13-02-2001 23:41									#1
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Commerce is another one of those mysterious quantities that appear in the game. It especially seems to confuse things in multiplayer. Some people are reluctant to make treaties or pacts with Morgan players, thinking they are being "ripped off" somehow. Actually, commerce creates a global economy where all players benefit. The more energy any one faction makes, the more everyone makes. Intelligent human players can optimize their commerce with pactmates in ways that AI factions never do. For example, concentrating energy production in a few key high-energy bases benefits commerce.

Below is an actual example of commerce in a 7-player game. At the beginning, all 7 factions had pacts with each other.

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	13-02-2001 23:42									#2
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lobal Commerce: Effects of repealing Global Trade Pact and Global Hostilities

In Islanders2 on ACOL, the Global Trade Pact was broken effective in 2163, and in 2166 fighting broke out between a Hive-University-Peacekeeper alliance and a Gaian-Spartan alliance with Believers and Morganites neutral. (see this link: http://www.an.i-dentity.com/ubb/For...ML/000331.html)

I thought it might be interesting to track changes in global commerce during these times. I calculated the commerce generated at each faction's top 3 bases, as determined by the Energy Reserves ranking (which does not agree perfectly with commerce ranking). So total commerce is like to be higher by at least a factor of 4 or so.

Faction 2161 2163 2164 2165 2166
G 265 133 94 137 82
H 194 96 94 97 ?
U 159 75 78 79 ?
M 194 95 89 95 128
S 149 74 76 78 65
B 132 64 66 68 63
P 307 147 131 131 ?
Sum 1400 684 628 685 ?

COMMENTS: Commerce normally rises steadily with each poassing year, as populations rise, additional terraforming is completed, and commerce-related techs are discovered (also, more bases are built, but that is not reflected in these 3-base totals). Commerce is affected by the energy production of your pact or treaty-mates bases, which includes commerce. Therefore, when commerce rates are cut the effects can be large.

In 2161, three factions had +2 economy. G were in Wealth + Golden Age, M were in Wealth, and P were in Free Market. P and G had the largest bases and had the highest commerce despite M's intrinsic bonus.

In 2163, repeal of the Gloabl Trade Pact cut commerce in slightly less than half (1400 to 684 total commerce in the top three bases of all factions). This should be compared to where commerce would have been in 2163 if it had been allowed to grow, which based on previous trends would have been about 1480. Losses were very even between factions.

In 2164, commerce continued to fall as reduced commerce income lowered the basis for commerce in the following year. Commerce resumed its normal growth in 2165.

The onset of multiple vendettas in 2166 cut commerce somewhat, but the drop would have been far greater if the Morganites had not switched to free market. The increased commerce benefited not only the Morganites themselves but also their pactmates (G, S, B). This shows that a faction's social engineering choices can outweigh a crash of the global economy and how one faction's social engineering choices can affect other factions in a trade group. (So when the AI Morgan accuses you of messing up the global economy, there is actually some kernal of truth there!)

(Information not available from hostile factions in 2166 owing to a lack of probe infiltration.)

	15-02-2001 16:06									#3
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Very interesting, thanks DDad.

	16-02-2001 03:01									#4
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There is a section about it in datalinks under commerce.

It is a matter of energy production and diplomatic relation (pact gives double of treaty) and how many "economic techs" you have discovered.

I can swear I have also seen a screen from time to time telling me my commerce rating is 5 or 8 or whatever, but looking just now I could not find it.

From my own observation it seems to go on a city to city basis. Meaning if one of your cities have a listing of commerce with Sparta - one Spartan city will have a listing of commerce to you.

Another observation is that commerce income depends on energy production of your and their city. You will not have a trade income of 20 even if you have a huge city if your trading partner have two size two cities.

Another factor seems to be distance. In some games where I was I way bigger than partners and had several trade partners it seems that cities near a faction would tend to trade ythat faction and cities near another would tend to trade that one.

So here is my guess - it seems to be calculated per city basis.

There seems to be some minimum for you before trade sets in at all (probably first economic tech)and minimum energy production of 4-5 in the city or so possibly more if treaty less if pact.

If you have both you now have a city qualifying for trade. Trading partner will be most energy producing city of trading partner(s). Amount of trade depends on energy production (and possibly size) of you and their city and your commerce rate as influenced by SE, faction, economic techs, pact or treaty and global trade pact if in place.

If you only have one trading partner and he only has three cities only three of your cities can trade. If there is more or multiple partners it will distribute according to some factors including (I think) energy production, size and distance (closer is better).

Not terribly exact but gives some idea.

	16-02-2001 05:38									#6
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While distance may not be a factor in the resulting amount of trade, I am rather certain it is a factor concerning the program deciding what partner-city to choose.

Otherwise I have encountered a series of very unlikely coincidences.

	16-02-2001 05:54									#8
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ok found it - here it is - guess youre right no mention of distance ): :

Commerce is computed base by base between factions with Treaties and Pacts, as follows:

(1) First, all bases for each faction are ranked from top to bottom by Energy output.
(2) Bases are paired off from top to bottom. If one faction has extra bases, these are ignored.
(3) For each pair of bases, sum the combined economic output and divide by 8, rounding up.
(4) Double this value if a Global Trade Pact is in effect.
(5) Now, for each individual base, the commerce formula is as follows:
(ValueFromStep4) * (CommerceTech+1) / (TotalCommerceTech+1)
(6) CommerceTech is the total # of economic technologies discovered, plus
faction & social bonuses.
(7) TotalCommerceTech is the total # of economic technologies in the game.
(8) Now, using the value from step 5, divide by 2 if no Pact (e.g. only a Treaty)
(9) Add +1 if you are Planetary Governor.
(10) Reduce to zero if sanctions are in effect against either faction.

[This message has been edited by buster (edited February 15, 2001).]

	16-02-2001 07:57									#9
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Step 3 is where the SE settings of your partner come in. The "combined economic output" is divided by eight.

Note that economic output includes energy from your workers AND energy from commerce. Note that energy from commerce is treated just like energy from your production squares in terms of applying bonuses, producing a ranking of bases when you sort them on the F4 screen and so forth. There is no difference between getting 6 energy from a borehole and getting 6 energy from your pact with Morgan. If Morgan breaks the pact, then that base loses 6 commerce energy and more than likely you will lose one point of commerce from your pact with Brother Lal, because it's based on energy production divided by eight.

Note that Morgan going from Green/Wealth to Free Market/Wealth (as the Morgan player did in the example) does not increase energy production much (+1 per square and +2 per base to start, rising to +1/square and +4 per base). BUT the commerce rating rises considerably.

Note also that commerce is calculated before efficiency. This means you can have a base that is losing 100% of its energy production to inefficiency, but it will still bring in lots of commerce. All the commerce energy will evaporate into inefficiency, but yoru pactmate still benefits to the full extent. So only the economy SE setting has any effect, not efficiency or anything else.

	21-02-2001 06:46									#11
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Well, it may not make any sense to you Fitz, but it's the case. A base's commerce is calculated before its inefficiency is calculated. A base can generate absolutely splendid amounts of commerce, and lose it all to inefficiency, I have seen this for myself. And thus, DiDad's post is absolutely correct in this respect. Whether you can make sense of it, or not

	21-02-2001 06:53									#12
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I got confused by his ordering. So what he (and you) are saying is this:

1. Commerce calculated based on energy income (before inefficiency loss).

2. Commerce income added to energy income (on yellow bar).

3. Inefficiency determined, and subtracted from total of energy income and commerce income.

ie, you see huge commerce, then lose it all.

Now I have *pats self on back*

	21-02-2001 21:14									#13
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Fitz --the ordering is correct. Commerce giveth, then inefficiency taketh away! Your outpost bases may not be be benefitting your own research or economy, but at least they are helping your pactmates!

A retraction is in order. I tested my assumptions using the scenario editor, and you all are right. You get no commerce income on commerce income. I tested this by setting up a scenario on the Islanders map with 7 factions are all in pacts. (Which is also what developed in multiplayer!) I have some interesting findings, which I will post in a new thread, such as the fact that your pactmates SE setting CAN affect your commerce income. But the critical test was when I set Morgan and Lal into vendetta with each other. They were the commerce leaders (Lal was governor, natch), and these two factions lost commerce income big time. But the other 5 factions were not affected one whit by the Morganite-PK "war". This means that there is not really a "global economy" in SMAC, it just appears that way for various reasons. The real-game examples are misleading, I fear, because of pop growth and terraforming improvements that boost energy higher with each passing year. So I was wrong.

	21-02-2001 23:55									#14
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That's what happens when you only use example and no logic. Of course, using only logic produces the same problem. You have to apply both, and then test the theory.

You still raised a very important point in this thread. SE choice affect your pact/treaty partners income, because of combined income.