About
Think of randomness as a lack of pattern.
Something random should be unpredictable. We shouldn’t be able to predict the next value of the sequence
The degree to which a system has no pattern is known as entropy.
See also:
The opposite of random is deterministic.
Example of bad random sequence
| Type Sequence | Example |
|---|---|
| Uniform sequence | 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 |
| Repeated sequence | 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 |
| Too many low numbers | 1 3 2 5 3 9 1 2 4 2 5 1 1 2 8 1 5 2 3 4 |
| Too many even numbers | 2 8 4 6 0 9 8 2 4 8 6 4 2 2 5 1 4 8 6 2 |
Type
True
A high-entropy source is completely chaotic, is unpredictable, and is called true randomness.
Where computers fail at creating true randomness (see pseudo), the physical world does not. Truly random seed numbers can be derived from the unpredictability of physical processes itself (radioactive decay, imprecision of taking measurements)
A truly random distribution is:
- and the distribution of the error from the mean is normal. Is it why the Central Limit Theorem works ?
Demo with pseudo number:
- A helper function to draw an histogram
- Creating the population data randomly distributed
- Building and getting the bins
- Getting the bin
- The HTML page
Pseudo
As digital computers are deterministic, truly randomness within a computer doesn't exist.
It turns out to be mathematically impossible to generate true random numbers using a digital computer, but it is possible to generate pseudo-random numbers. See Number - Pseudo-random Numbers
Pseudo-random distribution.
Random Subject
Test
Graph
Documentation / Reference
- https://qz.com/1642628/cloudflare-uses-lava-lamps-to-generate-a-crucial-resource/ - lava-lamps as true randomness source