Difference between revisions of "random"
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Lou Montana (talk  contribs) m (Text replacement  "Category:Scripting Commands ArmA2" to "Category:Scripting Commands Arma 2") 
Lou Montana (talk  contribs) m (Text replacement  "<br />" to "<br>") 

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−  [[Image:bellcurve.jpgright200px]] Random real (floating point) value from 0 (inclusive) to x (not inclusive).<br  +  [[Image:bellcurve.jpgright200px]] Random real (floating point) value from 0 (inclusive) to x (not inclusive).<br> 
−  <br  +  <br> 
−  Since Arma 3 v1.55.133393 alternative syntax is added, allowing the definition of [https://en.wikipedia.org/wiki/Normal_distribution Gaussian Distribution]<ref>Technically, it is a rescaled [https://en.wikipedia.org/wiki/Bates_distribution Bates distribution] with n = 4. The distribution is split in two at its midpoint and scaled linearly such that its maximum lies at the specified midpoint.</ref> params. Uses the same method as [[setTriggerTimeout]] command. Quite useful for spawning loot for example, making more valuable items more rare ('''Alternative Syntax 1''')<br  +  Since Arma 3 v1.55.133393 alternative syntax is added, allowing the definition of [https://en.wikipedia.org/wiki/Normal_distribution Gaussian Distribution]<ref>Technically, it is a rescaled [https://en.wikipedia.org/wiki/Bates_distribution Bates distribution] with n = 4. The distribution is split in two at its midpoint and scaled linearly such that its maximum lies at the specified midpoint.</ref> params. Uses the same method as [[setTriggerTimeout]] command. Quite useful for spawning loot for example, making more valuable items more rare ('''Alternative Syntax 1''')<br><br> 
Since Arma 3 v1.67.139663 two alternative syntaxes are available:  Since Arma 3 v1.67.139663 two alternative syntaxes are available:  
* allowing to generate semirandom number based on provided seed ('''Alternative Syntax 2''')  * allowing to generate semirandom number based on provided seed ('''Alternative Syntax 2''')  
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This will yield numbers between 100 and 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.  * 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.<br  +  * The number returned is unlikely to be a whole number.<br> 
To return a whole number use either '''[[round]]''', '''[[ceil]]''' or '''[[floor]]''' together with [[random]]:  To return a whole number use either '''[[round]]''', '''[[ceil]]''' or '''[[floor]]''' together with [[random]]:  
<code>x = round(random 5) will return 0,1,2,3,4 or 5. (nonuniform distribution, 0 and 5 are half as likely to be selected than any of the other numbers)  <code>x = round(random 5) will return 0,1,2,3,4 or 5. (nonuniform distribution, 0 and 5 are half as likely to be selected than any of the other numbers) 
Revision as of 12:23, 19 March 2020
Description
 Description:
 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 semirandom number based on provided seed (Alternative Syntax 2)
 generating pseudorandom 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)
 Groups:
 Uncategorised
Syntax 1
Syntax 2
 Syntax:
 random [min, mid, max] Template:since
 Parameters:
 [min, mid, max]: Array
 min: Number
 mid: Number
 max: Number
 Return Value:
 Number
Syntax 3
 Syntax:
 seed random x Template:since
 Parameters:
 seed: Number
 x: Number
 Return Value:
 Number  value from 0 to x
Syntax 4
 Syntax:
 seed random [x, y] Template:since
 Parameters:
 seed: Number
 [x, y]: Array position on the Perlin noise texture
 x: Number
 y: Number
 Return Value:
 Number  value from 0 to 1
Examples
 Example 1:
_rNumber = random 1;
 Example 2:
_rNumber = random 10;
 Example 3:
 Generate a random position inside a circle (see also Example Code: Random Area Distribution)
_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; // Template:since _random = selectRandom _array;
Additional Information
Notes

Report bugs on the Feedback Tracker and/or discuss them on the Arma Discord or on the Forums.
Only post proven facts here! Add Note
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.
x = round(random 5) will return 0,1,2,3,4 or 5. (nonuniform 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%
 ↑ Technically, it is a rescaled Bates distribution with n = 4. The distribution is split in two at its midpoint and scaled linearly such that its maximum lies at the specified midpoint.
Categories:
 Scripting Commands
 Introduced with Operation Flashpoint version 1.00
 Operation Flashpoint: New Scripting Commands
 Operation Flashpoint: Scripting Commands
 Command Group: Uncategorised
 Scripting Commands OFP 1.46
 Scripting Commands OFP 1.96
 Scripting Commands OFP 1.99
 Scripting Commands ArmA
 Scripting Commands Arma 2
 Scripting Commands Arma 3
 Scripting Commands Take On Helicopters
 Command Group: Variables