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help for setrngseed                                
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Set random-number seed using random integer from random.org

        setrngseed [, options]


        options              description
       ------------------------------------------------------------
        none                 set seed

        verify               set seed, but first verify random.org working

        query                do not set seed; report random.org quota
        nosetseed            do not set seed, report it instead
       ------------------------------------------------------------


Description

    Typing setrngseed without arguments is an alternative to using Stata's 
    set seed command.  setrngseed obtains truely random integers from 
    www.random.org and uses those results to set the seed of Stata's
    pseudo-random-number generator.

    www.random.org will currently deliver roughly 32,000 seeds per 24-hour
    period.  You can visit www.random.org and purchase additional random
    numbers should you need them, which is unlikely, or to make a donation in
    support of their efforts.

    setrngseed is usually used without any options being specified.


Options

    verify specifies that before setting the seed, setrngseed verify that
        www.random.org is working as setrngseed expects.  This involves
        obtaining two rather than one random number and so consumes your
        24-hour quota more quickly.

        www.random.org is a separate organization from www.stata.com, and
        thus they could change the way their site operates.  When option
        verify is specified, setrngseed requests two random numbers and
        verifies that they are different from each other.

    query does not set the random-number seed.  It instead reports the number
        of seeds www.random.org would supply remaining in your 24-hour quota.

    nosetseed does not set the random-number seed.  It instead reports the
        seed that would have been set.  nosetseed is used in debugging
        setrngseed.


Remarks

    setrngseed sets the Stata's random-number seed randomly based on
    measurements of atmospheric noise obtained from the website 
    www.random.org.

    As of September 30, 2010, www.random.org has a quota system in which each
    IP address starts off with a quota of 1,000,000 random bits which is
    topped off with up to 200,000 bits each 24-hour period.  setrngseed uses
    31 bits each time it sets Stata's random-number seed, so your quota
    starts off with approximately 32,258 seeds and is topped off with up to
    6,451 seeds per day.  Additional random bits can be purchased through the
    website.


    setrngseed will very likely break if www.random.org changes the protocol
    for obtaining random numbers.  If setrngseed fails repeatedly, please
    send the the authors email, but only after checking your current
    random-bit allowance with setrngseed, query.


Methods and formulas

    A random integer between -1,000,000,000 and +1,000,000,000 is obtained
    from random.org, 1,000,000,000 is added to it, and that number is used to
    set the random-number seed.


Saved results

    setrngseed saves the following in r():

    Scalars   
      r(seed)        value returned by the web service (only if query has not
                       been specified)
      r(quota)       your current IP's quota (only if query has been
                       specified)


Authors

    Antoine Terracol, Université Paris 1
    terracol@univ-paris1.fr

    William Gould, StataCorp
    wgould@stata.com



Also see

    Manual: [R] set seed, [D] generate

    Online: help for set seed, random numbers