Power-based pricing available (r1284)

[Polyonymous]

There are two benefits to speed. The first is improved damage. If you can reliably do 100% (or 50% hasted) additional damage per turn, you can handle tougher monsters. But the second is reduced chance of bad touble turn against you. And double moves are the kind of thing that kill you (800+ damage). Base speed 10 is an absolute must for thriving deeper than 3000'. (You can survive with less speed, but it requires stealth and extreme evasion.) Base speed 20 is a must if you want to be able to handle the nastiest monsters with reasonable safety.

If you've got a different system of modelling the power of each bump in speed, I'm interested, but I can't figure out a good way to incorporate the removal of double moves into the model other than averaging across a range of speeds which quickly gets back each speed being a linear improvement.

ie

Which +speed puts you at their speed? It's dependant on what your other items are. The tick of speed that gives the big power boost due to the change from potential double to never double isn't clear cut. If you analyze it on a continuous scale, the effects are as I described. Even though it's not continuous, the continuous case provides a good model for assessing the impact of discrete steps.

Show me a way to price items that makes things more expensive when they "put a character's total speed at +10 or more", "put a character's total speed at +20 or more", and "put a character's total speed at +30 or more". It's just not possible to price singular items as such (unless the rule of "item that gives the most speed is the only one that applies and different items don't add" is used). You're left with approximating power with the continuous case as you can't tell for certain where the discontinuities occur.

A +9 ring has a 90% chance of crossing the threshold (only if the prior speed ended in a 0 does it not occur, yes you could analyze how often speed ends in each digit, a +1 ring a 10% chance, etc, looks like the value of the threshold is spread evenly over each plus.

PS It's probably safe to assume that the most common ending digit is 0 since speed starts at +0. After that I don't know, but that would optimal give prices per +n speed of n * k1 + (if n > 10 then k2 else 0) + (if n > 20 then k3 else 0) + if n > 30 then k4 else 0). It just depends how much of the +10/+20/+30 speed advantage you want to spread over digits ending in 1 to 9 and how much to lump in on digits ending in 0. It all depends on the assumption of how common various speed modifiers on all other items are, I'd simplify and assume equally likely. I'd also probably incorporate the randomization of monster statistics that affect hp to include armor/hitroll/speed/etc, moving quickly might mean +8 to +12 or some other range around 10 which would make the bump in power spread out over a range of speed.

[Polyonymous]

I am currently coding this into FAangband for the next version.

How far are you going? Just tossing out ideas

RES_COLD=10 | ... # assuming 10 = 10%

Do multiple resist sources add? multiply? (two ten percent resists are the same as one 19% resist, as 90% * 90% = 81%) maximum counts? Can it be negative? If negative, the multiply case might confuse users is special as -10% and +10% don't add to 0% (it's 90% damage * 110% damage which is 99% damage)

The multiply with negative effects case was so special that World of Warcraft changed the in game descriptions of effects so that players could add things up rather than multiply. If I recall correctly, a tooltip that says decreases by 25% actually means the effect occurs at 80% efficacy, which is the amount that would balance out another increase by 25%. (80% * 125% = 100%)

[Nick]

How far are you going?

All pval quantities (stats and stealth etc), brands and slays. Resistances have been percentage based for some time.

Do multiple resist sources add? multiply? (two ten percent resists are the same as one 19% resist, as 90% * 90% = 81%) maximum counts? Can it be negative? If negative, the multiply case might confuse users is special as -10% and +10% don't add to 0% (it's 90% damage * 110% damage which is 99% damage)

They multiply, and negative ones do happen. As far as representing goes, I give the actual percentages in the object description, and show the overall percentage on the 'C' screen.

[Magnate]

My point was that pricing isn't the big win from standardizing item power. The big win is being able to generate an item of arbitrary power and to measure the power of each item.

I agree. Pricing by power is nonetheless an improvement over the existing model, and is a lot easier to implement than generation by power! All in good time ...

There's a feature possiblity in here. More pval's per item.

Yeah, Sang has multiple pvals and it's great. Definitely an idea I hope Takkaria wants to implement at some point.

Speed (and every other factor) is dependant on where the character is.

Precisely. The desirability of any boon depends entirely on the situation - what depth, what other equipment, what class, etc. This is why we've taken what Pete called a "mean-field" approach, because it's impossible to take any other (except perhaps the two possibilities already described in this thread, both of which would require a lot of computational power and/or human effort).

I can take an approximation to how I'd write a power calculation formula if you want. I'll have to do a good bit of code study to understand how things impact performance as I don't have a perfect handle on everything.

Go for it. I'll be interested to see how it works.

Tangent: Some of the things that I think are poorly balanced with items tie into how items and power are distributed throughout the dungeon.

No objections to anything on your list. Interested in Takkaria's views.

CC

[Rizwan]

@Rizwan: rarity only affects pricing in the real world because it (artificially) alters desirability. The whole point of proposing power-based pricing is to base prices on desirability. So no, rarity isn't taken into account at all. If it were ever to do so, it would be based on overall attribute rarity (i.e. the chance of finding rnether), rather than base item rarity - because the former affects desirability and the latter doesn't.

So let me get this straight. A flail of westernesse is not more powerful because it is rare but it is more powerful because of the desirability of the combination of attributes that it has. BUT the combination of attributes is also rare. So in effect rarity does have an effect on power because the desirable attributes are not found commonly.

[Pete Mack]

@Rizwan-
that is exactly correct, and it is pretty ordinary economics. Everybody needs water, but it is (usually) very common and so is cheap.

In Angband pricing RBase is very similar: it is priced cheaply to allow it to pop up frequently on random artifacts. Alternatively, it is cheap because it is common. That doesn't mean it's not valuable; it's valuable like water is.