Edit: This article is based on an earlier vanilla version, and is probably out-of-date considering much has changed in Warlords and BtS since then.


There seems to be a lot of confusion about great people, how they are generated and the odds involved, so I thought I'd try to explain that a bit.



1. Generating Great People

Great people are generated by accumulating great people points (GPPs) in your cities. Every city has its own counter that keeps track of how many GPPs have been produced in that city already, which can be seen in the lower right corner of the city screen. Once a city has reached a specific threshold, a great person will be generated, and the GPP counter of that city will be reset to zero. This threshold is a civ-wide one, and will increase each time a great person is born so that the next one will be harder to get.

For normal game speed, you need 100 GPPs in one of your cities to generate your first great person. From then on, every great person thereafter will cost you an additional 100 GPPs until 1000, then the threshold will be increased by 200 for every great person, making it even harder.

So you need 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, then 1200, 1400, 1600, 1800, 2000, 2200, ... GPPs to generate a new great person.

For Epic game speed, you need 150% of the required GPPs, so it's 150, 300, 450, 600, ...

For Quick game speed, you need only 67% of the required GPPs, so it's 67, 134, 201, ...

Note again that the threshold is civ-wide and the same for all cities, while the GPP counter is individual for each city. For example, you have city A with 80 GPPs and +2 GPPs per turn, and another city B at 99 GPPs and +3 GPPs per turn. So city B will reach the threshold of 100 GPPs next turn. This will produce your first great person, and sets the GPP counter of city B back to 2 (2 excess GPPs are carried over). Additionally, the new threshold for producing a great person is set to 200, so city A, now at 82 GPPs +2 GPPs per turn, will need much longer than before to produce a great person!

For the question whether it's better to concentrate all your GPP production in one city, or spread it over multiple cities, see an article by Vol here (http://forums.civfanatics.com/showthread.php?t=142704).


Note that you will also receive specific great persons if you are the first to discover certain techs (Music, Economics, Physics, ...). This does not effect the threshold for your GPP production in any way. The same is true for great people generated by other civs: They won't effect your threshold either.



2. Sources for GPPs

Normally, a city won't produce any GPPs on its own. There are two sources to produce GPPs, specialists and wonders.

Specialists produce +3 GPPs per turn, except the citizen specialist which will produce none. Great wonders generally produce +2 GPPs per turn, and small wonders +1 GPP per turn. Once a wonder becomes obsolete, it will no longer produce any GPPs.

These GPPs per turn can be further boosted by "+x% birth rate" enhancers. The most obvious one is if you play a philosophical leader, which provides +100% birth rate for all cities. Then there's the Pacifism civic that comes with Philosophy, which adds +100% birth rate for all cities as well. Finally, there are some wonders that provide a similar bonus, like the Parthenon (+50% birth rate for all cities) and the National Epic (+100% birth rate for the city it was built in only). Note that these boni are additive, so if you are a Philosophical leader, have adopted Pacifism and have the Parthenon, you will get +250% GPP production in all cities.



3. Odds to Get a Specific Type of Great Person

There are five types of great persons: Engineers, merchants, scientists, prophets, and artists. The odds of which type of great person will be generated once one of your cities has produced enough GPPs, depends on which types of sources contributed to the GPP pool of that city. The odds can be displayed by mousing over the GPP bar in the lower right corner of the city screen.

Each type of specialist counts as one source for the respective great person type, and each wonder has noted in its description which type of source it is. For example, the Great Library counts as a source for great scientists, while the Parthenon counts as a source for great artists.

If you have produced only one type of GPPs in your city once it has reached the threshold, then you are guaranteed to get a great person of that type. For example, if your city has the Parthenon (source for great artists) and you had hired an artist specialist to increase GPP production, you will be guaranteed to get a great artist.

If you have different types of GPP sources, it gets a little more complicated. For each turn, the game notes what types of sources had produced GPPs in the city (regardless of how many GPPs each source had contributed!). This determines the odds of which type of great person would be produced for that turn. The overall odds are the average values of all the turns since the last great person was generated in that city.


Note that difference: The number of GPPs will determine when a great person will be generated, and the number of sources will determine what type it will be.


Examples:

* You have the Parthenon (great artist source) and a priest specialist (great prophet source) in the city the whole time. Your chances will be 50% to get a great artist and 50% to get a great prophet. Note that it's irrelevant that the Parthenon produced only 2 GPPs while the priest produced 3 GPPs per turn; they both count as one source.

* A city has the Great Library (great scientist source), an engineer, and an artist specialist, plus the two free scientist specialists from the Great Library. So you have 5 sources (one wonder and four specialists). This will give you a 3/5 = 60% chance of getting a great scientist, a 1/5 = 20% chance of getting a great engineer, and a 1/5 = 20% chance of getting a great artist.

* You have the Pyramids (great engineer source) in a city. One turn before the city reaches the threshold to produce a great person, you hire a scientist. What happens? Well, the game remembers that for every turn but the last, the great engineer source had been the only source of GPPs, and that only on the last turn there had been a different source present. So it is a 100% chance of getting a great engineer during all turns but the last, and a 50%/50% chance for the last turn. Since it averages the odds over all the turns, you will have a 99% chance of getting a great engineer, and a 1% chance of getting a great scientist.

* Assuming normal game speed, no great person generated yet: You hire a priest specialist for 22 turns. Then you fire him, and hire two scientist specialists for 11 turns. Intuitively, one would assume that because you had 22*1=22 sources for a great prophet and 11*2=22 sources for a great scientist, this would give you a 50%/50% chance. But because the game averages over turns, the odds will be 22/33 = 67% for a great prophet and 11/33=33% for a great scientist instead, because you had 22 turns with only great prophet sources and 11 turns with only great scientist sources.
(Thanks to Roland Johansen for suggesting this!)


Once the threshold is reached and a great person is generated, the city "forgets" which types of sources there had been before and starts anew. So if you hire a scientist to produce a great scientist, and after generating that great scientist remove the scientist specialist and hire a priest instead, you will have a 100% chance of getting a great prophet as the next great person, since the city will have forgotten that there had been a great scientist source in the city during the previous cycle.



If you have comments, questions, or found any mistakes, feel free to comment!

-Kylearan

Nice to know, especially the odds of getting a GP. I always wondered why my Prophet cities had so high of a percentage on Engineers or Scientists :lol:.

Req

Excellent post. It is great to summarize a long evolving thread into one post which displays all the conclusions and rules in one place for one topic, such as great people generation. Hopefully we will see more summaries like that!

Very good article, especially the bit about the chances to get a specific type of great person is interesting. But I still have a question about it:

Assume a city starts producing its next great person:
It starts with 3 turns with 1 priest specialist and ends with one turn of 3 engineer specialists. At that moment the great person is born (ok, this city needs some very large percentage bonus to great person production, but it is only a simple example).

According to your article, we would have 3 turns with a 100% great prophet production and 1 turn of 100% great engineer production which results in a 75% chance for a great prophet and a 25% chance for a great engineer.

Intuitively, I would expect the game to produce a great prophet with 50% chance and a great engineer with 50% chance because 3 of the 6 great person sources were priests and 3 of the 6 were engineers. But what you're saying is that it works differently and that the results of the turns of great person production are important. Do I understand this correctly?

For better understanding of your readers, you might want to add such an example.

Thank you for this article. :goodjob:

Hi,

Very good article
Thanks! :)

Assume a city starts producing its next great person:
It starts with 3 turns with 1 priest specialist and ends with one turn of 3 engineer specialists. [...]
According to your article, we would have 3 turns with a 100% great prophet production and 1 turn of 100% great engineer production which results in a 75% chance for a great prophet and a 25% chance for a great engineer.
Yes, that's indeed the case. I've just set up a "real life" test: 22 turns with a priest and 11 turns with two scientists resulted in roughly 67% chance for great prophet and 33% chance for great scientist.

For better understanding of your readers, you might want to add such an example.
I'll add that in tomorrow; thanks for suggesting this!

-Kylearan

Yes, that's indeed the case. I've just set up a "real life" test: 22 turns with a priest and 11 turns with two scientists resulted in roughly 67% chance for great prophet and 33% chance for great scientist.

Wow, thank you for testing this so quickly. It's good to know how this works exactly!:goodjob:

Nice article, I never new the exact formula for odds before. Roland Johansen's example clearly shows that.

Yes, that's indeed the case. I've just set up a "real life" test: 22 turns with a priest and 11 turns with two scientists resulted in roughly 67% chance for great prophet and 33% chance for great scientist.
ARGH! What an annoying bug. Can we be sure these are indeed the actual chances or only the values displayed the turn before the GP is born? Many players have reported that tiny chances for certain GPs too often lead to this GP getting born.

I really wish GPPs were counted individually for each type! All this random stuff is extremely annoying. (Though still much better than Civ3, admittedly ;) )

Hi,

ARGH! What an annoying bug.
I'm not sure this is a bug but a design feature. Averaging the odds over turns or over sources is equally valid, and they had decided to go for turns.

Can we be sure these are indeed the actual chances or only the values displayed the turn before the GP is born?
We can't really be sure about that, but I highly doubt the programmers used different routines for calculating the displayed odds and calculating the odds when actually determining which great person to generate. It's much easier and straightforward to use the same routine for that, so I think the displayed odds are correct.

Many players have reported that tiny chances for certain GPs too often lead to this GP getting born.
I chalk that up to selective attention. If you get the great person who had the greatest odds, you won't notice it. But if you really want the engineer which had a 95% chance of being generated, and got that artist instead, it will grab your attention much more.

I really wish GPPs were counted individually for each type! All this random stuff is extremely annoying.
Maybe, but it also opens up yet another strategical layer - do I really want to mix different types in one city? Or will I risk trying to build a wonder in a city with lower production instead, to keep only one source of GPPs in my high-production city?

I like it. :) YMMV, of course.

-Kylearan

So every turn it adds one point of chance if at least 1 GPP of that type is added?
20 Scientists will add one point of chance while 2 will also.
The number of total points only determines when.

So if you have 33 turns of 2 sci and 22 of 1 pro then a Great scientist will have a 60% while the Prophit will have 40%?
What if you have the Library wonder and a sci specialist versus 2 sci specialist during the 33 turns?

As a more complicated example, what about 1 artist for 10 turns, 1 merchant for 20 turns and 1 scientist for 30?
These of course assume that the required total GPP's are exactly what is added, to make it easy.

Hi,

So every turn it adds one point of chance if at least 1 GPP of that type is added?
20 Scientists will add one point of chance while 2 will also.
For every individual turn, it adds 'one point of chance' for every source of GPPs. So in your example, 20 scientists will add 20 points of chance, and 2 scientists 2 points. But because the odds are averaged over all turns, in the end it will be like your example, because you only had one type of source present each turn.

The number of total points only determines when.
That's correct. #GPPs = when, #sources = what. (Maybe I should edit this into the article)

So if you have 33 turns of 2 sci and 22 of 1 pro then a Great scientist will have a 60% while the Prophit will have 40%?
Correct.

What if you have the Library wonder and a sci specialist versus 2 sci specialist
The Great Library grants you two free specialists which act as GPP sources too, so that's a bit more complicated. ;) But if we ignore this for now, then the odds are the same whether you have a wonder and a specialist, or two specialists.

As a more complicated example, what about 1 artist for 10 turns, 1 merchant for 20 turns and 1 scientist for 30?
10/60=17% great artist, 20/60=33% great merchant, 30/60=50% great scientist.

-Kylearan

So what you're saying is, if we want to be sure of getting at least SOME of our individualized great people, we've got to have cities with roughly equivalent GPP production (so they rotate: as each gets its great person, it falls to the end of the line), each with its own "wonder" emphasis?

And toss the extras in different cities (e.g., all the extra prophet wonders, and the occasional national wonder)? And still expect to get more prophets, because of all the prophet wonders and the multiple sources of priest specialists?

Hmmm... I got some planning to do...

Hi,

So what you're saying is, if we want to be sure of getting at least SOME of our individualized great people, we've got to have cities with roughly equivalent GPP production (so they rotate: as each gets its great person, it falls to the end of the line), each with its own "wonder" emphasis?
Did I say this? :confused:

Anyway, whether it's better to concentrate your GPP production in one city, for the cost of maybe getting a 'wrong' type of great person, or dedicate several cities to different types of great persons for the cost of raw GPP production, is yet another trade-off choice Civ 4 has to offer. :) See also Vol's article on this subject mentioned in my first post.

-Kylearan

Great article! Since number of source is so important in determing type of GP, and great engineer is the most useful one (not many people will object, I guess), it makes a lot of sense to build all the engineer source wonders in a city: pyramid, hanging garden, hagia sophia (its own effect is just so so, but for GE ...), pentagon, ... Any other?

And what about this one:
You've build the pyramids, giving you 2 points towards great engineer.
But it will take 50 turns to get one that way.

After 20 turns, using caste system and running a food deficit you hire 6 specialist merchants, for three turns. You grab the money from the merchant specialists, finish the great person not in 50 but in 23 turns and still have a 92 % chance of getting a great engineer.

Yes Radbad, I will try to built Pyramids more often in order to generate sooner a Great Enginner very usefull in order to rush an important wonder!
LeSphinx

Did I say this? :confused:

Sorry. :) By "so you're saying," I meant, "so your article implies to me."

Is it just me, or are Scientist GPP sorely lacking? I don't have my manual in front of me (at work on coffee break), but I seem to recall only the Great Library (WW) and the Oxford University (nw) give direct scientist GPP, while there are several that let you turn people into scientists.

And I just like spreading the WWs around, since you can't dump all the nw into one city. It helps to specialize a bit: a GP farm (national epic & globe theater, focused on food/growth and some production, and the increased GPP world wonder (?)), a primary military city (heroic epic & west point, focused on production, sited on a coast), a supporting military city (ironworks & red cross, focused on production, sited on a coast), a commerce city (wall street & oxford university, sited on a coast, acting as holy city to one or more religions, focused on commerce), plus one city for each great person, with roughly balanced GPP production (meaning needs the world wonders and enough food for a few specialists).

Anyway, break's over. :)

Sorry. :) By "so you're saying," I meant, "so your article implies to me."

Is it just me, or are Scientist GPP sorely lacking? I don't have my manual in front of me (at work on coffee break), but I seem to recall only the Great Library (WW) and the Oxford University (nw) give direct scientist GPP, while there are several that let you turn people into scientists.

And I just like spreading the WWs around, since you can't dump all the nw into one city. It helps to specialize a bit: a GP farm (national epic & globe theater, focused on food/growth and some production, and the increased GPP world wonder (?)), a primary military city (heroic epic & west point, focused on production, sited on a coast), a supporting military city (ironworks & red cross, focused on production, sited on a coast), a commerce city (wall street & oxford university, sited on a coast, acting as holy city to one or more religions, focused on commerce), plus one city for each great person, with roughly balanced GPP production (meaning needs the world wonders and enough food for a few specialists).

Anyway, break's over. :)

Space Elevator, Red Cross, and Scotland yard also are Great Scientist making wonders (and I think Oxford and the GL are the only ones that give/allow Scientist specialists though)

Sorry. :) By "so you're saying," I meant, "so your article implies to me."

Is it just me, or are Scientist GPP sorely lacking? I don't have my manual in front of me (at work on coffee break), but I seem to recall only the Great Library (WW) and the Oxford University (nw) give direct scientist GPP, while there are several that let you turn people into scientists.

And I just like spreading the WWs around, since you can't dump all the nw into one city. It helps to specialize a bit: a GP farm (national epic & globe theater, focused on food/growth and some production, and the increased GPP world wonder (?)), a primary military city (heroic epic & west point, focused on production, sited on a coast), a supporting military city (ironworks & red cross, focused on production, sited on a coast), a commerce city (wall street & oxford university, sited on a coast, acting as holy city to one or more religions, focused on commerce), plus one city for each great person, with roughly balanced GPP production (meaning needs the world wonders and enough food for a few specialists).

Anyway, break's over. :)

The Red Cross and Scotland Yard also are a Scientist source (you can check out my Buildings File for a complete listing according to type of GPP and other goodies), but since you get them so late, they don't help that much.

Heh, I have similar city ideas.

Req

Space Elevator, Red Cross, and Scotland yard also are Great Scientist making wonders (and I think Oxford and the GL are the only ones that give/allow Scientist specialists though)

Hmmm, oops, looks like I had the Space Elevator mislabeled as Great Engineer :p.

Thanks for the update, Krikkitone!

Req

And what about this one:
You've build the pyramids, giving you 2 points towards great engineer.
But it will take 50 turns to get one that way.

After 20 turns, using caste system and running a food deficit you hire 6 specialist merchants, for three turns. You grab the money from the merchant specialists, finish the great person not in 50 but in 23 turns and still have a 92 % chance of getting a great engineer.

During 20 turns, you have 1 source towards GE. After that, you have 3 turns with 1 GE source and 6 GM sources. The total is 23 GE and 18 GM. So your chances are pretty much even.

I tried a similar experiment:
7 turns of 6 GM (specialists) + 1 GE (pyramid)
and then 4 turns of no specialist.

The final probabilities where 80% GM - 20% GE. It is explained by 7x6 = 42 GM and 7+4 = 11 GE. Whereas if only the type of sources mattered, you would get 7 GM / 11 GE.

The difference between counting in terms of GP points vs GP sources isn't that big a deal because the number of points brought by a source is fairly the same: 3 for a specialist and 2 for a wonder. And that precludes this tactic.

Btw, I also tried the 1 priest during 3 turns and then 3 scientists during 1 turn. I get 50/50. I thought it said it should lead to 75/25 :confused:

I'm not so sure the basic premise of this thread is completely true. I've been able to alter the type of GP I get by changing what I'm researching ie. if I'm researching Philosophy I usually get a Prophet and if I'm researching Engineering I usually get an Engineer though this doesn't always work. In regards to which GP type is best I think that since I try to spread my religion I need a Prophet to build a shrine, I need Engineers to hurry early wonders, I need Scientists to build academies and Merchants get sent to far away cities for LOTS of trade gold. In other words a variety of GPs seems best.

Nice to know, especially the odds of getting a GP. I always wondered why my Prophet cities had so high of a percentage on Engineers or Scientists :lol:.

Req

EXACTLY. I've been looking all over for this answer. I would found 4 religions and NEVER get a great prophet. I thought it was b/c I did not build a prophet-building wonder. But no, even with a prophet wonder, still, whole game, zero prophets. I just had no reason to build priests until now. Awesome article.

A minor hijack of this thread, (sorry). Was wondering about the use of Great People. When I first started playing Civ IV, I always saved them to start golden ages, (left over strategy from Civ III I think). But I think this is not the best use for GP's, especially early in the game. Are super specialists a better use early on because of the cummulative effects over time?

Wrong thread. Try this one, it has everything you want to know :

http://forums.civfanatics.com/showthread.php?t=169059

As first glance this formula for the odds seemed quite weird for me... but, thinking about it, i quite like it. Because it averages odds per turn, it means i dont have to worry if, for a few turns, i use a lot of engineers to speed up a building when i want to get a Great Priest or something.Those engineers will only contribute with 100% * few turns, not 100% * (lots of engs * 3) * few turns. It means it wont mess too much with whatever i want to generate, as long as i use lots of specialists in fewer turns.

Want to get a Great Priest? Then using a single Priest for as long as you can will give you very high odds of getting one, no matter if once in a while you used a lot of Merchants for gold or lots of Engs for hammers. The single Priest may have very lil odds on those turns, but the 100% for the majority of turns will almost guarantee you will get what you want.

Cool :)

PS: Is that correct, by the way? Are there any more consequences on the turn-average system i should be aweare of?

Awesome!
I didn't know about the turn averaging. It has important consequences.

Suppose you have a wonder, an excess of 2 food and want to hire a certain type specialist. If you like the GP it would give, use 1 specialist every turn. If you don´t like the GP it would give (you prefer the one form the wonder) it is better to have no specialist for one turn (accumulating food) and 2 specialists for one turn (starving the city). Even best no specialist for 2 turns and 2 specialists for 1 turn, etc...

Want to get a Great Priest? Then using a single Priest for as long as you can will give you very high odds of getting one, no matter if once in a while you used a lot of Merchants for gold or lots of Engs for hammers. The single Priest may have very lil odds on those turns, but the 100% for the majority of turns will almost guarantee you will get what you want.


Really good, useful point MestreLion.

Really good, useful point MestreLion.

Alas, an inaccurate one.

The relevant section of the SDK is CvCity::doGreatPeople(), in CvCity.cpp.

Every turn, two functions are called. CvCity::changeGreatPeopleProgress() is bumping up the GPP counter by CvCity::getGreatPeopleRate(), which is exactly what it sounds like: how many GPP per turn are we generating.

The code then loops through every UnitType, calling CvCity::changeGreatPeopleUnitProgress, and bumping up that value by CvCity::getGreatPeopleUnitRate(). The GreatPeopleUnit rate is being changed by processSpecialist and processBuilding, and in each case the input is the number of specialists/buildings being added or removed from the city.

In other words, if you run 9 scientists this turn, then you increase GreatPeopleUnitProgress( GREAT_SCIENTIST ) by 9.

That means that it doesn't matter how you distribute the specialists - one artist run for 10 turns has the same effect as 10 artists run for one turn....

Except in one bizarre case, which is potentially exploitable, although I've never managed to make it large enough to be notable. It has to do with overflow - the GP points in excess of those used to produce the great person are saved, but the memory of how those points were accumulated is lost when the GP is created.

So imagine that on turn one you run a zillion scientists. So you pop a Great Scientist, but you still have a zillion uncolored points left over. So fire all the scientists, and run an engineer for one turn. Now you've got a Great Engineer, and you still have a zillion uncolored points left over. Run another engineer for one turn. Pop pop pop.

In practice, you can't get that much overflow. But you can shave a few turns off easily enough.

Hi VoiceOfUnreason

You seem to understand the code. Please, would you be so kind as to confirm or reject my 2nd trick in
http://forums.civfanatics.com/showpost.php?p=4567722&postcount=60

Basically, I am guessing that the code changeGreatPeopleProgress() is run, then a GP is generated if the total has reached the threshold. If not, then getGreatPeopleUnitRate() is used to calculate the new probability.

My trick is useless if the code changeGreatPeopleProgress() is run, then getGreatPeopleUnitRate() is used to calculate the new probability, then the threshold is checked to generate a new GP.

Thank you very much.

Bad news, jesusin: both counters are updated before the check against the threshold.


Hey, I just found another useless optimization. GP progress is checked city by city. So it's theoretically possible to get two GP to spawn during the same turn, if the second city is earning more than 100 gpp/turn (urk, or 200 gpp/turn after you've spawned 9 people).

So given equivalent cities, you should put the GP farm in the newer one.

I don't expect to be thanked until someone actually manages it in a game though - currently scheduled for the next full moon in a week with two Mondays.

100 GPP per turn only takes 1 great wonder + 1 small wonder + 7 specialists + national epic, and modifiers of philosophy leader, national epic, pacifism. 7 specialists only requires 3 corns = size 10 city. If you have more wonders then the number of specialists can be reduced further.

Not awfully difficult, at least from the face value.

@VoiceOfUnreason : Bad news, jesusin

Well, I consider it good news indeed. The program works as it should. My trick is no good but, who cares.
Thank you very much for analyzing it for me.

@Xin Yu: Not awfully difficult

I thought so at first, too. The main difficulty for me is that my GPfarm tends to be one of my oldest cities, so it is the no-farm-city the one that has to get those 100GPP.

Alas, an inaccurate one.
(...)
That means that it doesn't matter how you distribute the specialists - one artist run for 10 turns has the same effect as 10 artists run for one turn....

Not according to the OP:



* Assuming normal game speed, no great person generated yet: You hire a priest specialist for 22 turns. Then you fire him, and hire two scientist specialists for 11 turns. Intuitively, one would assume that because you had 22*1=22 sources for a great prophet and 11*2=22 sources for a great scientist, this would give you a 50%/50% chance. But because the game averages over turns, the odds will be 22/33 = 67% for a great prophet and 11/33=33% for a great scientist instead, because you had 22 turns with only great prophet sources and 11 turns with only great scientist sources.
(Thanks to Roland Johansen for suggesting this!)


If what you are saying is correct, then pretty much everything that was said before about odds in this thread is wrong. Both theories are reasonable and have their own logic. As i cant undestand SDK code, i have no clue now. Could you please double check this with Kylearan or anyone else? Can someone (who knows SDK code) please check this (great) example of "1 artist for 10 turns VS 10 artists for turn"? Would both produce the same odds against, say, 1 eng for 10 turns?

Hi,

If what you are saying is correct, then pretty much everything that was said before about odds in this thread is wrong. Both theories are reasonable and have their own logic.
I haven't followed what has been said in this thread, but want to point out that when in doubt, trust the code readers. My original post was based on trying to reverse engineer the mechanics of how GPPs work, by using experiments and observation. This method is quite error-prone by nature. If the code readers say it's working differently, then I'd trust them more than my previous work (which was based on an older patch too, by the way).

And no, I won't take a look at the code myself. I'm way too lazy for that. :p

-Kylearan

Once a wonder becomes obsolete, it will no longer produce any GPPs.

Negative. Obsolete wonders continue to produce both culture and GPPs.

To be fair though that change was made in 1.61.

Hey, I just found another useless optimization.

T-Hawk discovered a useful exploit. During Anarchy, you don't actually need to feed your citizens - you can make everybody a specialist.

So what? Specialists don't generate any GP points during Anarchy, so its a waste of time... EXCEPT that the specialists do generate source points during Anarchy.

So if you need to dilute the effect of your Artist wonders, during anarchy take all of your citizens off of the tiles, and use them as Science specialists (or whatever sort of GP you would prefer).

Exactly the same trick works during disorder when you capture a city.

My original post was based on trying to reverse engineer the mechanics of how GPPs work, by using experiments and observation. This method is quite error-prone by nature. If the code readers say it's working differently, then I'd trust them more than my previous work (which was based on an older patch too, by the way).


The version of this article that's in the War Academy should probably be updated by somebody.

And no, I won't take a look at the code myself. I'm way too lazy for that.

Somebody else, perhaps :p

One thing that I've been wondeirng about GP is do the techs you have matter at all? For instance if you have Mathematics but few religious/art techs does this help generate Scientist/Engineers over GAs, GMs and GPs?

One thing that I've been wondeirng about GP is do the techs you have matter at all? For instance if you have Mathematics but few religious/art techs does this help generate Scientist/Engineers over GAs, GMs and GPs?

Techs have no direct effect; they aren't part of the calculations at all.

Techs have no direct effect; they aren't part of the calculations at all.

Does getting a GP by being first to a GPTech effect your GPP in anyway?
Does it make it take longer to get the next GP?

Does getting a GP by being first to a GPTech effect your GPP in anyway?
Does it make it take longer to get the next GP?

No (he said confidently, without checking the code...?)

So what? Specialists don't generate any GP points during Anarchy, so its a waste of time... EXCEPT that the specialists do generate source points during Anarchy.

So if you need to dilute the effect of your Artist wonders, during anarchy take all of your citizens off of the tiles, and use them as Science specialists (or whatever sort of GP you would prefer).

Exactly the same trick works during disorder when you capture a city.

:D That's just funny. But a good idea is a good idea.

100 GPP per turn only takes 1 great wonder + 1 small wonder + 7 specialists + national epic, and modifiers of philosophy leader, national epic, pacifism. 7 specialists only requires 3 corns = size 10 city. If you have more wonders then the number of specialists can be reduced further.

Not awfully difficult, at least from the face value.

That could even be done with just 3 floodplains, size 7.
Library, Great Library, National Epic
Caste System, Mercantilism, Pacifism.
100GPP/turn

wow great explanation. this really cleared up my understanding of generating great people.

It appears that the game mechanic has changed in BTS.

CvCity.changeGreatPeopleUnitRate is now called with passed the gp rate.


changeGreatPeopleUnitRate(eGreatPeopleUnit, GC.getBuildingInfo(eBuilding).getGreatPeopleRateCh ange() * iChange);


Which means that the probabilities of GP points are now based on points where they used to be based on sources.

In other words, where 20 turns of oracle plus 20 turns of scientists used to leave you at 50/50, now you are at 40/60 favoring the scientist.

It appears that the game mechanic has changed in BTS.

CvCity.changeGreatPeopleUnitRate is now called with passed the gp rate.


changeGreatPeopleUnitRate(eGreatPeopleUnit, GC.getBuildingInfo(eBuilding).getGreatPeopleRateCh ange() * iChange);


Which means that the probabilities of GP points are now based on points where they used to be based on sources.

In other words, where 20 turns of oracle plus 20 turns of scientists used to leave you at 50/50, now you are at 40/60 favoring the scientist.

That's a major change. I don't know if it's better now or if it was better before. It does mean that such small wonders like the Globe Theatre and the National Epic don't ruin your great person farm as badly with great artist influence as before.

That's a major change. I don't know if it's better now or if it was better before. It does mean that such small wonders like the Globe Theatre and the National Epic don't ruin your great person farm as badly with great artist influence as before.

On the other hand, it really ruins your choice if you used several engys for a few turns to speed up a building, or several merchants for a quick income.

I guess theres no "better": if you plan ahead, based on the correct formula, you can always get the results you want, one way or another.

On the other hand, it really ruins your choice if you used several engys for a few turns to speed up a building, or several merchants for a quick income.

I guess theres no "better": if you plan ahead, based on the correct formula, you can always get the results you want, one way or another.

Reading your post, I started wondering about another strange effect of the great person generation. Namely that the chance of a certain type of great person is determined by the chances of the various great persons in a turn and then averaging it over the turns instead of just averaging it over all of the various great person points that have been generated.

It was so that if you used one engineer for 19 turns and then 19 artists during one turn, then the chance of a great engineer was 95% (19 turns with 100% engineer, 1 turn with 100% artist). Will it now be 50% (19 out of 38 specialists used were engineers)?

Do you know, VoiceOfUnreason?

It was so that if you used one engineer for 19 turns and then 19 artists during one turn, then the chance of a great engineer was 95% (19 turns with 100% engineer, 1 turn with 100% artist).

From the time that I started looking at this, that wasn't so. The comments you'll find scattered about CFC indicate that many people thought that it had been this way. Maybe it was, once upon a time.

I'm very certain it hasn't been that way since I started paying attention to this code. I don't know for sure when that was, but a quick search shows that was at least a year ago.

Anyway, for the last year and change, the answer has been 50-50.

From the time that I started looking at this, that wasn't so. The comments you'll find scattered about CFC indicate that many people thought that it had been this way. Maybe it was, once upon a time.

I'm very certain it hasn't been that way since I started paying attention to this code. I don't know for sure when that was, but a quick search shows that was at least a year ago.

Anyway, for the last year and change, the answer has been 50-50.

That's indeed new for me. The War Academy article that's based on this thread and the first post in this thread still mention the old formula based on the number of turns and thus the 95-5 result. It should be updated.

Thanks for the information. :goodjob:

Once the threshold is reached and a great person is generated, the city "forgets" which types of sources there had been before and starts anew. So if you hire a scientist to produce a great scientist, and after generating that great scientist remove the scientist specialist and hire a priest instead, you will have a 100% chance of getting a great prophet as the next great person, since the city will have forgotten that there had been a great scientist source in the city during the previous cycle.

Does the excess GPP from the previous cycle have a source?

Does the excess GPP from the previous cycle have a source?

No, it doesn't.

Just looked at the code, some excerpt how buildings calculate great people rate:
The change for base is exactly the same as the great people type.

changeBaseGreatPeopleRate(GC.getBuildingInfo(eBuil ding).getGreatPeopleRateChange() * iChange);

if (GC.getBuildingInfo(eBuilding).getGreatPeopleUnitC lass() != NO_UNITCLASS)
{
eGreatPeopleUnit = ((UnitTypes)(GC.getCivilizationInfo(getCivilizatio nType()).getCivilizationUnits(GC.getBuildingInfo(e Building).getGreatPeopleUnitClass())));

if (eGreatPeopleUnit != NO_UNIT)
{
changeGreatPeopleUnitRate(eGreatPeopleUnit, GC.getBuildingInfo(eBuilding).getGreatPeopleRateCh ange() * iChange);
}
}


The selection of the born person is proporational to the rate:


int iTotalGreatPeopleUnitProgress = 0;
for (int iI = 0; iI < GC.getNumUnitInfos(); iI++)
{
iTotalGreatPeopleUnitProgress += getGreatPeopleUnitProgress((UnitTypes)iI);
}

int iGreatPeopleUnitRand = GC.getGameINLINE().getSorenRandNum(iTotalGreatPeop leUnitProgress, "Great Person");

UnitTypes eGreatPeopleUnit = NO_UNIT;
for (int iI = 0; iI < GC.getNumUnitInfos(); iI++)
{
if (iGreatPeopleUnitRand < getGreatPeopleUnitProgress((UnitTypes)iI))
{
eGreatPeopleUnit = ((UnitTypes)iI);
break;
}
else
{
iGreatPeopleUnitRand -= getGreatPeopleUnitProgress((UnitTypes)iI);
}
}



Thus, sources are not just counted by multiplied by their respective value. Hence it works like it shall be naturally expected.
-----
Note: that's the code provided w/ 3.19

So if i had a scientist spcialist and the oracle, the odds would be 67% Great scientist, 33% Great Prophet?

Hmm no, oracle is 2 GPP, spec is 3GPP, right;
so assuming they have started together: you get 2/5 odds for prophet and 3/5 for scientists.
Why would you think of 2/3 odds?!

My bad .... i thought Oracle was 1 GPP & the specialist was 2 GPP ... :blush:

Thus, sources are not just counted by multiplied by their respective value. Hence it works like it shall be naturally expected.
-----
Note: that's the code provided w/ 3.19


Right. The mechanic changed in some patch, I think the first version of BTS. Now, the birth chance is based on the total points for each type, not the number of source-turns for each type.

That's a major change. I don't know if it's better now or if it was better before. It does mean that such small wonders like the Globe Theatre and the National Epic don't ruin your great person farm as badly with great artist influence as before.
=.=

Can't anybody correct the original article? Not all people will read the whole topic to the end (if they come to the topic at all after reading the article) and right now the article is wrong and misleading.

No, the article is perfectly correct ... if you play in Vanilla or Warlords, that is. A mod putting a flag denoting that would be nice though....

All you have to do is PM Kylearan (the OP) and ask him to update it. He's still active.