Rounding Error.

Trying to run Arctic Armour + Grace + 1 Blasphemy on a build I'm making.
Went to "Mikelat's Path of Exile Aura Calculator", to see what I could do, to achieve this without spending points. I DID! but...

When running an Alphas Howl and Conqueror's Efficiency the result is 100% Mana reservation.
When running level 3 enlighten and Conqueror's Efficiency the result is 101% Mana reservation.

So, I contacted Mikelat, he tested the setups in game, and got the same result.
His calculator was working correctly.

My question was why?
Answer. Rounding Error.

Some maths.

Alpha's Howl + Conqueror's Efficiency (no enlighten)
(50*0.9)= 45%
(35*0.9)= 32% (Rounded up from 31.5%)
(25*0.9)= 23% (Rounded up from 22.5%)
45+32+23= 100% (Mana Reservation as expected.)

Now , lets try Enlighten, gem by gem, followed by Conqueror's Efficiency.
Level 3 Enlighten Support + Conqueror's Efficiency (no Alpha's Howl).
(50*0.92)= 46%
(35*0.92)= 33% (Rounded up from 32.2%)
(25*0.92)= 23%
46+33+23= 102%
102*0.98= 99.96% (Calculated in this order, we'd expect it to still work.)

Lets try Conqueror's Efficiency first.
(50*0.98)= 49%
(35*0.98)= 35% (Rounded up from 34.3%)
(25*0.98)= 25% (Rounded up from 24.5%)
49+35+25= 109%
109*0.92= 100.28% (And we've broken the 100% barrier by 0.28%.)

Should this be altered? I think so. It's quite counter intuitive.
Also, I want my build to work.

:D

I think you have to take it gem by gem. You're combining some gems before applying multipliers. Like your last line says 109*.92. I don't think you can combine them to get 109 before multiplying by .92.

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mark1030 wrote:

I think you have to take it gem by gem. You're combining some gems before applying multipliers. Like your last line says 109*.92. I don't think you can combine them to get 109 before multiplying by .92.

This is correct. You should multiply each line by 0.98 *and* 0.92, then round up.

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dudiobugtron wrote:

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mark1030 wrote:

I think you have to take it gem by gem. You're combining some gems before applying multipliers. Like your last line says 109*.92. I don't think you can combine them to get 109 before multiplying by .92.

This is correct. You should multiply each line by 0.98 *and* 0.92, then round up.

any chance you both missunderstood what the OP wanted to say?

he pointed out that the game is exactly doing what he showed and he wants it to be canged.

or am i missing something? going through my standard stash to see myself would take me 1hour or so.

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Ruefl2x wrote:

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dudiobugtron wrote:

"

mark1030 wrote:

I think you have to take it gem by gem. You're combining some gems before applying multipliers. Like your last line says 109*.92. I don't think you can combine them to get 109 before multiplying by .92.

This is correct. You should multiply each line by 0.98 *and* 0.92, then round up.

any chance you both missunderstood what the OP wanted to say?

he pointed out that the game is exactly doing what he showed and he wants it to be canged.

or am i missing something? going through my standard stash to see myself would take me 1hour or so.

this.

"

Ruefl2x wrote:

any chance you both missunderstood what the OP wanted to say?

he pointed out that the game is exactly doing what he showed and he wants it to be canged.

or am i missing something? going through my standard stash to see myself would take me 1hour or so.

You are missing something. What you are missing is that the OP is wrong. The game is not doing what is described in the OP.

Like mark1030 said, this is what the game is actually doing with conqueror's efficiency and level 3 enlighten:

(50*0.92*0.98)= 46% (Rounded up from 45.08%)
(35*0.92*0.98)= 32% (Rounded up from 31.556%)
(25*0.92*0.98)= 23% (Rounded up from 22.54%)

46+32+23 = 101%. Just like the calculator says.

If you are getting a different result in game, please post screenshots showing the 3 aura tooltips, with the % they say they will reserve. Reservation and skill costs are worked out per skill.

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dudiobugtron wrote:

"

Ruefl2x wrote:

any chance you both missunderstood what the OP wanted to say?

he pointed out that the game is exactly doing what he showed and he wants it to be canged.

or am i missing something? going through my standard stash to see myself would take me 1hour or so.

You are missing something. What you are missing is that the OP is wrong. The game is not doing what is described in the OP.

Like mark1030 said, this is what the game is actually doing with conqueror's efficiency and level 3 enlighten:

(50*0.92*0.98)= 46% (Rounded up from 45.08%)
(35*0.92*0.98)= 32% (Rounded up from 31.556%)
(25*0.92*0.98)= 23% (Rounded up from 22.54%)

46+32+23 = 101%. Just like the calculator says.

If you are getting a different result in game, please post screenshots showing the 3 aura tooltips, with the % they say they will reserve. Reservation and skill costs are worked out per skill.

I said the calculator was correct.
I just didn't know exactly how it was getting there.
In fact your calculation makes the rounding error even more pronounced IMO.
The last few lines of my explanation (even if incorrect) was a measly 0.28% over.
Yours is only 0.08% over. That's nuts.

lol yes ofc now i see it!

you are right.

I agree it should be altered. I don't see a reason why reservation amounts need to be rounded to the nearest percent for each skill. It should keep the amount to like 1 or 2 decimal places, and then only round to the nearest mana point when working out the actual mana cost.

Ive run into simmilar rounding issues with RF as well. I think it has something to do with the numbers to % or something because ive had more than enough Regen to +max Fire res to susatin but still have slight degen but then simply changing some gear around to change my life EITHER way more or less will stop the degen completely if i have exactly enough figured for sustain. It would be the same i would think with mana since we are dealing with percentages.

So i would suggest trying this... Change some gear around to change the amount of mana you have. Keep track of weather its even or odd number as well since an odd number may be what is causing the rounding issue since an odd number sometimes wont go exactly into a percentage. if you get what im saying. Thats atleats what i think was causing some rounding issues ive had with RF having an odd number for life and changing my life to an even number seems to have fixed it before. But this also isnt always the case either. Ive did this before and still have degen. so. I only recently started using some of the calculators available for these figures and they seem to be spot on ive not run into rounding issues since i started using them.