What does randomness look like?

Post by henrikschroder » Sat, Dec 22, 2012, 10:08 AM UTC

baddox wrote: post #48

henrikschroder wrote: post #23

Earlier quoted context omitted.

Oh yes. Our intuition is that random is fair and uniform, but it's absolutely not. I was bit by another random quirk in World of Warcraft. There was a long-running achievement called "What a Strange Long Journey it has Been", which took at least a year in real-time to complete, and you had to actively play during each of the ten or so in-game festivals and holidays, and do some quests and tasks during each. If you mi…

> Oh yes. Our intuition is that random is fair and uniform, but it's absolutely not. But a uniform distribution is random, isn't it? This sort of phrasing is rampant in this thread, and I'm confused by it. How can a uniform distribution be considered non-random, or "less" random than another distribution?

Post by InclinedPlane » Sat, Dec 22, 2012, 11:29 AM UTC

baddox wrote: post #48

henrikschroder wrote: post #23

Earlier quoted context omitted.

Oh yes. Our intuition is that random is fair and uniform, but it's absolutely not. I was bit by another random quirk in World of Warcraft. There was a long-running achievement called "What a Strange Long Journey it has Been", which took at least a year in real-time to complete, and you had to actively play during each of the ten or so in-game festivals and holidays, and do some quests and tasks during each. If you mi…

> Oh yes. Our intuition is that random is fair and uniform, but it's absolutely not. But a uniform distribution is random, isn't it? This sort of phrasing is rampant in this thread, and I'm confused by it. How can a uniform distribution be considered non-random, or "less" random than another distribution?

Post by heyitsnick » Sat, Dec 22, 2012, 12:24 PM UTC

michaelochurch wrote: post #53

chimeracoder wrote: post #45

Earlier quoted context omitted.

> This reminds me of Magic: the Gathering and the misery of mana screw. Incidentally, apparently people complain about the online versions of the game providing a land distribution that's "too even". Also, while mana screw sucks, between the fact that you can decide whether or not to begin with a certain opening hand and the fact that you can design your deck around such circumstances (mana fixing, proper distributio…

Incidentally, apparently people complain about the online versions of the game providing a land distribution that's "too even". Online bridge has a similar problem. Four riffle shuffles (which does not fully randomize hands) is typical in bridge games, and this means that long suits (and, thus, better hands) are more common. Early online bridge games randomized hands fully and therefore delivered crappier (flatter) h…

Post by YokoZar » Sat, Dec 22, 2012, 1:54 PM UTC

joe_the_user wrote: post #15

henrikschroder wrote: post #11

Back in the day I was in a raiding guild in World of Warcraft. And back then, each boss monster in a raid dungeon had a loot table, and when you killed it, your raid got a few pieces of random loot. And I don't know how many times I, and the other guy in the guild who understood statistics, had to explain to the others that random doesn't mean uniform. If a certain piece of armour has a 1/X chance to drop from a boss…

Yeah, And you know, it is always possible in those situations that there is a broken pseudo-random number generator involved. But of course, that's really hard to tell too because real randomness is so unrandom seeming.

Post by dgallagher » Sat, Dec 22, 2012, 2:28 PM UTC

    from PIL import Image, ImageDraw
    from random import randint
    
    def random_image():
        
        width       = 666
        height      = 666
        file_name   = '/Users/Dave/%dx%d' % (width, height)
        path_png    = file_name + '.png'
        path_jpg    = file_name + '.jpg'
        path_bmp    = file_name + '.bmp'
        path_tif    = file_name + '.tif'
        
        img  = Image.new("RGB", (width, height), "#FFFFFF")
        draw = ImageDraw.Draw(img)
        
        for height_pixel in range(height):
            if height_pixel % 100 is 0:
                print height_pixel
            
            for width_pixel in range(width):
                r  = randint(0, 255)
                g  = randint(0, 255)
                b  = randint(0, 255)
                
                dr = (randint(0, 255) - r) / 300.0
                dg = (randint(0, 255) - g) / 300.0
                db = (randint(0, 255) - b) / 300.0
                
                r  = r + dr
                g  = g + dg
                b  = b + db
                
                draw.line((width_pixel, height_pixel, width_pixel, height_pixel), fill=(int(r), int(g), int(b)))
            
        img.save(fp=path_png, format="PNG")
        img.save(fp=path_jpg, format="JPEG", quality=95, subsampling=0)     # 100 quality is 2x to 3x file size, but you won't see a difference visually.
        img.save(fp=path_bmp, format="BMP")
        img.save(fp=path_tif, format="TIFF")
    
    
    if __name__ == "__main__":
        random_image()