View source for Ns rand

Man page: http://aolserver.com/docs/tcl/ns_rand.html

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'''NAME'''

: ns_rand - Generate a random number

'''SYNOPSIS'''

: '''ns_rand''' ''?maximum?'' 

'''DESCRIPTION'''

: This command generates a cryptographically secure random number.  If ''maximum'' is not specified, the random number returned is a floating-point value n such that 0.0 <= n < 1.0.  If ''maximum'' is specified, it must be a positive integer between 1 and 2147483647, in which case '''ns_rand''' will return an integer value n such that 0 <= n <= max - 1.

: Internally '''ns_rand''' is implemented with the '''drand48()''' and '''lrand48()''' standard library functions.  An internal random seed is generated the first time '''ns_rand''' is called after the server starts.

'''EXAMPLES'''

    % ns_rand
    0.39938485692

    % ns_rand 10
    7

'''CAVEAT'''

: [ns_rand 1] will always produce the result 0. [ns_rand 2] will produce the desired "coin flip" outcome of 0 or 1. This is standard with [http://java.sun.com/j2se/1.4.2/docs/api/java/util/Random.html#nextInt(int) Java's Random implementation of nextInt] and most other random number libraries.

'''SEE ALSO'''

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[[Category Documentation]] - [[Category Core Tcl API]]