{"id":156,"date":"2014-04-22T06:27:00","date_gmt":"2014-04-22T06:27:00","guid":{"rendered":"http:\/\/128.199.128.224\/random-thoughts\/"},"modified":"2017-10-05T07:46:04","modified_gmt":"2017-10-04T22:46:04","slug":"random-thoughts","status":"publish","type":"post","link":"https:\/\/naganashi.com\/kanjiflow\/random-thoughts\/","title":{"rendered":"Random Thoughts"},"content":{"rendered":"

This is going to be another boring post. It\u2019s specifically regarding how the app shuffles cards and randomness in general but its also going to get into things like statistics and heuristics.<\/p>\n

The short story is that new cards show up in order during their first study session. This is because I like to edit my cards from the Study View and I\u2019m usually working from a list. If you don\u2019t want new cards to show up in order there is a setting you can enable to randomize them. For cards that are not new, I use arc4random_uniform([array count])<\/code> to choose random numbers and a Fisher-Yates shuffle<\/a> to actually shuffle the cards. Even though these procedures may seem to be the best and\/or most standard ways of getting random numbers and shuffling a set, you might still notice patterns and\/or the resulting shuffles might not seem random to you. How can that be?<\/p>\n

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Computers are not really capable of choosing things at random. Generally speaking, when one asks a computer to generate a random number it must go through some process to create that number. It might use the current time or some other internally-known condition (voltage, temperature, etc.) as a basis for generating the number. If we could recreate the precise condition or conditions that existed in a system when it generated a random number, we could cause that system to generate the same random number over and over again. That\u2019s not truly random. The same thing is true of the universe. If you precisely reproduce the conditions of the universe (and I mean the precise position, velocity, and spin of every fundamental particle in existence), you will always get the same outcome (quantum fluctuations not withstanding). Even though you may think you have free will, you wouldn\u2019t be able to change your mind if everything were precisely<\/em> the same. Given the same conditions, you must always choose Pepsi instead of Coke. Given the same<\/em> conditions.<\/p>\n

I personally prefer Coke, by the way. But there must be some conditions that would cause me to choose Pepsi. I can\u2019t really imagine what those conditions might be but if they existed, I must choose Pepsi. And if we recreated those conditions precisely through many trials, I would choose Pepsi every time. Get it? I would not be able to change my mind.<\/p>\n

But, can that really be true? Certainly, you can change your mind and random things do happen all the time, right? Well, now we\u2019re getting into a philosophical debate. What does random mean? Does it mean something that seems random to people and not something that is actually random in the mathematical sense? If we\u2019re only concerned about things that seem random to people then, yes, randomness does exists. If we\u2019re talking about mathematical randomness\u2026actually, I\u2019m not sure.<\/p>\n

I think truly random things may not exist (again, ignoring the quantum world) but what we can do is try to reach a state of being as random as possible and call that state mathematical randomness. It\u2019s just like circles. While we can mathematically describe a circle, in fact there seem to be none. There seems to be nothing in existence that is actually round. There are very round things. Things that are so round that they are almost truly round. Things like the sun – the roundest thing we know of. But we are capable of measuring the fact that it is not round. What we mean when we call something round is that it is round enough to be practically round. What I mean when I say random is just random enough to be practically random.<\/p>\n

So, let us ignore the possibility that randomness may not even truly be possible. Let\u2019s just establish a model with two phrases: seems to be random<\/em> and mathematically random<\/em>. Seems to be random will simply mean that it\u2019s difficult for the average person to notice a pattern and mathematically random will mean that it\u2019s actually approaching a smooth distribution curve.<\/p>\n

When I implement a random function, such as a function that should shuffle or choose virtual flashcards at random, do I want mathematical randomness or do I want something that seems random to people? Well, wait a second. Shouldn\u2019t that be the same thing? If it\u2019s as random, or pseudo-random as it were, as it\u2019s possible for a computer to be, won\u2019t that also seem random to people?<\/p>\n