MP Calculation Change/Decapping

[bcadren]

Amnesiac brought up in the IRCchannel that DE's capping at 50 MP and humans at 49 was so negligible a difference to make choosing a race with low HP/high MP apts a bit unbalanced compared to the opposite (other apts notwithstanding). This lead to me playing around with the MP formula a lot and trying to come up with something that both gave a bigger difference in what apts did and didn't slow down gaining MP so much past lair. (I noticed in wizard mode that regardless of race between 12-15 XL and SplCast the player hits 40 MP and only gains one every 3-4 levels of both past that.) I know it's worth discussing both of these points:

• The MP apt. needs to have a larger effect than it currently does on par with the HP apt.
• MP gain step down shouldn't slow SO much past lair.

I played around with different formulas for a bit to try to come up with something that approached this, while remaining attached to the current one. I'm not sure if I'm happy with what I came up with, because as well as making the MP apt. matter more and boosting MP amounts in late game; it nerfs MP amounts before Level 10/SplCast 10 a bit, which I didn't strictly think was necessary. Nonetheless, I think it's worth playtesting and I made a chart of a human (using only level and splcasting) to show how this might play out theoretically.

MP = (1 + Aptitude/10)*(XL + (XL + 1)/3 + max(Spellcasting*XL + Spellcasting, (Invocations*XL + Invocations)/3, Evocations*XL/6))^0.65
Chart

Again: I'm not sticking by that formula; it's just a concept. The two precips that MP apts. should have a larger effect and MP should continue to gain at a noticeable rate past level 12-15 I do stand-by though.

[Amnesiac]

Yes, the idea is that DE get -20% hp and no particular advantage from +30% mp later in the game when they hit the cap. I'm not sure that that formula works, but I think DE should cap at 64 mp or something(or not cap at all, because I don't see much point in stepping down those 9mp from rings), for +30% mp to actually be a thing until the end of the game.

[and into]

Current proposal is a strict nerf for lots of characters during the time when MP costs matter the most. The difference between 9 (proposed) and 12 (current) MP for a level 8 character with 2 spell casting is considerable, for instance. On the other end of the spectrum, allowing 70+ MP for high level seems bad.

Having more MP for early and mid game is strong; something not being particularly advantageous when you have already gotten to mid-twenties level with high spell casting does not mean it is weak.

However, if MP aptitude were to be made more meaningful and get a buff, I think the best approach would be a straight buff rather than fudging with MP growth for everyone (which would introduce issues with rebalancing).

So how about this:

Keep growth as is currently, make 49 the usual cap for all species though. In addition to faster growth throughout the game (as currently), having a good MP aptitude also gives following bonus:

Tier One: +1 MP at start and additional +1 MP every 4th level. These additional MPs ignore cap of 49. (Max mp 55) [Tengu, Demigod, High Elf, Felid]
Tier Two: +2 MP at start and additional +1 MP every 3rd level. These additional MPs ignore cap of 49. (Max mp 60) [Deep Elf, Spriggan]

Numbers can be tweaked obviously but I think a simpler solution along these lines might be better than rejiggering the whole MP growth formula.

[Amnesiac]

Yeah, we are not fixed on that formula, like bcadren said. The point is to make mp apt relevant at higher levels. As I'm seing mp aptitude, as it most of the time counterbalanced by hp aptitude, species with a higher mp aptitude are made this way to rely more on mp to make up for a lower hp apt, so I should probably stay this way after hitting the current cap. Why does this cap exist anyway? So what if someone decides to wear rings of magic power(or what was it called) instead of semething else is that so OP'ed so it sould be nerfed by a cap? IMO a lot of other rings are usually more useful either way.

[some12fat2move]

We could simply have the cap be modified directly by MP aptitude. So say the cap is 40: with a +10% mp aptitude, the cap becomes 44; with a +20% mp aptitude, the cap becomes 48; etc. But of course, removing the cap would be even simpler, imo there's no reason for it.

[bcadren]

One of the problems with a 'just change the cap' mentality is that as far as I understand it the MP goes through two calculations.

The first one uses Level, Spellcasting, Evo and Invo to get your 'raw' MP. The second steps down the raw MP to a more reasonable number.



I don't know what it is exactly, but it's essentially a logarithmic curve such that 0 = 0; 200 = 49 and lim x->∞ = 50.
[I'm going by the wiki here so someone with source access feel free to correct if it isn't true; but this particular wiki page even listed how things were changing for 0.14 so I feel inclined to believe it is accurate and up-to-date.]

So when we say 'remove the cap' what we really mean is change the stepdown function; because WITHOUT IT, a human would have 197 MP.
Changing the stepdown and making apts matter more is what I tried to do, but instead of a logarithmic stepdown I used a cube root one and changed the base formula a bit (made the skill matter a little more [roughly equal to level instead of much less] and apts matter A LOT more)

I can play with formulas more, but really we are talking about finding the right amount for various things to matter (0.14 is making evo and invo only result for less mp than Spellcasting)...then scaling/stepping it down in a way that it makes an appropriate level curve (being perfectly linear would be horrible).

[damiac]

You could overlap the old and new curves, and use the value of whichever gives the highest number. Therefore the level 8 character can keep his 12 mp, instead of going down to 8, but the level 27 character can have 70 mp instead of 50.

The only really big balance issue with this is from anything that fills your MP to max, otherwise it's only beneficial at the beginning of a fight anyway. (meaning, if you had 50 mp, and used it all up, then channel mp back to 10, and cast more, etc, that extra 20 mp is only useful before you use it up, the channeling isn't affected anyway)

[Viashino_wizard]

You could overlap the old and new curves, and use the value of whichever gives the highest number. Therefore the level 8 character can keep his 12 mp, instead of going down to 8, but the level 27 character can have 70 mp instead of 50.

The only really big balance issue with this is from anything that fills your MP to max, otherwise it's only beneficial at the beginning of a fight anyway. (meaning, if you had 50 mp, and used it all up, then channel mp back to 10, and cast more, etc, that extra 20 mp is only useful before you use it up, the channeling isn't affected anyway)

Max MP affects your MP regen, so it still has an effect once you're down to channeling (albeit a small one).

[duvessa]

On the other end of the spectrum, allowing 70+ MP for high level seems bad.

allowing 70+ MP would be harmless and is the correct way to fix this. it's not like ring of vitality is overpowered for ogres
a ring of magical power is already worse the more MP you already have (the difference between 5 and 14 mp is a lot more noticeable than that between 40 and 49 mp) and there is no reason to make it even more useless once you reach 50, and honestly i'd consider going from 5 to 10 mp much more important than going from 50 to 100 mp. if i have to cast iron shot 8 times in a row then i have much bigger problems than using my 50 mp; having more isn't really that much of an advantage, especially since crystal balls etc. exist anyway. the mp cap is just one of those things in crawl that's been around forever and has no reason to stay around, and i say get rid of it so that people like bcadren and you stop being fooled into thinking it's important, because it isn't

[dpeg]

Species petering out at the same amount is not the end of the story, as andinto has explained: having more MP during the early and mid game is a crucial bonus, and I wouldn't want to spoil that visible effect for some late game change.

[pubby]

Speaking of MP capping, is there really a need for extra MP (from ring of magical power) to be halved when you have more than 50 MP?

[bcadren]

Species petering out at the same amount is not the end of the story, as andinto has explained: having more MP during the early and mid game is a crucial bonus, and I wouldn't want to spoil that visible effect for some late game change.

It's never as substantial a difference as HP, which is part of the point. At it's widest point; the difference is 4MP at 12-12 (28-32) [I didn't try every combo, because that would take forever in wizard mode]. In short, at the beginning of the game it's a difference of only 1-2 (depending on your starting Spellcasting), it widens to 4-5 by Mid Lair, at goes back to one by the end 1 at max stats. Very little effort to gain MP early; by lair and early mid-game it plateaus into slow growth and by the end additional levels or Spellcasting do nothing. Some of the other magic Apts. make Magic affine characters worth it, but the HP/MP apt. trade off isn't what you'd think.

Addendum:
HP Apt. and Robust/Frail are similar bonuses/maluses. Really for HP Apt/MP Apt trade off to be fair at very least the same should be true of the MP Apts relationship to its mutations.

[FalconNL]

Just adding my support behind increasing the max MP, particularly for characters like Deep Elves who put so much effort in specializing in magic. With the current 50 MP, casters just feel far less powerful than melee characters, at least when limiting the scope to a basic 3-rune game. I can't speak for extended, since I've only bothered doing a 15-rune game with a caster.

Let's take my most recently won game as an example: MiDK of Yred, Maxwell's patent armor, +14ish Wyrmbane, a decent-sized undead army at my beck and call, doing one of the big vaults in the Depths (nooodl_heptagram). I see a group of 10+ enemies. Charge! A few dozen turns of pressing tab later, the enemies lie splattered all over the dungeon floor and I've lost maybe 25% of my health. Oh look, another group of enemies has come looking what all the racket was about. Follow me, minions! To glory!

Compare that to my current game, where I'm also in Depths, this time playing a DECj of Sif. I carefully approach the entrance to one of the big vaults (minmay_spriggan_fort, I believe). An enemy appears. Cast IMB. My battlesphere times out, as usual. Re-summon IBS, cast two more IMBs, monster dies. With about a third of my MP gone, it's about time to retreat and start resting before another monster wanders up... yeah, just like that one, in fact. Another few IMBs and it goes down as well. Ok, now I really need to go. Three more monsters come looking. I start walking backwards, only to find another monster has come up behind me. Granted, actually getting away is never too difficult thanks to some combination of swiftness, haste and cBlink, but the simple fact is that I need to start thinking about running whenever I encounter any group in excess of three or so, whereas with a decent melee build I can easily handle a dozen.

Of course I realize there's a balance here, since if things ever got really dicey for my MiDK he would be screwed (no spells, no blinking or teleporting), but shouldn't someone who has taken the time to learn how to manipulate the very fabric of reality at least be able to somewhat match the killing power of a glorified cow with a pointy stick? Increasing the maximum MP to something like 80 should go a long way towards achieving this.

[crate]

At it's widest point; the difference is 4MP at 12-12 (28-32)

these numbers the way you are presenting them are meaningless

A difference of 1 mp on turn 0 is absolutely enormous for many characters, whereas a different of 1 mp at xl27 is not even noticeable. Deep elf MP is absolutely noticeable for the parts of the game where it matters the most.

If you want MP apt to be more important later in the game, my suggestion is to just simply remove the 50 MP cap entirely with nothing done in exchange, like minmay already suggested (except fixing the bug I reported some time ago leading to negative MP if you save with 128+ current MP, since this would be a thing that might actually happen to players instead of a thing I only found while experimenting).

[and into]

On the other end of the spectrum, allowing 70+ MP for high level seems bad.

allowing 70+ MP would be harmless and is the correct way to fix this. it's not like ring of vitality is overpowered for ogres
a ring of magical power is already worse the more MP you already have (the difference between 5 and 14 mp is a lot more noticeable than that between 40 and 49 mp) and there is no reason to make it even more useless once you reach 50, and honestly i'd consider going from 5 to 10 mp much more important than going from 50 to 100 mp. if i have to cast iron shot 8 times in a row then i have much bigger problems than using my 50 mp; having more isn't really that much of an advantage, especially since crystal balls etc. exist anyway. the mp cap is just one of those things in crawl that's been around forever and has no reason to stay around, and i say get rid of it so that people like bcadren and you stop being fooled into thinking it's important, because it isn't

Well I actually think ring of magical power (or staff of power) shouldn't be subject to a weird step down, either. My main objection as I made clear is that altering how MP growth occurs for all characters seems like a needlessly intrusive and weird way to add value to having good MP aptitudes.

[Amnesiac]

Actually, my initial idea was just that the cap should be proportiopnal to the MP apt, at least. But it's easy to realise that there is no actual need for a cap. Still, if making a natually gradual growth of MP go to reasonable amounts is more complicated than I think, the cap can stay and just be proportional to the MP apt, but the stepdown for after cap MP should really be removed, we don't need to make mp rings more useless than they are before the cap.