Rebirths math problem

Help and Feedback Scripting Support
#17

Why are you guys making it this complicated, just use a exponential scale. Any equation of the form y=n^x will work fine, where n is the steepness of the function and x would be the amount of rebirths which you can track by your own means. Using a for loop for any sort of math that isn’t integration(but even integration in most cases) is a massive sign you’re doing something terribly wrong.

#18

he wants the total price of multiple iterations of buying a rebirth not just the price of a specific rebirth

#19

Yes, exactly, I want to be able to calculate the next price and add it to the current one.

#20

Then just integrate whatever formula (exponential formula in this case) for calculating the price and do the exact same thing.

#21

My question is what is the formula?

#22

This is exactly what arithmetic series sums do as I have said above. To get the price of x amount of rebirths it would be s(currentRebirths + x) - s(currentRebirths) where s is the sum function. Refer to my post above for code.

#23

I edited post above, but here it is again:

scale = 10000
final_cost = 0.5*scale * HowManyRebirths * (HowManyRebirths + 2*RebirthsIHave - 1)
#24

Wow, thank you! This is what I was looking for! I printed it and it printed out the exact number I wanted.

1 Like
#25

that will give you your first rebirth free
just so you know

1 Like
#26

Yea, I’ll try to find something for this by myself. Thanks for this notice!

#27

check my first response, it is a very similar formula but it shifts everything 1 spot so starting at 0, it is 10k

#28 
local e = 10 -- steepness of the scale

function expoScale(x)
  return e^x
end

function expoScaleInt(x)
  return (e^(x+1)-1)/(e-1)
end

is what you want

#29

But I don’t understand it, could you repost it more clearly now?

#30

Yours work perfectly but doesn’t include how many rebirths you have rn.

#31

expoScale gives you a curve exponentially increasing by e, expoScaleInt is the analytic form for the series sum of that function.

#32

It is just variables, put your variable for current rebirths in for cR and how many they buy for nR

1 Like
#33

The fundamental theorem of calculus says you can just subtract whatever the sum of a series from the sum of a series to get the sum over an interval, thus

expoScaleInt(goalRebirths) - expoScaleInt(currentRebirths)

is what you would want to do.

#34

What is the 2cR? its erroring me this

Rebirth system help
#35

its just 2*cR, sorry for the confusion. formatting removes * and such

#36

When RebirthsIHave=0 and HowManyRebirths=1 then the price is 0. If that’s not what you want, then you’ll need to shift things so that costs something else (probably 10000).

The fn that Pharyx_Styx posted is pretty much identical to the one I ended up with. Just change the -1 at the end of the fn to +1 and it will shift everything up by 10k.

I was trying to replicate what you did whereas he was showing the right way to do it :smiley:
Should mark his first post as solution. He was on to the answer right from the start.

2 Likes