random

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Revision as of 13:05, 8 March 2019 by bovine3dom (talk | contribs) (Added link to correct distribution for people who would be very confused at the concept of a minimum and maximum for a normal distribution.)
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Introduced with Operation Flashpoint version 1.00
  

Click on the images for descriptions

Introduced in

Game:
Operation Flashpoint
Version:
1.00

Description

Description:
bellcurve.jpg
Random real (floating point) value from 0 (inclusive) to x (not inclusive).


Since Arma 3 v1.55.133393 alternative syntax is added, allowing the definition of Gaussian Distribution[1] params. Uses the same method as setTriggerTimeout command. Quite useful for spawning loot for example, making more valuable items more rare (Alternative Syntax 1)

Since Arma 3 v1.67.139663 two alternative syntaxes are available:

  • allowing to generate semi-random number based on provided seed (Alternative Syntax 2)
  • generating pseudo-random noise texture based on provided seed and returning a single number between 0 (included) and 1 (excluded) at supplied x and y coordinates (Alternative Syntax 3)

Syntax

Syntax:
random x
Parameters:
x: Number
Return Value:
Number

Alternative Syntax

Syntax:
random [min, mid, max]        (Since Arma 3 v1.55.133393)
Parameters:
[min, mid, max]: Array
min: Number
mid: Number
max: Number
Return Value:
Number

Alternative Syntax 2

Syntax:
seed random x        (Since Arma 3 v1.67.139663)
Parameters:
seed: Number
x: Number
Return Value:
Number

Alternative Syntax 3

Syntax:
seed random [x, y]        (Since Arma 3 v1.67.139663)
Parameters:
seed: Number
[x, y]: Array position on the Perlin noise texture
x: Number
y: Number
Return Value:
Number

Examples

Example 1:
_rNumber = random 1;
Example 2:
_rNumber = random -10;
Example 3:
Generate random position inside a circle _center getPos [_radius * sqrt random 1, random 360];
Example 4:
To select random value from an array: _array = ["apples", "pears", "bananas", "M16"]; _random = _array select floor random count _array; // since Arma 3 v1.55.133393 _random = selectRandom _array;

Additional Information

Multiplayer:
-
See also:
Math CommandsselectRandomselectRandomWeighted

Notes

Only post proven facts here. Report bugs on the feedback tracker. Use the talk page or the forums for discussions.
Add New Note | How To

Notes

Posted on July 12, 2015 - 20:32 (UTC)
Hcpookie
Random selections including negative numbers can be obtained via: _Xrnd = round(random 200) -100; This will yield numbers between -100 and 100.
  • Be careful using random numbers in multiplayer, each client will come up with a different result. See multiplayer tutorials for more general information about locality.
  • The number returned is unlikely to be a whole number.
To return a whole number use either round, ceil or floor together with random: x = round(random 5) will return 0,1,2,3,4 or 5. (non-uniform distribution, 0 and 5 are half as likely to be selected than any of the other numbers) x = floor(random 5) will return 0,1,2,3 or 4. (uniform distribution, all numbers have the same probability of being selected) x = ceil(random 5) will return 0,1,2,3,4 or 5. (0 is very unlikely, but possible, as ceil 0 is 0)
Posted on July 22, 2018 - 12:58 (UTC+2)
Lou Montana
Repartition comparison
Formula 0 1 2 3 4 5 6 7 8 9
floor random 10; 10% 10% 10% 10% 10% 10% 10% 10% 10% 10%
floor random [0, 5, 10] 0% 2% 7% 17% 25% 25% 17% 7% 2% 0%
floor random [0, 10, 0] 0% 0% 1% 2% 5% 9% 14% 19% 24% 26%
floor random [0, 10, 5] 0% 0% 0% 1% 2% 5% 9% 16% 28% 38%
  1. Technically, it is a rescaled Irwin-Hall Distribution with n = 4.