Questions about how experience is gained

[MaroonMaurader]

If you're using something like a single-troll stack, stronger towers and heroes that summon might give you a noticeable gain in dragon xp if you leave them around for a while.

As far as hero experience from summons, I just finished some simple testing by loading up old saves.

I fought Samman twice; once he used demon portal to summon 11 executioners, the other time to summon 11 executioners, 13 demons, and 24 demonesses. Both fights gave 22,204 experience.
I fought K'Tahu twice (cheating in advance to bump my leadership up to 120k to speed things up and make results easier to control); once he summoned 16 tirex and 207 hayterants. The second time he summoned 17 tirex, 674 gorguls, 74 brontors, and 241 gorguanas. Both fights gave 41,401 experience.
I fought the Pendant of Hypnosis twice. Once the gremlin towers summoned no units. The second time the gremlin towers summoned 9 beholders and 19 inquisitors. Both fights gave 520 experience.
I fought the Druidic staff twice. Once no units were summoned. The second time the druids summoned 100 bears, although the friendly griffin towers still summoned nothing. Both fights gave 2,176 experience.

[loreangelicus]

This is very sad... so ancient knowledge scrolls are still the only way to hit level 60+.

[DGDobrev]

Yes. It appears that summoned units do not provide any XP at all.

[WhYdOyOuThInKtHaThApPeNeD]

Happened to be in a Chosha battle so let them summon for 101 rounds to see what the scores show. Over 200 Adult Gobots per round. Confirmed here also.

[MaroonMaurader]

Ok, here it is: the answer to all questions about how combat experience is gained. There are a few small points I had to make an educated guess about, but almost all of this is directly from the game files.

Experience gain after battles is controlled by a little function called arena.lua which is packaged into sessions.kfs. That function also handles gold earned from battles and a lot of record-keeping for end of game stats, and it might manage a few other things too (there are a few lines of code I wasn't too clear on). However, the basic formula is as follows:

experienceGained = [(total enemy leadership)*(leadership multiplier) + (boss experience)] * (1 + experience bonuses) * (enemy hero multiplier) * ("fake win" multiplier)

Total enemy leadership is the total pre-battle leadership of the enemy stack. It doesn't count summoned units, nor does it count the increase in leadership ghosts get from attacking, nor does it count anything else that might come up during the battle.

Boss experience is exactly what it looks like. Bosses are worth experience. You can read exactly how much if you want to check their .atom files in \data\data.kfs: 8000 for toad, 10000 for driller, 16000 for gremlion, 20000 for k'tahu, and 26000 for Baal.

The leadership multiplier is 0.017; you can find it in logic.txt in session.kfs. There's a little comment indicating that they might have thought it was actually 0.16, but I'm pretty sure that's not true - ivra's numbers don't add up if you use a 0.016 multiplier.

The experience bonuses are additive, not multiplicative. So a 20% leadership boost, plus a 5% boost from the medal, gives you (1 + .2 + .05) = 1.25 as a multiplier, not (1.2*1.05)=1.26.

The enemy hero multiplier is 1 if there is no enemy hero or if there is an enemy hero of level 0 (I'm not sure if this ever exists). Otherwise, it's 1.5 + 0.03*(enemy hero level); to give an example, a level-10 enemy hero boosts experience by a factor of (1.5 + 0.03*10) = 1.8.

I'm not totally sure what the "fake win" multiplier applies to, but I think it's for keeper battles (and maybe a few other weird battles?). It's 0.7 if your victory was a "fake win," and 1 if it was a normal win. You can check that too in logic.txt. Also, I'm pretty sure that gremlin towers in keeper battles don't give experience (their .atom files have no leadership entry and no experience entry, so I'm not sure where the game could get an experience value for them from).

Anyhow. I'm not sure how useful any of this information is, but I've been curious for a while about it so I went and looked into it, and now I figured I'd post it in case anyone else was curious.