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  1. #1
    Player
    Obsidian's Avatar
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    Aug 2011
    Posts
    19
    Character
    Lowen Lochlan
    World
    Balmung
    Main Class
    Gladiator Lv 50

    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.
    (2)
    Last edited by Obsidian; 12-15-2013 at 05:57 AM.

  2. #2
    Player
    Escadora's Avatar
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    Sep 2013
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    159
    Character
    Ari Gatou
    World
    Gilgamesh
    Main Class
    Archer Lv 80
    The patch notes, had a lot of errors and typos. Clarification would be nice..
    (0)

  3. #3
    Player
    Castillan's Avatar
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    Oct 2013
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    129
    Character
    Castillan Lionheart
    World
    Zalera
    Main Class
    Conjurer Lv 50
    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)
    (0)

  4. #4
    Player
    Beardfist's Avatar
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    Oct 2013
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    17
    Character
    Wyra Lyehga
    World
    Goblin
    Main Class
    Archer Lv 50
    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.
    (0)

  5. #5
    Player
    Obsidian's Avatar
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    Aug 2011
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    19
    Character
    Lowen Lochlan
    World
    Balmung
    Main Class
    Gladiator Lv 50
    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.
    (0)

  6. #6
    Player
    Castillan's Avatar
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    Oct 2013
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    Character
    Castillan Lionheart
    World
    Zalera
    Main Class
    Conjurer Lv 50
    Quote Originally Posted by Beardfist View Post
    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.
    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.
    (0)

  7. #7
    Player
    GilbertLapine's Avatar
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    Aug 2013
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    403
    Character
    Malcolm Quill
    World
    Ultros
    Main Class
    Thaumaturge Lv 50
    Lol, what SE meant to say was "Pricing will decrease every 6 hours by 14% of whateverthehellwefeellikesaying. Tyvm."
    (0)

  8. #8
    Player
    Kayokane's Avatar
    Join Date
    Mar 2011
    Location
    Limsa Lominsa
    Posts
    429
    Character
    Aluena Mahri
    World
    Hyperion
    Main Class
    White Mage Lv 100
    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
    (0)
    Last edited by Kayokane; 12-15-2013 at 05:50 AM. Reason: forgot 00 for .14% conversion

  9. #9
    Player
    AlmaMalma's Avatar
    Join Date
    Mar 2011
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    143
    Character
    Alma Malma
    World
    Ragnarok
    Main Class
    Blacksmith Lv 50
    It works if you zoom out.
    (1)