Price decay of 14% per six hours doesn't work out? Nor does 0.14% per six hours.

End value = starting value * (1 - b)^x, where b is the percent decrease and X is the period of time. We want to solve for b. This is the formula for exponential decay.

3,698,000 = 8,000,000(1 - b)^90
0.46255 = (1 - b)^90, now we take the 90th root of both sides.
0.991462768 = 1 - b, now rearrange the equation to isolate b.
b = 1 - 0.991462768

b = 0.008537232, which = 0.8537232% per day. Divide this by 24 then multiply by six for the decrease every 6 hours.

b = 0.2134308% every six hours.

So according to their numbers, it's actually decreasing by ~0.21% every six hours, not the 0.14% they probably meant to say. Maybe someone can check my math, I posted this from my phone.

For completeness' sake, if we use the 14% they provided and plug it into the formula, we need to tweak the time a little bit. 90 days x 24 hours = 2,160 hours, divide by 6 to get 360 decays. This will be our x.

M = 8,000,000(1 - 0.14)^360

M = 2.10 * 10^-17, which is obviously WAY off. If we assume they meant 0.14% every six hours, we'll end up with...

M = 8,000,000(1 - 0.0014)^360
M = 4,831,168.733, which is a lot closer to their stated value, but still wrong.

Can we get some clarification on what the actual rate of decay is?

Edit: Apparently it decays linearly based on the original price and not exponentially. That's pretty poorly worded in the patch notes, methinks.

The patch notes, had a lot of errors and typos. Clarification would be nice..

Need to take the 360th root, but the way you did it was reasonably close.

0.46255 = (1 - b) ^360

b = ~0.002141175 (every 6 hrs)

So yeah, by my math, decreasing at 0.214% every 6 hours (roughly)

The actual rate IS 0.14% They never claimed it was exponential decay, it decays based on the initial cost. That means in the case of a 8,000,000 gil plot, the price goes down by 11,200 gil every 6 hours.

Well, I went for a per day decrease and then converted to six hours because their timeline was in units of days, not hours, but both ways are the same answer rounded to two decimal places anyway.

Quote:

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Originally Posted by Beardfist

The actual rate IS 0.14% They never claimed it was exponential decay, it decays based on the initial cost. That means in the case of a 8,000,000 gil plot, the price goes down by 11,200 gil every 6 hours.

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0.14% = 0.0014

1 - (0.0014 * 360) = 0.496

Which isn't quite the 0.46225, but yeah, it's closer and it's not an exponential decay.

If the decay is linear, 0.1494% is closer to the mark.

Lol, what SE meant to say was "Pricing will decrease every 6 hours by 14% of whateverthehellwefeellikesaying. Tyvm."

It works if you zoom out.

I used base*(1-(n*0.0014)) where n is the number of 4hr reductions that have gone by and base is the base cost or the plot as my equation, it's basically the same as Beardfist's, and fits in with what SE did for the patch notes