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

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−  {{  +  {{RVtype=command 
−  
−   ofp =  +  game1= ofp 
+  version1= 1.00  
−  1.00  +  game2= ofpe 
−  +  version2= 1.00  
−    +  game3= arma1 
−  +  version3= 1.00  
−  
−  
−  +  game4= arma2  
+  version4= 1.00  
+  
+  game5= arma2oa  
+  version5= 1.50  
+  
+  game6= tkoh  
+  version6= 1.00  
+  
+  game7= arma3  
+  version7= 0.50  
+  
+  gr1= Math  
+  
+  descr= [[Image:bellcurve.jpgright200px]] Random real (floating point) value from 0 (inclusive) to x (not inclusive).<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}})  
+  * 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}})  
+  
+  s1= [[random]] x  
−  
p1= x: [[Number]]  p1= x: [[Number]]  
−  
−  s2=  +  r1= [[Number]] 
−  p21= [min, mid, max]: [[Array]]  +  
−  p22= min: [[Number]]  +  s2= [[random]] [min, mid, max] {{Sincearma31.56y}} 
−  p23= mid: [[Number]]  +  
−  +  p21= [min, mid, max]: [[Array]]  
−  +  
+  p22= min: [[Number]]  
+  
+  p23= mid: [[Number]]  
−    +  p24= max: [[Number]] 
−  
−  
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−    +  r2= [[Number]] 
−  
−  
−  
−  
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−  +  s3= seed [[random]] x {{Sincearma31.68y}}  
−  
−    
−    +  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]] 
−    +  r3= [[Number]]  Value from 0 to x 
−  +  
−  +  s4= seed [[random]] [x, y] {{Sincearma31.68y}}  
−  +  
−  +  p61= seed: [[Number]]  
+  
+  p62= [x, y]: [[Array]]  texture position (''not'' a Perlin noise)  
−    +  p63= x: [[Number]] 
−  
−  
−  
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−  
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−  
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−  
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−  [[  +  p64= y: [[Number]] 
−  
−  
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−  
−  
−  
−  
−  
−  
−  
−  [[  +  r4= [[Number]]  Value from 0 to 1 
−  
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−  
−  
−  
−  
−  
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−  +  x1= <code>_rNumber = [[random]] 1;</code>  
−  
−  
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−  
−  
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−  
−  
−   [[  +  x2= <code>_rNumber = [[random]] 10;</code> 
−  +  x3= Generate a random position inside a circle (see also [[Example Code: Random Area Distribution]])  
+  <code>_center [[getPos]] [_radius * [[sqrt]] [[random]] 1, [[random]] 360];</code>  
−  <  +  x4= To select random value from an array: 
+  <code>_array = ["apples", "pears", "bananas", "M16"];  
+  _random = _array [[select]] [[floor]] [[random]] [[count]] _array;  
+  {{cc{{Sincearma31.56}}}}  
+  _random = [[selectRandom]] _array;</code>  
−  +  seealso= [[selectRandom]], [[selectRandomWeighted]]  
−  [[  +  }} 
−  [[  
−  
−  
−  
−  
−  
−  
−  
<dl class="command_description">  <dl class="command_description">  
+  
+  <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>  
<dt class="note">[[User:HcpookieHcpookie]]</dt>  <dt class="note">[[User:HcpookieHcpookie]]</dt>  
<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>  <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.  
+  * 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]]:  
+  <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 = [[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 class="notedate">Posted on July 22, 2018  12:58 (UTC+2)</dd>  
−  +  <dt class="note">[[User:Lou MontanaLou Montana]]</dt>  
−  +  <dd class="note">  
−  +  { class="wikitable"  
−  +  + 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%  
+  }  
</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