Level Correction Function and pDIF

From FFXIclopedia, the free Final Fantasy XI encyclopedia

Contents 1 The Level Correction function 2 pDIF 2.1 Melee Attack 2.2 Melee pDIF characteristic 2.3 Updated PDIF Formulas 2.4 1-Handers 2.5 2-Handers 2.6 Ranged Attack 3 Notes 4 See also

The Level Correction function

The Level Correction function modifies your (ranged) attack / monster defense ratio before it is used in the pDIF function.
Let's say you have 400 attack / ranged attack and the monster has 400 defense. Your (r)atk/def ratio would then be 1.
If the monster has a higher level than you, then a level corrected ratio is needed before calculating the pDIF.
Otherwise, when fighting EM monsters or lower, your atk/def ratio will not be modified when used in the pDIF function. In other words, there is no level correction.

For this example, assume you are fighting a level 81 monster and your own character is level 75.
Let Ratio be the value of your (r)atk divided by monster defense.
Ratio = your (r)atk/monster defense
Melee cRatio = Ratio - 0.050 x level difference
Ranged cRatio = Ratio - 0.025 x level difference

So after the level correction, your melee attack ratio is 0.7 and your Ranged Attack ratio is 0.85.

The min and max value of pDIF is the lower bound and upper bound of damage fluctuation.

pDIF

The pDIF calculation takes your (level corrected) Attack and Defense ratio and outputs a random number in certain value range.
pDIF always has a positive value.

• One Handers, Two Handers and Ranged pDIF have different formulas:

Melee Attack

Note: The following equations are no longer correct. Research is currently being done (as of 25/08/2009) to determine the new equations. These will be kept on the wiki until the correct set of formulas has been discovered.

max pDIF has the following formulas:

Ratio Range	Function Value
0 ≤ cRatio < 0.5	fMax(cRatio) = 0.4 + 1.2 x cRatio
0.5 ≤ cRatio ≤ 5/6	fMax(cRatio) = 1
5/6 < cRatio ≤ 2	fMax(cRatio) = 1.2 x cRatio

and Min pDIF has the following formulas:

Ratio Range	Function Value
0 ≤ cRatio < 1.25	fMin(cRatio) = -0.5 + 1.2 x cRatio if fMin < 0 → fMin = 0
1.25 ≤ cRatio ≤ 1.5	fMin(cRatio) = 1
1.5 < cRatio ≤ 2	fMin(cRatio) = -0.8 + 1.2 x cRatio

• When cRatio exceeds 2.0, cRatio is 2.0 (capped for melee)
• Rules for melee Critical Hit

When critical hit occurs, your pDIF will be raised by 1 and the max pDIF cap is 3.0 instead of 2.4.

Examples:

When your pDIF is 0.4 and you score a critical hit, your pDIF is raised to 1.4 (add 1.0 to current pDIF value)

When your pDIF is 2.3 and you score a critical hit, your pDIF is raised to 3.0 (3.3 → 3.0, since 3.0 is the cap)

When your pDIF is -0.4 and you score a critical hit, your pDIF is raised to 0.6, but your normal attack will have pDIF = 0 (pDIF lower bound is 0)

Melee pDIF characteristic

When you have pDIF_min≤1.0 AND pDIF_max ≥1.0, the mode of pDIF lies on 1.0 about 33%±7% of the time.

Updated PDIF Formulas

• The formula for PDIF varies for 1H and 2Hers and/or the cRatio cap varies.

1-Handers

See Discussion Page.

max pDIF has the following formulas:

Ratio Range	Function Value
0 ≤ cRatio < 0.5	fMax(cRatio) = 0.4 + 1.2 x cRatio
0.5 ≤ cRatio ≤ 5/6	fMax(cRatio) = 1
5/6 < cRatio ≤ 1.99	fMax(cRatio) = 1.2 x cRatio
2 (capped)	fMax(cRatio) = 1.2 x cRatio + 0.05 (Proven)

and Min pDIF has the following formulas:

Ratio Range	Function Value
0 ≤ cRatio < 1.25	fMin(cRatio) = -0.5 + 1.2 x cRatio if fMin < 0 → fMin = 0
1.25 ≤ cRatio ≤ 1.5	fMin(cRatio) = 1
1.5 < cRatio ≤ 1.99	fMin(cRatio) = -0.8 + 1.2 x cRatio
2 (capped)	fMin(cRatio) = 1.2 x cRatio - 0.82 (Proven)

2-Handers

max pDIF has the following formulas:

Ratio Range	Function Value
0 ≤ cRatio < 0.5	fMax(cRatio) = 0.4 + 1.2 x cRatio
0.5 ≤ cRatio ≤ 5/6	fMax(cRatio) = 1
5/6 < cRatio ≤ 2	fMax(cRatio) = 1.2 x cRatio

and Min pDIF has the following formulas:

Ratio Range	Function Value
0 ≤ cRatio < 1.25	fMin(cRatio) = -0.5 + 1.2 x cRatio if fMin < 0 → fMin = 0
1.25 ≤ cRatio ≤ 1.5	fMin(cRatio) = 1
1.5 < cRatio ≤ 2	fMin(cRatio) = -0.8 + 1.2 x cRatio

Ranged Attack

Ratio Range	Function Value
0 ≤ cRatio < 0.9	fMax(cRatio) = 10/9 x cRatio
0.9 ≤ cRatio ≤ 1.1	fMax(cRatio) = 1
1.1 < cRatio ≤ 3.0	fMax(cRatio) = cRatio

Ratio Range	Function Value
0 ≤ cRatio < 0.9	fMin(cRatio) = cRatio
0.9 ≤ cRatio ≤ 1.1	fMin(cRatio) = 1
1.1 < cRatio ≤ 3.0	fMin(cRatio) = -3/19 + 20/19 x cRatio

• When cRatio exceeds 3.0, cRatio is 3.0 (capped for ranged)

• Rules for ranged Critical Hit

Ranged critical hit always multiplies your pDIF by 1.25

Example:

When your pDIF is 3.0 and you score a critical hit, your pDIF will be 3.75

Notes

It seems that ratio, cRatio, and pDIF values are truncated to 3 digits.

See also

• Calculating Weapon Skill Damage
• Base Damage