Difference between revisions of "Rn2"
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{{DISPLAYTITLE:rn2}} | {{DISPLAYTITLE:rn2}} | ||
{{randomvariable|name=rn2(x)|graph=rn2.svg|caption=[[wikipedia:Probability mass function|Probability mass function]] of rn2(10).|distribution=[[Wikipedia:discrete uniform distribution|uniform]]|mean=<math>(x-1)/2</math>|stddev=<math>\sqrt{(x^2-1)/12}</math>}} | {{randomvariable|name=rn2(x)|graph=rn2.svg|caption=[[wikipedia:Probability mass function|Probability mass function]] of rn2(10).|distribution=[[Wikipedia:discrete uniform distribution|uniform]]|mean=<math>(x-1)/2</math>|stddev=<math>\sqrt{(x^2-1)/12}</math>}} | ||
| − | rn2(x)<ref>{{function|rnd.c|rn2}}</ref> is a pseudo-random number function used in NetHack when a result should be unweighted. The range of values is between 0 and x-1 inclusive (that is, 0 | + | rn2(x)<ref>{{function|rnd.c|rn2}}</ref> is a pseudo-random number function used in NetHack when a result should be unweighted. The range of values is between 0 and x-1 inclusive (that is, 0 ≤ rn2(x) < x). |
For example, to simulate a percentage chance: | For example, to simulate a percentage chance: | ||
if (rn2(100) < chance) { ... } | if (rn2(100) < chance) { ... } | ||
| + | |||
| + | Also, | ||
| + | !rn2(x) | ||
| + | is true with a 1/x probability. | ||
See also [[rn1]]. | See also [[rn1]]. | ||
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<references/> | <references/> | ||
| − | |||
[[Category:Random number functions]] | [[Category:Random number functions]] | ||
Revision as of 15:31, 11 July 2015
| rn2(x) | |
|---|---|
 Probability mass function of rn2(10). | |
| Distribution | uniform |
| Mean | 
|
| Standard deviation | 
|
rn2(x)[1] is a pseudo-random number function used in NetHack when a result should be unweighted. The range of values is between 0 and x-1 inclusive (that is, 0 ≤ rn2(x) < x).
For example, to simulate a percentage chance:
if (rn2(100) < chance) { ... }
Also,
!rn2(x)
is true with a 1/x probability.
See also rn1.
