# 1. How does Mr. Robot decide what optimizations to make?

It’s all about the math! Mr. Robot takes your stat weight and multiplies it by the amount of stat on the gem/enchant/reforge. For example, if you have Strength at a weight of 2, a gem with 160 Strength on it gets a score of 320. If you have Crit at a weight of 1.5, a gem with 320 Crit has a score of 480.

Let’s look at a real example: The stat weights for combat rogues are: Agility = 4, Haste = 2.2, and Expertise = 3.9. So at first, you might think it’s obvious that a 160 Agi gem should go in a red socket (socket bonus = 60 Expertise). But, not so quick! Let’s look at the math:

• 160 Agility Red Gem = 160 * 4 = 640
• 80 Agility & 160 Haste Orange Gem = (80 * 4) + (160 * 2.2) = 320 + 352 = 672
• 360 Haste Gem = (360 * 2.2) – (60 exp socket bonus * 3.9) = 792 – 234 = 558
• The winner is the hybrid gem – you get more out of it!

Cappable stats (like hit) have a weight up to the cap, then their value is 0 after the cap. So let’s say you need 300 hit rating to get to the cap. Let’s also say your weight for hit is 1.2. A +320 hit gem would be calculated as follows: (300 * 1.2) + (20 * 0) = 360. As you can see, Mr. Robot didn’t give points to the extra 20 hit, since it would put you over the hit cap, but the rest of the hit rating did get a score.

Since he optimizes everything – he can look at a lot of combinations and move stats between gems, enchants and reforges. This becomes particularly important now that secondary stat gems have twice the value as primary gems (160 Strength vs 320 Hit). So now it’s possible that a secondary stat gem, or a hybrid gem, end up being the best option.

Mr. Robot is programmed to get you the highest possible score. It’s that simple!

# 2. Why Mr. Robot sometimes puts you under the hit cap?

Mr. Robot wants to get you the highest score (which translates into the highest DPS for damagers, damage mitigation for tanks, etc). It’s easy to agree that any hit rating over the cap is wasted. But what isn’t as obvious is that getting exactly to the hit cap isn’t always the best option (sometimes it is, but often times it is not).

Let’s use an example to understand this better. Let’s say +Hit is your highest weighted stat with a weight of 2. Let’s say Crit has a rating of 1.8 and Mastery 1.2. The thing to focus on in this example is that Crit is much more valuable than Mastery, AND there are a finite number of combinations to get you to an exact number. On to the example: it’s possible that to get you exactly to the hit cap, you’d have to reforge all of your Crit to Hit. BUT!!! Let’s say you can get to within 20 Hit rating of the cap but you preserve all of your Crit, and instead reforge all of your mastery – since Mastery is much less valuable that crit. Your final score would be higher. Here are some made up numbers as an example:

To get exactly hit capped:
Lose 600 Crit:   -1080
Gain 600 Hit (get exactly to cap): +1200
Total Score change: +120

To get within 20 of hit cap:
Lose 580 Mastery:  -696
Gain 580 Hit (20 below hit cap):  +1160
Total Score change: +464

A lot of people ask why they can’t change the hit cap in his optimizer. That’s because there is no reason to change the cap. He lets you change modes – raid, 5 man, challenge mode, pvp. Changing the mode changes the hit cap, but he still won’t let you manually edit the caps. There’s no need to   You can change the weights though, as much as you want!

# 3. Where does Mr. Robot get his stat weights?

We wrote a program the interfaces with SimC. It runs through all sorts of sets of gear until it converges on a stable set of stat weights. We then review those weights to make sure they make sense, in case there’s a bug or bad assumptions in any of the programs. We also then work with a lot of theorycrafters to get their feedback and make sure the weights make sense.

That being said, everything is still being tweaked. For example, there will soon be a big update for a couple Monks in SimC, so we’ll run new simulations when that happens. We’re also watching how people play and raid, to see if Mastery is more important for a lock than Haste.

Mr. Robot is all about the math. So you can count on us to continuously check on weights, assumptions, run more SimC trials, and use our human brains (which can sometimes be better than computers, but don’t tell that to Mr. Robot… his head might explode).

And of course, you can always put in your own stat weights! You can also test things out for yourself with SimC. If you click the export button on the action bar, you’ll see an option to export the results to SimC. Mr. Robot doesn’t hide anything, he wants you to be able to compare results!

# 4. Mr. Robot takes into account your racials, professions, etc.

Mr. Robot knows every racial bonus,  profession bonus, etc. He factors this is when optimizing your gear – so don’t worry, he won’t accidentally forget and put you over the caps.

When looking at professions, he knows that if you’re a Jewelcrafter, he can suggest special JC gems. If you are not a Jewelcrafter, he won’t suggest them. If you want to change your profession to see how it would affect your gear, you can do that. Open the options window. At the bottom you’ll see the different professions, go ahead and change them.

# 5. Mr. Robot’s BiS lists are dynamically generated

The BiS list you see might be different than the one from your favorite blogger, or different from the guildmate you raid with. This is because Mr. Robot suggests a BiS list tailored to YOU and YOUR PREFERENCES! Did you know… based on the options from Mr. Robot, all the classes and specs, there are over a billion different possible BiS lists? We cache about 25 million of the most popular BiS lists, so they load fast for Mr. Robot’s visitors. If you have one not in the cache, no worries, it still loads fast, just not AS fast.

Let’s look at some examples:  if you have 1% Expertise for being a human, well, that might affect the best gear for you – perhaps you need less expertise on your gear, or a piece with different reforge options. Also, when you change options, like ‘exclude valor point gear,’ Mr. Robot will go through the list again and adjust it. Changing stat weights also means you’ll get a different set of gear. That’s the beauty of it – the BiS list is tailored to what YOU want.

Below is an example from my Resto Druid. I selected “Pre Raid” gear, then changed a few more settings along the way. You can see how that affects my BiS list.

• Willawonka

This optimizer is not working for me at all. I’m an Arcane mage and it’s telling me I need Expertise. -__- I KNOW I don’t use that. Please I would love it for this to work it was so awesome before. =(

• Krazyito

Well, when MoP released, one point of Expertise = one point of Hit. So Mr. Robot is indeed correct.

• Vivimord

Indeed, what Krazyito said. Expertise now functions as hit for casters. Which means you can reforge for expertise on gear that already has hit on it, making it even easier to reach the hit cap if you’re struggling.

Expertise is now used by mages to up there spell hit use it trust me i am a frost mage doing sick amounts of damage now with it.

• Zeam

That’s a bad example for orange gems in a red socket because expertise has a cap. So it’s not sacrificing agility for expertise, it’s sacrificing agility for the crit, mastery, and haste that would have been reforged into expertise.

• Gnomethan

The optimizer is telling me reforge for hit and exp that is putting me way over the hit cap.

• Xara

Caster hit cap is now 15% in MOP, robot is taking it to 17% why?

• Goez

I am having the same problem with the optimizer telling me to reforge for hit and exp which puts me over cap as well. Another thing I noticed is that it shows my mastery 10% over where it actually is and my crit 3% under my current total. Any help would be greatly appreciated in figuring out what is the problem.

• zoopercat

Sorry for the slow reply – I missed this comment some how. Can you give me your character name and realm so I can see what’s happening and why? Thanks

• Goez

Subject: [askmrrobot] Re: How Does Mr. Robot’s Optimizer Work?

• Darth Nuts

Reason’s for allowing us to set our own hit cap.

A. We may raid with a Draenei and therefore get to benefit from their 1% racial bonus to hit

B. As a Gnome, my 1% expertise racial only takes account when I have a sword or dagger equipped, and maybe I want to play “what if” even though I am currently sporting a staff.
C. Maybe I like to eat +300 Expertise food when in a raid, that way when I am in a dungeon/questing I get benefit from the extra stats, rather than have +hit go to waste.

• minstrel

Draenei racial bonus is self-only. It was changed at the start of Cataclysm to not affect party/raid members.

• Darth Nuts

Okay, so what about the use of +300 hit food?

• Math_Geek

I understand the fitness function, but isn’t the gemming, reforging, and enchanting optimization akin to the knapsack problem, and thus NP-hard? How do you do it so quickly? Is the space small enough that you just memoize the permuntations?

Anyway thanks for your hard work.

• Valros

Yes the knapsack problem is NP-hard, but can still be solved on modern computers quickly by just brute-forcing it if the number of permutations is relatively small, which I’m guessing is the case here.

• Liane

I do not understand why I as elemental shaman shall take spirit flask? doenst it make more sense to reforge to the hit cap an use int-flasks?

• Romin

I would say no Spirit is the best way to flask because it increases hit as well as mana regen, while int increases output. If you run out of mana however there is 0 output. That is my thought I have no numbers to back it.

• Romin

I don’t understand where you are getting your Haste numbers on my Shaman. In game it says I am 11.85% spell haste given by 2,771(+6.52 haste) and 5% from a talent. The optimizer has me at 13.09% haste and is telling me to reforge out of haste into master due to being above the 12.51% haste level.

• Erynnchan

Why is Mr. Robot recommending a strength enchant for a feral druid?

I have been contemplating that fact for quite a while, and as usual when u have made a post about the topic u check around a bit more and notice the ranking option “absolute” and “relative” which explains it..

The fact I was refering to was that in terms of “absolute” ranking a normal 489 raid weapon (Mogu’shan Vaults) for hunters was better than a 483 LFR weapon (Terrace of Endless Spring) despite the legendary +500 agi sha-touched socket. In “relative” however the LFR weapon was slightly better.

• Cruzan

Is there a way to bring the hard cap for hit down to .14 from .15? As a gnome using a dagger it would be extremely handy to be able to switch this in the options or custom weights. The FAQ mentions that racials are taken in to account, but the optimizer is still trying to keep me at 15%.

• zoopercat

When Mr. Robot gets you to 15%, he’s adding in your racial. So he’s getting you to 14% on your gear, then adding 1% for your racial to end at 15%. Is that what you are looking for? Or is something still wrong?

• Cruzan

Okay that makes sense! Thanks

• Hawkeye612

So you say you get close to the cap which I completely understand, but when I used it today it recommended droppign me from a bit over to almost 4% under. That’s not even close.

• Jesper Bødtcher

Hi

As Goez has stated “Another thing I noticed is that it shows my mastery 10% over where it actually is and my crit 3% under my current total”

Im experiencing the same issue with Mastery showing ~ 16% higher than it is, the crit is showing 2% lower. Why is that?

• zoopercat

Is your character level 90? There are different mastery coefficients for each level – we only use the level 90 ones

• Jesper Bødtcher

The character is already lvl 90

• zoopercat

Can you give me your character name and realm? I’ll dig into the mastery?

Crit is correct: you get a 5% raid buff, but a 3% ‘debuff’ when fighting a boss. So we should show you 2% higher, and that’s on purpose – it’s what you would have when fighting a boss.

• Jesper Bødtcher

Nvm, ive found out that the 16% more was supposed to be comming from buff.

Maybe that shouldnt be enabled when doing Reforging/Gemming/Enchanting calculations?

• zoopercat

Hey, I caught this after my reply, oops! Yeah, we assume full raid buffs. We might add in a feature that lets people select their raid buffs.