Archive for July, 2015
Fisher-Yates shuffle for music streaming is perfectly random—too much so for some
Posted by mark in Basic stats & math, Consumer behavior on July 28, 2015
The headline “When random is too random” caught my eye when the April issue of Significance, published by The Royal Statistical Society, circulated by me the other day. It really makes no statistical sense, but the music-streaming service Spotify abandoned the truly random Fisher-Yates shuffle. The problem with randomization is that it naturally produces repeats in tracks two or even three days in a row and occasionally back-to-back. Although this happened purely by chance, Spotify consumers complained.
Along similar lines, I have been aggravated by screen savers that randomly show family photos. It really seems that some get repeated too often even though it’s only by chance. For a detailing of how Spotify’s software engineer Lukáš Poláček tweaked the Fisher-Yates shuffle to stretch songs out more evenly see this blog post.
“I think Fisher-Yates shuffle is one of the most beautiful random algorithms and it’s amazing that such a complicated problem can be solved in 3 lines of code in some programming languages. And this is accomplished using the optimal number of operations and optimal amount of randomness.”
– Lukáš Poláček (who nevertheless, due to fickleness of music listeners, tweaked the algorithm to introduce a degree of unrandomization so it would reduce natural clustering)
New Summer Glory Index provides proof positive of great weather
Minnesotans love to point out what a pain in the posterior (PIP) it is to endure the climate from November through March. Minnesota’s Department of Natural Resources (DNR) State Climatology Office (SCO) quantifies the suffering with this Winter Misery Index (WMI). As you can see by their chart, last year’s WMI ranked highly for PIP.
I actually like the cold (good for ice skating!) and snow (great for cross-country skiing). Therefore I agree with the DNR suggesting the WMI be renamed WFI, that is, Winter Fun Index. However, even I must admit to favoring spring, summer and fall over the winter.
It’s been especially nice here for the past few months—only a few really hot days. This is confirmed by the MN DNR climatology wonks who concocted this Summer Glory Index (SGI). They figure the sweet spot (“full credit”) is high and low temperatures of 73-79 F and 57-64, respectively, with less than 60 F dew point and at most 0.01 inches of rain. By these measures we Twin Citians are enjoying a mostly glorious summer.
Looking back some years on the chart a few summers fall into the “wretched” category, primarily due to extreme heat. I recall many a summer night lying awake in my upper bunk on the second floor of our home in St. Paul with the window pulled down and begging for the least bit of breeze. That really was wretched. Thank goodness for air conditioning now being so ubiquitous in buildings and vehicles!
Check out my granddaughter Laine enjoying our great outdoors. Glory be! : )
For count of calories it is nary the area of the Oreo but the thickness
In a new twist on sandwich cookies, the manufacturer of Oreo brand cookies, Chicago-area based Mondelez International, now offers a thin version with a 12.5% reduction in calories per serving. (From what I gather off the internet a “serving” seems to vary from 2 to 4 cookies, depending on the thickness, I suppose. For example, I would not advise eating four Mega Stuf Oreos in one sitting.)
The Detroit Free Press gives the 7.5 mm thick Oreo Thins two thumbs up in this July 6 review. Unfortunately the reduction in filling from the 12.5 mm thick regular cookie closes out as a practical matter the option for splitting them apart, which normally about half of Oreo cookie-eaters do, according to Mondelez.
These thin confections are likened by the Oreo maker to crepes, perhaps to be eaten only at fancy teas in the mid-afternoon by proper ladies and gentlemen. To me that is a deal breaker. I plan to eschew the Thins in favor of the Mega Stuf, which according to this “implusive” blogger who will eat “anything edible no matter how strange” contains 52.5% more filling than Double Stuf.
Come to think of it, the food scientists at Mondelez really out to come up with an Oreo that is comprised only of the crème filling—saving us the trouble of having to twist them apart.