Surrounding the enemy gives Negative Bonus?

[Lyrrix]

So... I've just surrounded my enemy's city as much as I possibly can before I get to Mountaineering, but for some odd reason, it's giving my unit a -51% "bonus" for surrounding my enemy... isn't that exactly the opposite of what it's supposed to do?


Image:

Spoiler :

(Currently playing version 34)

Edit: Nevermind... the negative seems to merely be a graphical error... it's actually working the other way around. Still... a bit annoying, no?

 

[Thunderbrd]

Green means its working FOR the attacker. The - is under the modifiers being applied to the longbowmen so actually, that could be perceived as correct. But some of the thinking on those modifiers aren't keeping aligned... the +33% vs archers makes sense but should perhaps be a modifier to go under the attacker's list instead of the defender's. It's kinda a mess and has been for a while and at some point I'll go in and make sure that they all display with one line of thinking.

Sorry it's a bit confusing.

 

[God-Emperor]

Edit: Nevermind... the negative seems to merely be a graphical error... it's actually working the other way around. Still... a bit annoying, no?

Well, no.

Everything listed under the enemy unit is a modifier applied to the enemy unit. All the modifiers for you unit are shown under the X vs. Y strength line, above the enemy unit type line (there might be a BUG option to turn on a line that gives the type of unit yours is below that "vs" line and above the modifiers for you unit).

The color shows the source of the modifier, not which units it applies to (red for things from them, green for things from you).

You (since it is in green) are giving them a -51% modifier which is obviously not good for them. It is hard to tell from the small text but it looks like your attacker has a -33% vs archery units which shows as +33% (I think) for the enemy longbowman.

It is a peculiarity of the Civ4 combat system that all modifiers except plain +X% combat modifiers from promotions are actually applied to the defender. The +50% vs. melee that an axeman gets is applied as a -50% modifier to the defender if it is a melee unit, for example.

 

[BlueGenie]

Does that mean that a +50% vs a type is actually +100% then?

Cheers

 

[God-Emperor]

No.

If the sum of the modifiers is positive they are applied directly to the defender's strength, so +50% is done by multiplying by 1 + (sum of modifiers) = 1 + 0.5 = 1.5. Like 6 * 1.5 = 9.

If the sum of the modifiers is negative they are applied by dividing the defenders strength by a value which is 1 - (total modifier), so -50% is done by dividing by 1 - (-0.5) = 1.5. Like 6 / 1.5 = 4.

In cases where the defender has no bonuses this is mathematically identical to applying the bonus to the attacker. X vs Y/1.5 (like 6 vs 4 when X and Y are both 6) is the same odds as X*1.5 vs Y (like 9 vs 6 when X and Y are both 6) since in both cases the attacker ends up 50% stronger than the defender.
With modifiers from both attacker and defender it often works out differently since X * 1.5 vs Y * 1.25 is not the same as X vs Y / 1.25.
Example: 5 * 1.5 vs 6 * 1.25 is 7.5 vs 7.5 which is even and therefore a 50% chance of the attacker winning,
but 5 vs 6 / 1.25 works out to be 5 vs 4.8 which is not even and gives the attacker more than a 50% chance to win.

Various analyses of this have been done in the forums, explaining what it all means for cases when the attacker gets more bonuses or the defender does and how the combat bonuses which are applied to the attacker affect the situation, and what effect first strikes add to the various situations. The combat in civ 4 is not exactly intuitive and this "almost all bonuses are applied to the defender" thing is one of the major reasons, which is why all the threads talking about this exist.