4 ms·

When I was little (and had too much free time) I memorized many digits of some transcendental numbers. The only (semi)practical use I've found for that knowledg

by zzrg 10y ago

When I was little (and had too much free time) I memorized many digits of some transcendental numbers. The only (semi)practical use I've found for that knowledge, is that I can use it as a reasonably good pseudorandom stream. If for some reason I have to choose things pseudorandomly. Pick an arbitrary starting point in pi, and press 'd' for even digits and 'f' for odd digits, I get around 0.49 accuracy with this oracle.

grondilu 10y ago
Well, that only shows that this oracle can be improved. It should be able to recognize that pattern from a well known transcendental number.
- jobigoud 10y ago
  That might be a slippery slope though. Is a known random sequence less random than an original one? Should a randomness detector keep a database of all random sequence ever produced to give lower scores to known ones?
snikeris 10y ago
Haha, I did the same thing! From memory: 3.141592653589793238462643383279502884197969399375105 Now, the interesting question, how accurate is my recollection after all these years? Ack, one digit off!
- maxander 10y ago
  If a transcendental number is imperfectly remembered, are its digits thereby less random?
  - snikeris 10y ago
    More random, I'd say.
- schoen 10y ago
  141592653589793238462643383279502884197969399375105... that 9 should be a 1, right?
  - snikeris 10y ago
    Indeed.
3pt14159 10y ago
I imagined how I would have coded it and so I devised a system to get it down as low as possible. I ended up with 0.44 accuracy. Pure random would have been better :)
perennate 10y ago
Mm I did something similar, doesn't need memorization though: arbitrarily form sentences, go through the letters in order, and pick 'd' for a-m and 'f' for n-z. Of course there will be some patterns, but it's sufficient for this. And I think this strategy uses more free will :P
thaumasiotes 10y ago
You don't need a transcendental number; simple counting has perfect entropy: 0 1 10 11 100 101 110 111 1000 1001 1010 1011 1100 1101 1110 1111 10000... (Granted, that is a transcendental number -- the Champernowne constant for base 2 -- but there's no real need to think of it that way.)
- steego 10y ago
  I wrote a program that counts but only appends the sequence if the binary sequence isn't already there.
  - thaumasiotes 10y ago
    > but only appends the sequence if the binary sequence isn't already there Why?
- Bognar 10y ago
  This sequence seems to settle right around 50%: var simulateKeyPress = function(character) { var evt = document.createEvent("KeyboardEvent"); evt.initKeyEvent ("keypress", true, true, window, 0, 0, 0, 0, 0, character.charCodeAt(0)) document.body.dispatchEvent(evt); }; var num = 0; var loop = function() { console.log(num); var binary = num.toString(2); num++; for(var i = 0, len = binary.length; i < len; i++) { simulateKeyPress(binary[i] == '0' ? 'd' : 'f'); } }; setInterval(loop, 100);
  - thaumasiotes 10y ago
    It might sound weird, but I actually found that more readable as three lines of code. :/
talaketu 10y ago
but what if the challenge was not 2 chars but 3 (d, e, f)? pi (base 9) = 3.12418812407442788645177761731035828516545353462652301126321450283864034354163303086781327...

by zzrg 10y ago

grondilu 10y ago

Well, that only shows that this oracle can be improved. It should be able to recognize that pattern from a well known transcendental number.

jobigoud 10y ago
That might be a slippery slope though. Is a known random sequence less random than an original one? Should a randomness detector keep a database of all random sequence ever produced to give lower scores to known ones?

snikeris 10y ago

Haha, I did the same thing! From memory: 3.141592653589793238462643383279502884197969399375105 Now, the interesting question, how accurate is my recollection after all these years? Ack, one digit off!

maxander 10y ago
If a transcendental number is imperfectly remembered, are its digits thereby less random?
- snikeris 10y ago
  More random, I'd say.
schoen 10y ago
141592653589793238462643383279502884197969399375105... that 9 should be a 1, right?
- snikeris 10y ago
  Indeed.

3pt14159 10y ago

I imagined how I would have coded it and so I devised a system to get it down as low as possible. I ended up with 0.44 accuracy. Pure random would have been better :)

perennate 10y ago

Mm I did something similar, doesn't need memorization though: arbitrarily form sentences, go through the letters in order, and pick 'd' for a-m and 'f' for n-z. Of course there will be some patterns, but it's sufficient for this. And I think this strategy uses more free will :P

thaumasiotes 10y ago

You don't need a transcendental number; simple counting has perfect entropy: 0 1 10 11 100 101 110 111 1000 1001 1010 1011 1100 1101 1110 1111 10000... (Granted, that is a transcendental number -- the Champernowne constant for base 2 -- but there's no real need to think of it that way.)

steego 10y ago
I wrote a program that counts but only appends the sequence if the binary sequence isn't already there.
- thaumasiotes 10y ago
  > but only appends the sequence if the binary sequence isn't already there Why?
Bognar 10y ago
This sequence seems to settle right around 50%: var simulateKeyPress = function(character) { var evt = document.createEvent("KeyboardEvent"); evt.initKeyEvent ("keypress", true, true, window, 0, 0, 0, 0, 0, character.charCodeAt(0)) document.body.dispatchEvent(evt); }; var num = 0; var loop = function() { console.log(num); var binary = num.toString(2); num++; for(var i = 0, len = binary.length; i < len; i++) { simulateKeyPress(binary[i] == '0' ? 'd' : 'f'); } }; setInterval(loop, 100);
- thaumasiotes 10y ago
  It might sound weird, but I actually found that more readable as three lines of code. :/

talaketu 10y ago

but what if the challenge was not 2 chars but 3 (d, e, f)? pi (base 9) = 3.12418812407442788645177761731035828516545353462652301126321450283864034354163303086781327...