence. Or maybe there's a rogue dev on the team that just wants to watch the world burn, cleverly obfuscating his cheese-hoarding algorithm so that it passes peer review, giggling to himself in the darkness of his corner cubicle.... 😕mileywink:

It 'does' seem that way and, maybe, there's something going on in the background. You never really know for certain.

The evidence suggests very strongly that it is. E.g. Cheese kept showing up for sale tome and again when I logged into GTHQ. I then got a request for cheese in one of my building projects and it hasn't shown up since. Itchy beard.

@jeffk42 wrote:Or maybe there's a rogue dev on the team that just wants to watch the world burn, cleverly obfuscating his cheese-hoarding algorithm so that it passes peer review, giggling to himself in the darkness of his corner cubicle.... 😕mileywink:That was worth one XP all by itself! 😕mileyvery-happy:@jeffk42 wrote:@etamni103 wrote: (but it would be possible without being overly complicated, using a simple weighting algorithm). The "simple weighting algorithm" would become far less simple when you have to read the user's mind. How do you know the user is looking for a couch, or merely the lumber needed to build one? How do you know the user is looking for a table that he needs, and not a lock or a dozer part because he's more interested in expanding at the moment than building? Or do you just weight everything you think the user could possibly need? I currently have eight sets of building requirements in my city, with between 3 and 6 item requirements each. A "simple weighting algorithm" would have to weight each of those items, as well as the components used to make them, plus dozer parts and storage parts. That's probably close to everything available in HQ, making the weighting meaningless and the algorithm nothing more than a waste of CPU cycles.To use a counter-example, would it be possible to make a "simple weighting algorithm" that helps the player find what he/she is looking for? Of course it would be. To keep it simple, let's say that the player has one building needing to be upgraded, and one ship that needs its order fulfilled. The player hasn't built an airport yet. The upgrade needs 8 nails, 3 logs, and 2 meat patties. The ship needs 4 measuring tape, 3 metal, and 2 hamburgers. For each item in the list, the game (or the server) would add +1 to the weight of that item, and +1 to each ingredient in that item. Additionally it would note that the player had not fully expanded the storage or the land, and might add some value to the weight of the expansion items as well. We'd end up with a weighted list that looks something like this: metal +5wood +2plastic +2seeds +1textiles +1animal feed +2nails +1measuring tape +1cooking utensils +1flour bag +1cream +1meat patties +2bread roll +1burgers +1BBQ grill +1storage cameras +10storage locks +10storage bars +10dozer exhaust +10dozer gear +10dozer blade +10Note that I have not given any weight to the quantity of each item needed. Of course, at this point it doesn't look simple any longer, but the game could calculate this faster than a human blinks. The "simple weighting algorithm" would do it's random calculation of what to show in the Global HQ, giving extra chances to the items shown in the list, based on the "weight" assigned the items. Once it selects the item types to show, it would select randomly from among all the advertised sales of those items that hadn't been sold yet, and place them on the shelf. In order to use the process to weight against the items being shown, it would do the same thing, but intead of weighting in extra chances of an item showing up, it would reduce those chances for the same items. Presto, artificial scarcity!Having said all that, I still think the scarcity comes from everybody getting ships and planes that want the same items, around the same time. When that happens, people stop selling those items.[edit 4/12/2015] I've changed my position on this and now believe they are using an algorithm of some kind to weight against what the player needs. Please see my newer posts below. If you feel that the answer provided here resolves your concern, please feel free to click accept solution as this may help others with similar issues obtain resolution. XP is greatly appreciated but not required.

Sneaky algorithm | EA Forums

65 Replies

Anonymous
11 years ago
Approved
@jeffk42 wrote:

Of course, I don't know how they've designed HQ. It could be that when you put something up for sale, a sale request is sent to the server, given an id and maintained in a pool (a huge hash? idk) until someone clicks on HQ, at which point the server sends back an id reference to 24 semi-random sales. That may be over-simplifying it. But the overhead to filter those items for every single HQ click would be significant. Rather than just (for example) grabbing 24 hash keys, you need to get the "type" of every item in the pool, determine the needed percentages based on weights so you don't just always get 24 of your highest weighted item, and then actively seek out that many of each type of item. If the only way to get to a sale is by hash key, this becomes an extremely expensive series of operations. And it would have to be executed on every single HQ click! A database would have more overhead, but would allow filtering on type. You'd still probably need to do multiple queries to ensure a properly weighted result. (apologies to the EA devs for what is probably a gross over-simplification for something that certainly required a lot of effort to implement)

Looking to another source, I took a peek at EA's careers site to see what skills and experience they might be searching for. Unfortunately, it isn't always possible to tell which jobs go with which games, but I did see a number of positions where experience with several different languages and database platforms was requested, so no help there. Other than violating the Ts&Cs of the game, it might be possible to reverse engineer the client app (or packet-sniff the traffic) and gain insight into how the back end works, but it's not worth the effort for a free game! LOL. I'd rather that they just implement a free-market commodities trading system that either has no caps on prices, or caps them very high (say, 999,999 Simoleons), effectively leaving them uncapped. Daniel would not buy unsold items, but the sale could be cancelled and reposted with a different price. (Discussed ad nauseam elsewhere so I won't explain it again here.)
Anonymous
11 years ago
Approved
@BasinCity wrote:
The huge lag in bringing up the exchange is likely evidence that there is such an algorithm in use...

Just sayin'...
No, it's not likely at all.
Anonymous
11 years ago
Approved
@etamni103 wrote:

Looking to another source, I took a peek at EA's careers site to see what skills and experience they might be searching for. Unfortunately, it isn't always possible to tell which jobs go with which games, but I did see a number of positions where experience with several different languages and database platforms was requested, so no help there.

Also, in the 15 years I've been a software engineer, I don't know that I've ever once seen a set of job requirements accurately match the "actual" job requirements, lol. :-)
Anonymous
11 years ago
Approved
I experienced this the other day with light bulbs. Light bulbs are everywhere, easy ish to make and I usually have a few of them.
Yep... I needed one for a key and, despite trying for a LONG time I couldn't find one. "Odd? There's always ligh bulbs!" I made one and, literally after completing the task, the GHQ listed light bulbs again.
Grrrrr.
Anonymous
11 years ago
Approved
As a software developer myself, I'd say that if you found a JD that matches to a T everything you'll be doing to a T within software dev, then run, don't walk away from that offer. That has legacy/dinosaur system or plodding thinkers written all over it. (o:
Anonymous
11 years ago
Approved
@keithroby wrote:
As a software developer myself, I'd say that if you found a JD that matches to a T everything you'll be doing to a T within software dev, then run, don't walk away from that offer. That has legacy/dinosaur system or plodding thinkers written all over it. (o:
No doubt! Again, was just hoping to see if the company was hinting at anything about the back end by posting job requirements that included references to particular platforms. Alas, they have so many games (and so many previous acquisitions) that it is impossible to get that hint from their job announcements!
If this helps resolve your issue, please click accept solution as this may help others with the same issue to find a resolution as well. XP is appreciated but not required.
Anonymous
11 years ago
Approved
@jeffk42
At this point, I am reversing my earlier position: I now believe that they are using some kind of weighting system to somehow decrease the likelihood that needed items will come up in the Global HQ. The method would be similar to the sample weighting system outlined earlier in this thread. I believe that the client app (the game, for non-programmers) is identifying what is needed and then generates a query that weights against that list, and the back end (EA's computer) is then delivering a "random" list that has been calculated per the query's parameters.
The basis for this is testing completed over the past few days. In that testing, I first set it up so that I no longer "needed" storage expansion items. I have enough of these to complete my next upgrade of the storage area, but I haven't done so. As a result of this, I am seeing all three kinds of storage items on many of my trips to the Global HQ. Often, I am seeing two or more of what were previously the most rare items. They still sell fast, so I still see the "sold" indication frequently, but I have been able to purchase more storage bars in the past 48 hours than in the two weeks prior to this.
The next part of the test has been to systematically add residential areas to my city, but only upgrade each one a single time. I then queue up enough of each material needed to upgrade those areas further and sell off all of my supplies of those upgrade material. Once sold off, I check the availability of that material over and over, and found them to be pretty rare. At the exact instant that the crafting of the material is completed, and I collect it, it becomes available in the Global HQ again.
The third part of my test, which is not complete yet, involves creating a situation where every single material is "needed" for something, with the exception of the expansion materials. I don't know if I will get a Global HQ full of expansion materials, or just a random mix of everything, but it will be interesting.
After this testing is done, I am considering doing the following: Make a bunch of a single rare or time-consuming item. Enough to completely fill my Trade Depot. Rename my city to something like: PIZZA 4 SALE or NAILS 4 SALE etc. and then advertise the sale of one metal for max price. When all of the item is sold, I'll change the city name back to its usual name. If this catches on, and others do the same, it could make this a better game for everyone.
If this helps resolve your issue, please click accept solution as this may help others with the same issue to find a resolution as well. XP is appreciated but not required. As a reminder, the opinions expressed in this reply are strictly my own opinion and may not reflect the opinion of EA or any of its employees. I acknowledge that the results described above may be completely coincidental, but I don't think they are.
Anonymous
11 years ago
Approved
Hey, believe what you want. 🙂 Your tests do not convince me though. My own testing has shown me that sometimes items just aren't available for a while, whether I need them or not. I can go days without seeing a single beef, even when no beef or beef-derived item is required in my city.

So maybe not many people were selling beef, combined with the fact that I'm getting a random sampling of 24 items out of hundreds of thousands. There doesn't have to be a conspiracy. But as I said, believe what you want, it doesn't affect me in the slightest. 🙂
Anonymous
11 years ago
Approved
Just let Vu destroy a couple of buildings a few minutes ago. I needed refrigerators, and I had none. Went to HQ, at least one refrigerator was available on 3 out of 5 refreshes. One of those 3 refreshes showed a refrigerator from two separate cities. Next, I needed glass and didn't want to wait to build it. Glass showed up on the first refresh.
Anonymous
11 years ago
Approved
People have questioned why EA would rig the World Trade HQ? The answer is in app purchases.

I spent an hour trying to find two yogurts for my plane. I got down to 90 seconds before it took off and bought 450 SimBucks for $5. Guess what, I found yogurts afterwards. A waiting system does not preclude a player from finding an item because a seller could list an item after you have that seller's marketplace in your 30 second window. The game play is running on a sever, so a weighting system could run effectively; maybe not even effectively. That may be why the delay to load the World Trade HQ. But the incentive is there for EA.

I get that companies need to make a profit. I can't say I would have downloaded the game if it was expensive. But the system needs to be fair. If you want to buy 400 Simbucks to purchase a basketball court, then go for it. But don't rig a "marketplace." In real life, that will get you a jail term; so, from a moral standpoint, a game shouldn't be rigged.

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Sneaky algorithm

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