Need Help Understanding Pregnancy Chance Calulation

[NymphoElf]

I looked at the pregnancy chance calculations on the wiki but I'm not sure I understand them. Can someone who does understand them please give me a breakdown? I did my best to re-create the code, and from what I put together it seems like it might be correct, but I simply don't know.

Thanks in advance

 

[TheShepard256]

It pretty much looks like this graph:

with the values at the bottom being the average of the mother's fertility and the sire's virility. So, if your Champ and the other parent both have 100% of the respective stat, they'd average to 100% = 1, and from this graph you can see that'd give a pregnancy chance of a bit over 0.2 = 20%.

 

[Burnerbro]

Thanks. My brain was reaching a boiling point from trying to remember enough high-school algebra to solve that shizz.

 

[NymphoElf]

It pretty much looks like this graph:
View attachment 18834
with the values at the bottom being the average of the mother's fertility and the sire's virility. So, if your Champ and the other parent both have 100% of the respective stat, they'd average to 100% = 1, and from this graph you can see that'd give a pregnancy chance of a bit over 0.2 = 20%.

Wait, wouldn't that be nearly 100%? If the bottom value is the average of Virility and Fertility, what does the Y axis represent? I would have thought that was % chance, where 1 = 100%?

Using a graphing calculator, I come up with the same line for C=(1-(e^-0.25x)) and I'm assuming x = the Average of Virility & Fertility. When x = 1, That's giving me a % chance of ~22%. Unless when you said "100% of the value" you simply meant both Fertility and Virility equaled 1, and not the maximum it could be (which I believe is 10?).

 

[Alypia]

the maximum it could be (which I believe is 10?).

The maximum for fertility and virility with just pink/blue egg TFs is indeed 10, but the maximum for them with other stuff (like Evergreen's services) is much higher. I think it's even uncapped.

But since the curve looks like that, high virility and fertility numbers have very rapidly diminishing returns. 10 of the relevant stat is all you're likely to need for a maxed-out breeding Champ.

 

[TheShepard256]

Wait, wouldn't that be nearly 100%? If the bottom value is the average of Virility and Fertility, what does the Y axis represent? I would have thought that was % chance, where 1 = 100%?

Using a graphing calculator, I come up with the same line for C=(1-(e^-0.25x)) and I'm assuming x = the Average of Virility & Fertility. When x = 1, That's giving me a % chance of ~22%. Unless when you said "100% of the value" you simply meant both Fertility and Virility equaled 1, and not the maximum it could be (which I believe is 10?).

Yes, the Y-axis is pregnancy chance, with 1 (the line at the top of the included graph) being 100% pregnancy chance. And when I said "100% of the respective stat", I did indeed mean x = 1; I'm more used to TiTS which lists fertility and virility as percentages, which is why I said "100%" and not "1" (they're the same thing, anyways).

 

[Prent]

The maximum for fertility and virility with just pink/blue egg TFs is indeed 10, but the maximum for them with other stuff (like Evergreen's services) is much higher. I think it's even uncapped.

But since the curve looks like that, high virility and fertility numbers have very rapidly diminishing returns. 10 of the relevant stat is all you're likely to need for a maxed-out breeding Champ.

Dunno about Fertility, but I once tried to find out if Evergreen had a virility cap. I got bored at around 1,500.

 

[NymphoElf]

@Alypia @TheShepard256 Ok. Thank you both very much!

I feel like the COC2 Wiki does not explain this very well. The calculation spoiler is currently written as:

Average of (virility + fertility)/2
Healthy Curve = (1 - Math.exp(-0.25*value))
HealthyCurve(Average)*10000 > rand(10000)

I feel like it should be written as:

1) First we find the Average (A) of both partners' breeding stats:
A = (Virility + Fertility)/2

2) Then, this value is used in the following formula, where C is the overall chance of conception:
C = (1 - (e^-0.25*A))
Note: C will be a number between 0 and 1, with 1 representing a 100% chance of success, but it is impossible to truly reach 100% based on the formula. "e" is known as "Euler's Number" and roughly equals 2.71828.

3) Finally, a check is made to determine if the PC/NPC has become pregnant, represented by the following function:
C*10000 > rand(10000)

"rand(10000)" is a randomly generated number between 0 and 10000.

If "C*10000" is greater than the randomly generated number (meaning the function is "True"), the PC/NPC becomes pregnant.

The way it's currently written required some prior knowledge in programming as well as a lot of critical thinking to sus out (plus I'm not sure if it's technically "correct" in the way it's written), and even then I had to resort to coming to the forums to get my question truly answered. Granted, you'll still need to know what "^" means when written like this, and at least know what exponents are in mathematics, but I believe this will be more "user friendly" in figuring out their pregnancy chance.

Does anyone know who to contact regarding a suggested edit to the wiki?

 

[Burnerbro]

Does anyone know who to contact regarding a suggested edit to the wiki?

You can try this thread dedicated to wiki and its editing. Atm it seems like you can't create a new wiki account in case you want to edit the page yourself.

@Savin sorry to bother you, but I'd like to ask if the dev team are the ones controlling the access to the various FenCo wikis, or if it is entirely fan supported?