AtrMove, BaseCohLoss, BaseAttrition

[Jagger]

I have updated the models in the PBEM mod to match the new format for 1.10.

I am curious about how the three new data fields, (AtrMove, BaseCohLoss and BaseAttrition) function.

I assume there is still some attrition now while moving with AtrMove. Is it connected to cohesion or independent? I assume a larger number increases attrition due to cohesion loss?

I am assuming the BaseAttrition is attrition independent of movement. All infantry is using a base attrition of 22. Does this mean units have 22% chance of attrition per turn? How does base attrition work?

Previously, Units used CohMove to determine cohesion loss during movement. Is BaseCohLoss related to attrition or cohesion loss during movement. How does it impact attrition or cohesion loss?

Any help appreciated.

[Primasprit]

The main goal of the change in the calculations for the attrition and the cohesion loss was to make both effects fully independent from each other.
Every Model has 2 parameters which determine the attrition and 2 parameters for the calculation of the cohesion loss.
There are two different kinds of Attrition/Cohesion loss: First the Attrition/Cohesion loss while moving. Secondly an additional base Attrition/Cohesion loss, which applies no matter if the units are moving or not. This additional effect is only applied if the rule 'Historical Attrition' is enabled.


Attrition:

AtrMove
Base value of Health points lost per day while moving.
[font="Franklin Gothic Medium"](Health lost) = AtrMove * (Health points of the Element) / 10000[/font]

Example:
AtrMove = 100
Health of Element = 20
--> The element will lose 0.2 Health per day.
The health value used for the calculation is the current health, not the maximum health.


BaseAttrition
Base value of Health points lost per day (even if not moving). These attrition is only present with the game rule 'Historical Attrition' enabled and is applied additionally to the attrition due to movement.
[font="Franklin Gothic Medium"](Health lost) = BaseAttrition * (Health points of the Element) / 10000[/font]

Example:
BaseAttrition = 22
Health of Element = 20
--> The element will lose 0.044 Health per day.


Cohesion:

CohMove
Base value of Cohesion lost per day while moving.
[font="Franklin Gothic Medium"](CohesionLoss) = CohMove / 100[/font]

Example:
CohMove = 100
--> The element will lose 1 Cohesion point per day.


BaseCohLoss
Base value of Cohesion points lost per day if the rule “Historical Attrition” is enabled.
[font="Franklin Gothic Medium"](CohesionLoss) = CohBaseLoss / 100[/font]

Example:
CohBaseLoss = 22
--> The element will lose 0.22 Cohesion per day.


The base values for the Attrition and the Cohesion loss are modified with several coefficients. These coefficients describe the impact of the weather, terrain, military control, loyalty, and so on. The variables are exported in the file [font="Courier New"]Cohesion&Attrition.opt[/font].

To calculate the resulting Attrition/Cohesion loss, the coefficients are added and modify the Attrition/Cohesion loss according to this equation:

[font="Franklin Gothic Medium"]Attrition = AttritionBaseValue + AttritionBaseValue * AttritionCoefficient
CohesionLoss = CohesionLossBaseValue + CohesionLossBaseValue * CohesionLossCoefficient[/font]

(AttritionBaseValue and CohesionLossBaseValue are the values directly calculated from the entries in the model file.)


An example will follow soon...

[Primasprit]

Example: Normal Attrition rules

An infantry Element is walking through the countryside.
It has the model parameters:
[font="Franklin Gothic Medium"]
Hits = 20
CohMove = 100
AtrMove = 100
BaseCohLoss = 22
BaseAttrition = 22[/font]

With the standard attrition rules we only have to care about these model parameters:

[font="Franklin Gothic Medium"]Hits = 20
CohMove = 100
AtrMove = 100[/font]

Reason: Elements will only lose cohesion and suffer from attrition if they move.

So, what does these numbers tell:

CohMove describes the number of cohesion points divided by 100 an Element loses per day. Only if it is moving of course.
CohMove = 100 --> The element will lose 1 cohesion point per day.

AtrMove describes the number of health points an Element is losing per day. The calculation is different from the one of the cohesion loss however. The number of health points a unit loses is calculated by: AtrMove multiplied with the current number of health points the Element posses and divided by 10000. The infantry element has, if it is at full health, 20 health points.
So it will lose [font="Franklin Gothic Medium"]100 * 20 / 10000 = 0.2[/font] health points per day. If the unit has already lost some health, maybe from a fight, and has only 10 health points left it will also lose less health per day due to attrition: [font="Franklin Gothic Medium"]100 * 10 / 10000 = 0.1[/font] health points per day.

Let's assume the infantry element walks on a road, in an offensive posture, through snow conditions and in a region there the faction the infantry element belongs to has 30% military control.

The coefficients from the opt files which are interesting now are:

[font="Franklin Gothic Medium"]cohMoveCoeffHarsh = 200
cohMoveCoeffOffense = 25
cohMoveCoeffRoad = -30
cohMoveCoeffMilContr = 150

atrMoveCoeffHarsh = 200
atrMoveCoeffRoad = -30
atrMoveCoeffMilContr = 150[/font]


These values do modify the base values CohMove and AtrMove.
At first lets take a look to the Cohesion:
The modifiers are simply added:
[font="Franklin Gothic Medium"]
TotalCohesionCoeff = cohMoveCoeffHarsh + cohMoveCoeffOffense + cohMoveCoeffRoad + cohMoveCoeffMilContr
TotalCohesionCoeff = 100 + 25 - 30 + 105 = 200[/font]

So, where does the '105' come from? It is the parameter [font="Franklin Gothic Medium"]atrMoveCoeffMilContr = 150[/font]. We assumed that the faction our infantry Element belongs to has 30% military control in the region. This means the enemy has 70% control.
[font="Franklin Gothic Medium"]cohMoveCoeffMilContr * 70% = 150 * 0.7 = 105[/font]

A note to the effect of the weather: Weather can be 'not harsh', 'harsh' and 'very harsh'. Which weather ('Frozen', 'Snow' ...) is in a certain terrain ('Wood', 'Clear' ...) treated as harsh, is defined in the terrain DB. Each terrain has for each weather two harshness levels. One influence the Attrition and one the Cohesion.

OK, as calculated above the TotalCohesionCoeff is 200. This simply means that the CohMove parameter of the infantry Element is modified by 200%.

[font="Franklin Gothic Medium"]TotalCohMove = CohMove + CohMove * TotalCohesionCoeff / 100
TotalCohMove = 100 + 100 * 200% = 300[/font]

So the coefficients from the opt files simply added 200% to the CohMove of the Element.
As said before: CohMove describes the number of cohesion points divided by 100 an Element loses per day. So the infantry element loses now 3 cohesion points per day.

For attrition it is the same. The interesting parameters are:

[font="Franklin Gothic Medium"]atrMoveCoeffHarsh = 100
atrMoveCoeffRoad = -30
atrMoveCoeffMilContr = 150

TotalAttritionCoeff = atrMoveCoeffSnow + atrMoveCoeffRoad + atrMoveCoeffMilContr
TotalAttritionCoeff = 100 - 30 + 105 = 175

TotalAtrMove = AtrMove + AtrMove * TotalAtrCoeff / 100
TotalAtrMove = 100 + 100 * 175% = 275[/font]

With an current health of 20 the Element will lose
[font="Franklin Gothic Medium"]275 * 20 / 10000 = 0.55[/font] health points per day.

[Primasprit]

2. Example: Historical Attrition rules

The Historical Attrition rule does not modify in any way the Cohesion loss and Attrition while moving. The Historical Attrition rule applies an additional Attrition/Cohesion loss. This Attrition/Cohesion loss does not depend on the fact if a unit move or not. It is a base Attrition/Cohesion loss which applies always. Please note also that the rules which describe the regain of Cohesion and Health (if a unit is resting) is also independent of the Historical Attrition rule. So even if the Historical Attrition rule is on, a unit can regain Cohesion while resting in a region.

An infantry Element has these model parameters:
[font="Franklin Gothic Medium"]
Hits = 20
CohMove = 100
AtrMove = 100
BaseCohLoss = 22
BaseAttrition = 22[/font]

The interesting values in the model file are:

[font="Franklin Gothic Medium"]Hits = 20
BaseCohLoss = 22
BaseAttrition = 22[/font]

So if the element is doing nothing at all it will lose
[font="Franklin Gothic Medium"]22 / 100 = 0.22[/font] cohesion points per day and
[font="Franklin Gothic Medium"]22 * 20 / 10000 = 0.044[/font] health points per day.

Here the parameter in the opt file which influence the Historical Attrition

[font="Franklin Gothic Medium"]cohHarshWeaMod = 80
cohVHarshWeaMod = 160
cohCityScapeMod = -144
cohPillagedMod = 64
cohLoyaltyMod = -64 // For 100% Loyalty, linear scaled if loyalty smaller.
cohScorchedEarthMod = 32

atrHarshWeaMod = 80
atrVHarshWeaMod = 160
atrCityScapeMod = -144
atrPillagedMod = 64
atrLoyaltyMod = -64
atrScorchedEarthMod = 32[/font]


The calculation of the effects of the coefficients is the same as the calculation for the attrition/cohesion loss if a unit is moving.


Example 1:

The infantry element is in a region with a city, blizzard, 100% loyalty.

[font="Franklin Gothic Medium"]TotalCohesionCoeff = cohVHarshWeaMod + cohCityScapeMod + cohLoyaltyMod
TotalAttritionCoeff = atrVHarshWeaMod + atrCityScapeMod + atrLoyaltyMod

TotalCohesionCoeff = 160 - 144 - 64 = -48
TotalAttritionCoeff = 160 - 144 - 64 = -48

TotalBaseCohLoss = BaseCohLoss + BaseCohLoss * TotalCohesionCoeff / 100
TotalBaseCohLoss = 22 - 22 * 48% = 11 (rounded value)
TotalBaseAttrition = BaseAttrition + BaseAttrition * TotalAttritionCoeff / 100
TotalBaseAttrition = 22 - 22 * 48% = 11 (rounded value)[/font]

The Element will lose
[font="Franklin Gothic Medium"]11 / 100 = 0.11[/font] cohesion points per day.
With an current health of 20 the Element will lose
[font="Franklin Gothic Medium"]11 * 20 / 10000 = 0.022[/font] health points per day.

Again: The attrition/cohesion loss is independent from the recovery rate! So in this case the recovery rate is only slightly reduced, the Element will not really lose cohesion.


Example 2:

The infantry element is in a region with a without a city, snow, 50% loyalty, region pillaged.
[font="Franklin Gothic Medium"]
TotalCohesionCoeff = cohHarshWeaMod + cohLoyaltyMod + cohPillagedMod
TotalAttritionCoeff = cohHarshWeaMod + atrLoyaltyMod + atrPillagedMod

TotalCohesionCoeff = 80 - 32 + 64 = 112
TotalAttritionCoeff = 80 - 32 + 64 = 112

TotalBaseCohLoss = BaseCohLoss + BaseCohLoss * TotalCohesionCoeff / 100
TotalBaseCohLoss = 22 + 22 * 112% = 47 (rounded value)
TotalBaseAttrition = BaseAttrition + BaseAttrition * TotalAttritionCoeff / 100
TotalBaseAttrition = 22 + 22 * 112% = 47 (rounded value)[/font]

The Element will lose
[font="Franklin Gothic Medium"]47 / 100 = 0.47[/font] cohesion points per day.
With an current health of 20 the Element will lose
[font="Franklin Gothic Medium"]47 * 20 / 10000 = 0.094[/font] health points per day.


Example 3:

The infantry element is moving in a region without a city, snow, 50% loyalty, region pillaged, road, offensive posture, 30% military control. After 7 days the Element reaches it's destination and is not moving for the remaining 7 days of the turn.

In my previous post I calculated the attrition/cohesion loss for a moving element under these conditions:

[font="Franklin Gothic Medium"]TotalCohMove = 100 + 100 * 200% = 300
TotalAtrMove = 100 + 100 * 175% = 275[/font]
The element lose 3 cohesion points and 0.55 health points per day.
It moves 7 days:
21 cohesion points lost, 4 (3.85) health points lost.

Additionally the Historical attrition rule applies:
In example 2 I calculated the attrition/cohesion loss: The Element will lose 0.47 cohesion points per day and 0.094 health points per day.
If 1 turn = 14 days: 7 (6.58) cohesion points lost and 1 (1.316) health point lost.

So the element will lose altogether:
[font="Franklin Gothic Medium"]21 + 7 = 28[/font] cohesion points and
[font="Franklin Gothic Medium"]4 + 1 = 5[/font] health points.

[Jagger]

Primaspirit, I hope you are a teacher or instructor or professor. This is a superb explanation!!

Tonight, I am going to absorb all this information. I may have follow-up questions but at first glance, it appears all my questions are answered.

Thanks again!

[Jagger]

A couple follow-up questions

Is the base value of health points always 20 for all units or is it directly linked to the number of unit hits?

To determine actual attrition loss of men, is the the loss of 1 health point equivalent to the loss of one man?

Thanks again!

[Primasprit]

Is the base value of health points always 20 for all units or is it directly linked to the number of unit hits?

'Health Points' and 'Hits' are only different words for the same thing.

To determine actual attrition loss of men, is the the loss of 1 health point equivalent to the loss of one man?

The parameters 'MenPerHit', 'GunsPerHit' and 'HorsesPerHit' are the conversation factors for Hits into the number of men. Additionally a slight random fluctuation is added.

The game itself uses only the 'Hits' for it's calculations. Never the 'real' number of men. This number is only used for the display on the interface. So if you tweak the attrition and want to check the effects, look for the number of Hits, not the number of Men/Horses/Guns.

Cheers
Norbert

[Jagger]

'Health Points' and 'Hits' are only different words for the same thing.


The parameters 'MenPerHit', 'GunsPerHit' and 'HorsesPerHit' are the conversation factors for Hits into the number of men. Additionally a slight random fluctuation is added.

The game itself uses only the 'Hits' for it's calculations. Never the 'real' number of men. This number is only used for the display on the interface. So if you tweak the attrition and want to check the effects, look for the number of Hits, not the number of Men/Horses/Guns.

Cheers
Norbert

Ok that makes sense. I assume since health points are often a percentage that a percentage chance exists for a hit. Do you know if hits are calculated each day or if a single cumulative hit check is made? I assume hits are checked each day.

The system looks very good. I would be nice to have a attrition variable available for unhealthy terrain such as swamps/marsh during warm weather. Something inherent to certain types of terrain.

I did some quick calculations focused on historical attrition to get a feel for some typical situations. Here are the results.

Example One: Raised a brand new conscript regiment in a city with 100% loyalty, good weather and no movement.

TotalAttritionCoeff = atrCityScapeMod + atrLoyaltyMod

TotalAttritionCoeff = -144-64=-208

TotalBaseAttrition = BaseAttrition + BaseAttrition * TotalAttritionCoeff / 100
TotalBaseAttrition = 22 - (22 * 208%)/100) = 22-45.76=-24 (rounded value)

Note, I assume since the TotalAttritionCoeff is a negative number, the (BaseAttrition * TotalAttritionCoeff / 100) is subtracted instead of added to the BaseAttrition value.

By subtracting, the final result is a negative number and thus no health points are lost.

------------------------------------------

Example Two: Same as before except add blizzard conditions.

Example: Raised a brand new conscript regiment in a city with 100% loyalty, blizzard and no movement.

TotalAttritionCoeff = atrCityScapeMod + atrLoyaltyMod + atrHarshWeaMod

TotalAttritionCoeff = -144-64+160=-48

TotalBaseAttrition = BaseAttrition + BaseAttrition * TotalAttritionCoeff / 100
TotalBaseAttrition = 22 - (22 * 48%)/100) = 22-10.56= 11 (rounded value)

Note, I assume since the TotalAttritionCoeff is a negative number, the (BaseAttrition * TotalAttritionCoeff / 100) is subtracted instead of added to the BaseAttrition value.

So with an current health of 20 the Element will lose
11 * 20 / 10000 = 0.022 health points per day or .33 health points over 15 day turn.

---------------------------------------------------

Example Three: Same conscript regiment stationary in clear terrain without city, 100% loyalty, no pillaging, good weather and no movement.

TotalAttritionCoeff = atrLoyaltyMod

TotalAttritionCoeff = -64=-64

TotalBaseAttrition = BaseAttrition + BaseAttrition * TotalAttritionCoeff / 100
TotalBaseAttrition = 22 - (22 * 64%)/100) = 22-14.08= 8 (rounded value)

Note, I assume since the TotalAttritionCoeff is a negative number, the (BaseAttrition * TotalAttritionCoeff / 100) is subtracted instead of added to the BaseAttrition value.

So with an current health of 20 the Element will lose
8 * 20 / 10000 = 0.016 health points per day or .24 health points over 15 day turn.

---------------------------------------------------

Example Four: Same conscript regiment stationary in clear terrain without city, 100% loyalty, no pillaging, with harsh weather and no movement.

TotalAttritionCoeff = atrLoyaltyMod+atrHarshWeaMod

TotalAttritionCoeff = -64+80=+16

TotalBaseAttrition = BaseAttrition + BaseAttrition * TotalAttritionCoeff / 100
TotalBaseAttrition = 22 + (22 * 16%)/100) = 22+3.52= 26 (rounded value)

Note, formula remains the same as the TotalAttritionCoeff is a positive number.

With an current health of 20 the Element will lose
26 * 20 / 10000 = 0.052 health points per day or .78 health points over 15 day turn.

[Jagger]

So if hits are calculated daily, then in the last example using .052 health points, the total percentage chance of suffering a hit in clear terrain and harsh weather over 15 days would be:

1-(.948)15th power= 55%

So in a regiment of 1000 men with 20 hits at 50 men per hit, then a total 55% chance over 15 days of suffering one hit and losing 50 men from the regiment in open terrain and harsh weather. Although an unlucky regiment could suffer more than one hit if hits are calculated daily.

If a division of 12 regiments of 12,000 men, then expect to suffer approximately 6 hits or lose approximately 300 men for a 2.5% attrition rate.

[Primasprit]

Do you know if hits are calculated each day or if a single cumulative hit check is made? I assume hits are checked each day.

The Attrition due to movement is checked daily. The additional attrition for the game rule 'Historical Attrition' is checked per turn.
The decimal fractions are rounded up or down with the correct probability.

The system looks very good. I would be nice to have a attrition variable available for unhealthy terrain such as swamps/marsh during warm weather. Something inherent to certain types of terrain.

This can be done. You can define in the terrain DB for each weather if the effects should be harsh, very harsh or not harsh.
While in clear terrain, for warm weather, the effect on cohesion and attrition would be defined as 'not harsh', in a swamp terrain the effect on cohesion might be defined as 'very harsh' and the effect on attrition as 'harsh' (only as an example).

(Remark: The numbers I used for my examples above, are different from the ones used in AACW right now. They were heavily tweaked by the ACW experts of the Beta group. )

[Jagger]

The Attrition due to movement is checked daily. The additional attrition for the game rule 'Historical Attrition' is checked per turn.
The decimal fractions are rounded up or down with the correct probability.

It is odd that "Historical Attrition" is checked per turn rather than daily. A player could hop from city to city and never suffer historical attrition. That loophole could be abused. Also will benefit the more stationary and defending CSA player.

This can be done. You can define in the terrain DB for each weather if the effects should be harsh, very harsh or not harsh.
While in clear terrain, for warm weather, the effect on cohesion and attrition would be defined as 'not harsh', in a swamp terrain the effect on cohesion might be defined as 'very harsh' and the effect on attrition as 'harsh' (only as an example).

(Remark: The numbers I used for my examples above, are different from the ones used in AACW right now. They were heavily tweaked by the ACW experts of the Beta group. )

Good idea!

[lodilefty]

So if hits are calculated daily, then in the last example using .052 health points, the total percentage chance of suffering a hit in clear terrain and harsh weather over 15 days would be:

1-(.948)15th power= 55%

So in a regiment of 1000 men with 20 hits at 50 men per hit, then a total 55% chance over 15 days of suffering one hit and losing 50 men from the regiment in open terrain and harsh weather. Although an unlucky regiment could suffer more than one hit if hits are calculated daily.

If a division of 12 regiments of 12,000 men, then expect to suffer approximately 6 hits or lose approximately 300 men for a 2.5% attrition rate.

Maybe I'm dense, but I interpreted this as 'hits', not the 'probability of a hit'.

[Jagger]

Maybe I'm dense, but I interpreted this as 'hits', not the 'probability of a hit'.

Units can only suffer losses as hits. So a minimum loss for a typical regiment would be a single hit of 50 men. I don't believe you can get partial hits.

So I am assuming the numbers are percentage chances of a complete single hit.

[lodilefty]

Units can only suffer losses as hits. So a minimum loss for a typical regiment would be a single hit of 50 men. I don't believe you can get partial hits.

So I am assuming the numbers are percentage chances of a complete single hit.

I got my inference from post #4, where days * the number is reported as total hits.....

so you've successfully confused me....

[Jagger]

I got my inference from post #4, where days * the number is reported as total hits.....

so you've successfully confused me....

I think we are going to have to wait till Primaspirit can clarify.

[lodilefty]

I think we are going to have to wait till Primaspirit can clarify.

So now we can be confused together?

I usually have this effect on people.....

[Primasprit]

Partial hits are not possible. If, for example, the attrition calculates to 1.36 hits per turn, the element takes 1 hit for sure and take a second hit with a probability of 36%.

Cheers
Norbert

[Primasprit]

It is odd that "Historical Attrition" is checked per turn rather than daily. A player could hop from city to city and never suffer historical attrition. That loophole could be abused. [...]

Yes, this is possible. If this is really a loophole that can be practically exploited is something that might be worth a closer look.
One could argue of course that troops don't loose health and morale instantly once they leave a city, so if the start and end the turn in one....

[bigus]

[Edit:] I did'nt see the post by Jagger but I'll ask again.............[End Edit]
Primasprit are you a teacher? If you are , I wish I had you back in my good old High school days. You were a big help to me in the Beta testing phase with your examples.

bigus

[Primasprit]

Nope, no teacher. I am working at a university though. But the real reason is that I am very slow in understanding things and need always long explanations.

[Jagger]

Yes, this is possible. If this is really a loophole that can be practically exploited is something that might be worth a closer look.
One could argue of course that troops don't loose health and morale instantly once they leave a city, so if the start and end the turn in one....

I probably shouldn't have used the word abused. It will become a standard tactic to ensure troops are in cities at the end of a move as much as possible to prevent attrition. It is a logical choice if historical attrition is only calculated at the beginning or end of a turn.

Although the biggest beneficiary will be the CSA. The Union often will not have the option of using cities when on the strategic offensive. So the Union will suffer greater historic attrition.

Calculating "historic attrition" daily would be the ideal solution.

[Gray_Lensman]

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