Difference between revisions of "random"
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m (formatting) 
Lou Montana (talk  contribs) (Add seed integer detail) 

(6 intermediate revisions by the same user not shown)  
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game1= ofp  game1= ofp  
−  
version1= 1.00  version1= 1.00  
game2= ofpe  game2= ofpe  
−  
version2= 1.00  version2= 1.00  
game3= arma1  game3= arma1  
−  
version3= 1.00  version3= 1.00  
game4= arma2  game4= arma2  
−  
version4= 1.00  version4= 1.00  
game5= arma2oa  game5= arma2oa  
−  +  version5= 1.50  
−  version5= 1.  
game6= tkoh  game6= tkoh  
−  
version6= 1.00  version6= 1.00  
game7= arma3  game7= arma3  
−  
version7= 0.50  version7= 0.50  
gr1= Math  gr1= Math  
−  descr= [[Image:bellcurve.jpgright200px]] Random real (floating point) value from 0 (inclusive) to x (not inclusive).<br>  +  descr= [[Image:bellcurve.jpgright200px]] Random real (floating point) value from 0 (inclusive) to x (not inclusive).<br><br> 
−  <br>  +  {{GVIarma31.56}} alternative syntax is added, allowing the definition of {{WikipediaNormal_distributionGaussian Distribution}}<ref>Technically, it is a rescaled {{WikipediaBates_distributionBates 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 ({{HashLink#Alternative Syntax 1}})<br><br> 
−  +  {{GVIarma31.68}} two alternative syntaxes are available:  
−  +  * allowing to generate {{WikipediaRandom seedseedbased}} random number based on provided seed ({{HashLink#Alternative Syntax 2}})  
−  * allowing to generate  +  * generating {{WikipediaRandom seedseedbased}} random noise texture based on provided seed and returning a single number between 0 (included) and 1 (excluded) at supplied ''x'' and ''y'' coordinates ({{HashLink#Alternative Syntax 3}}) 
−  * generating  
s1= [[random]] x  s1= [[random]] x  
Line 58:  Line 50:  
s3= seed [[random]] x {{Sincearma31.68y}}  s3= seed [[random]] x {{Sincearma31.68y}}  
−  p41= seed: [[Number]]  +  p41= seed: [[Number]]  an '''integer'''. Any float value will be truncated (e.g 0.9, 0.1, 0.1 or 0.9 will be read as '''0''') 
p42= x: [[Number]]  p42= x: [[Number]]  
Line 68:  Line 60:  
p61= seed: [[Number]]  p61= seed: [[Number]]  
−  p62= [x, y]: [[Array]]   +  p62= [x, y]: [[Array]]  texture position (''not'' a Perlin noise) 
p63= x: [[Number]]  p63= x: [[Number]]  
Line 75:  Line 67:  
r4= [[Number]]  Value from 0 to 1  r4= [[Number]]  Value from 0 to 1  
−  +  
x1= <code>_rNumber = [[random]] 1;</code>  x1= <code>_rNumber = [[random]] 1;</code>  
Line 81:  Line 73:  
x3= Generate a random position inside a circle (see also [[Example Code: Random Area Distribution]])  x3= Generate a random position inside a circle (see also [[Example Code: Random Area Distribution]])  
−  <code>_center [[getPos]] [  +  <code>_center [[getPos]] [_radius * [[sqrt]] [[random]] 1, [[random]] 360];</code> 
x4= To select random value from an array:  x4= To select random value from an array:  
Line 92:  Line 84:  
}}  }}  
+  <dl class="command_description">  
−  
<dt></dt>  <dt></dt>  
<dd class="notedate">Posted on July 12, 2015  20:32 (UTC)</dd>  <dd class="notedate">Posted on July 12, 2015  20:32 (UTC)</dd>  
Line 99:  Line 91:  
<dd class="note">  <dd class="note">  
Random selections including negative numbers can be obtained via:  Random selections including negative numbers can be obtained via:  
+  <code>_Xrnd = round(random 200) 100;</code>  
−  
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) 
−  x = floor(random 5) will return 0,1,2,3 or 4. (uniform distribution, all numbers have the same probability of being selected)  +  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  +  x = [[ceil]] ([[random]] 5) will return 0, 1, 2, 3, 4 or 5. (0 is very unlikely, but possible, as ceil 0 is 0)</code> 
</dd>  </dd>  
+  
<dd class="notedate">Posted on July 22, 2018  12:58 (UTC+2)</dd>  <dd class="notedate">Posted on July 22, 2018  12:58 (UTC+2)</dd>  
<dt class="note">[[User:Lou MontanaLou Montana]]</dt>  <dt class="note">[[User:Lou MontanaLou Montana]]</dt>  
<dd class="note">  <dd class="note">  
−  {  +  { class="wikitable" 
−  +  + Repartition comparison  
! Formula  ! Formula  
! 0  ! 0  
Line 125:  Line 118:  
! 8  ! 8  
! 9  ! 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%  
−  +  }  
</dd>  </dd>  
+  
</dl>  </dl> 
Revision as of 19:54, 17 July 2021
Description
 Description:
 Random real (floating point) value from 0 (inclusive) to x (not inclusive).
1.56 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)
1.68 two alternative syntaxes are available: allowing to generate seedbased random number based on provided seed (Alternative Syntax 2)
 generating seedbased 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)
 Groups:
 Math
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  an integer. Any float value will be truncated (e.g 0.9, 0.1, 0.1 or 0.9 will be read as 0)
 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  texture position (not a Perlin noise)
 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
 See also:
 selectRandomselectRandomWeighted
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
 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
 Operation Flashpoint: Elite: Scripting Commands
 ArmA: Armed Assault: Scripting Commands
 Arma 2: Scripting Commands
 Arma 2: Operation Arrowhead: Scripting Commands
 Take On Helicopters: Scripting Commands
 Arma 3: Scripting Commands
 Command Group: Math