A Quick Introduction
Hello Everyone! Since this is my first post on the 0AD forums, i would like to start with a quick introduction. I've come to know about 0AD quite recently and been playing it since May 2021 (single-player). I have played quite a few RTSs already (namely Age of Empires II, Age of Mythology, Warcraft 3 and StarCraft), but this was the first game that i ever saw a Batch Training mechanic and i love it!
Fun aside though, i also started doing some tests to try and use this mechanic to it's fullest potential. In this regard, 0AD sets itself apart from those other games i mentioned because it is an Open Source Project so I could go through the code more easily to unearth the formulas, modifiers, etc in order to make my analyses. So without further ado, let's do some math!
The Mechanic Unveiled
First things first: How is Batch Training implemented?
As far as resource costs and population growth is concerned, there are no changes, but training time (for each individual unit) is greatly reduced using the following formula:
BatchTime = BaseTime * (#Units ^ Mod)
Where:
BaseTime = The time it takes to train a single unit
#Units = The size of the group
Mod = Modifier, a value that is intrinsic to the Building Type and determines the reduction in Training Time.
List of Modifiers:
Houses: 1.0 (meaning, Batch training in houses does not reduce training times)
Corral, Market, Siege Workshop, Elephant Stable, Special Buildings: 0.7
Barrack, Stable, Fortress, Civic Centre, Carthage Embassies: 0.8
Let's illustrate this with an example:
Unit:
Spartan Hoplite – From Civic Center (Mod: 0.8)
BaseTime = 10 secs
#Units
1 by 1 - Time (s)
Batched Time (s)
2
20
17.41
3
30
24.08
4
40
30.31
5
50
36.24
So, as seen in the exemple above, Batch Training reduces the training time of units considerably and, on the surface, it appears to be always better to Batch train instead of training 1by1.
However there is a tradeoff. You'll only have said units at the end of the entire Training period (which is longer than the time to train a single unit). What this means is that 1by1 will give you readily available units sooner, but in smaller quantities, while Batching will give you readily available units later, but in larger quantities.
This is a point to consider, specially in the early game, where we want to gather resources as fast as possible to build up our economy and our army. If we call the amount of time a unit is out on the map ActiveTime (as in it can perform actions such as move, gather, fight, etc), we can say that the method that gives us more ActiveTime overall will be better.
Analysis
Let's use our Spartan Hoplite to understand this problem.
Spartan Hoplite – From Civic Center (Mod: 0.8)
BaseTime = 10 secs
Let's say we train 2 units using both methods:
From our table we gather that 1by1 will produce a unit after 10 secs and another after 10 more seconds, while batching will produce 2 units after 17.41 secs. This means that both methods don't generate any ActiveTime in the first 10 seconds (since no units are out yet) and will start generating the same amount after 20 secs (when the second unit of 1by1 gets done). So what we can compare is the amount of ActiveTime generated after 10 secs but before 20, for both methods. Do note that each unit out on the map generates 1 sec of ActiveTime for each in-game second. This means that 2 units will generate 2 secs for each in-game second and so on. With that in mind we can do the calculations and reach the following table:
#Units = 2
Time Elapsed (s)
1 by 1
Batching
#Units Produced
ActiveTime(s)
#Units Produced
ActiveTime(s)
0
0
0
0
0
10
1
0
0
0
17.41
1
7.41
2
0
20
2
10
2
5.18
#Units = 3
Time Elapsed (s)
1 by 1
Batching
#Units Produced
ActiveTime(s)
#Units Produced
ActiveTime(s)
0
0
0
0
0
10
1
0
0
0
20
2
10
0
0
24.08
2
18.16
3
0
30
3
30
3
17.76
#Units = 4
Time Elapsed (s)
1 by 1
Batching
#Units Produced
Total ActiveTime (s)
#Units Produced
Total ActiveTime(s)
0
0
0
0
0
10
1
0
0
0
20
2
10
0
0
30
3
30
0
0
30.31
3
30.93
4
0
40
4
60
4
38.76
As we can see, although batching reached the total amount of units faster than 1by1, that amount of Active time generated in the same period heavily favors 1by1. Now let's see if this trend continues and calculate the percentages to see by how much 1 by 1 is beating Batching.
# Units
1 by 1
Batching
Percentage (%)
Total ActiveTime (s)
Total ActiveTime(s)
2
10
5.18
51.8
3
30
17.75
59.17
4
60
38.74
64.57
5
100
68.81
68.81
6
150
108.42
72.28
7
210
157.97
75.22
8
280
217.76
77.77
9
360
288.04
80.01
10
450
369.04
82.01
27
3510
3519.02
100.26
Interesting! As we increase the amount of units trained, Batching slowly catches up to 1 by1 and by the time we reach 27 units, Batching will match 1by1 in Total ActiveTime generated. We can also see that any number of units above 27, Batching will start becoming more and more efficient.
Naturally, 27 units costs an unfeasible amount of resources and time (specially in the early game) so we can conclude that by our metric of ActiveTime 1by1 is by far more productive than any amount of batching we can get in the early game.
Conscription
In the City Phase (last phase) we get access to the Conscription technology (in the barracks and the Stable). This technology lowers the Batch Training modifiers by 10% (Mod = 0.8 to Mod: 0.7) and that is a huge change. Lets do the same calculation, but now with Mod = 0.7.
# Units
1 by 1
Batching
Percentage (%)
Total ActiveTime (s)
Total ActiveTime(s)
2
10
7.51
75.10
3
30
25.27
84.23
4
60
54.44
90.73
5
100
95.74
95.74
6
150
149.69
99.79
7
210
216.68
103.18
This means that in the late game (after researching Conscription), given enough resources, any Batch amount > 6 will be more efficient than training 1by1. That is also valid for all the buildings that naturally have Mod = 0.7.
Discussion
So, the main question that arises from this analysis is: Is the Batch mechanic useless in the early game? My answer is NO and here is my reasoning.
THE GOOD:
- Batching is great for early game rushes and timing attacks: since we'll be able to pump units much faster that by building 1by1 and we can't afford to build multiple barracks or stables in the early game.
- Batching is great for dumping excess resources: Stockpiling resources isn't advisable, since resources don't produce anything while sitting in the bank. Unfortunately it happens sometimes, so if we find yourselves with excess Food, we can just build a Stable and Batch train some horses to explore the map and harass our opponent.
- Batching gives options instead on limiting them: If Batching was universally better than 1by1 then there would be no point in having having a choice. By having it's drawbacks, Batching gives more variety to the game by enabling certain strategies.
THE BAD:
- Batching is less flexible than 1by1: By Batching, we sink a lot of resources and have to wait a considerable amount of time for them to bear fruits. This means that if we need to cancel some of our productions in other to gather resources to build an upgrade or advance phases, the amount of time lost training that group can be great.
- Batching eats a lot of population: Population is also a resource. So if we want to Batch train a large group we need to have space available. Also, we'll need to quickly build houses to open more space to not get capped and keep producing out of our other buildings.
THE UGLY:
- Batching is eclipsed by 1by1 for economy: Since much of our goals in the early game is to boost our economy as fast as possible (and we do that by maximizing ActiveTime), batching does the exact opposite of what it's expected of it. And now in A25, the introduction of the Autoqueue mechanic basically kills batching even more for early game economy.
Closing Remarks
Well, that's basically all i had to say about the subject. I hope this post wasn't too boring and you were able to enjoy it. I would also like to read your opinions and comments on the matter. If you agreed or disagree with this analysis and why? Any concerns or constructive criticisms are always welcome. See you on the forums and have fun!
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TL;DR (just in case)
Which is more efficient in the early game: training in batches or training units 1by1?
Well, 1by1 will give you readily available units sooner, but in smaller quantities, while Batching will give you readily available units later, but in larger quantities.
By comparing the Total ActiveTime (the amount of time a unit is on the map, ready to move, gather, fight, etc) in both approaches, we get:
- From the Barracks, Stable or Civic Center: 1by1 is more efficient if the batch size is smaller than 27. Since batches of 27 are basically impossible in the early game, for economy purposes, 1by1 if far better than any amount of batching.
-Batching is better than 1by1 in strategies involving rushes or timing attacks.
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EDIT 1:
So, considering what @Jofursloft and @Freagarach have said in the their posts, i redid the calculations for batching and 1by1 considering more productions cycles and the ProgressTimeout delay that autoqueue gives. To avoid making this post bigger than it already is, i placed the the calculations and the result tables in the attached pdf.
In general, smaller batches (2 to 3 units) break even with 1by1 by the 3rd production cycle, while bigger batches (5 and upwards) break even by the second production cycle. Things are a bit less efficient if you use autoqueue, but not by much.
So, as long as you can batch units constantly, batching will always be better than 1by1. Also, the bigger the batch size, the better.
Batching Revisited.pdf