{smcl} {* Help file for -setrngseed-, version 2, Oct, 1, 2010}{...} {hline} help for {hi:setrngseed} {hline} {title:Set random-number seed using random integer from random.org} {p 8 17 2} {cmd:setrngseed} [{cmd:,} {it:options}] {col 9}{it:options}{col 30}description {col 8}{hline 60} {col 9}{it:none}{col 30}set seed {col 9}{cmdab:v:erify}{col 30}set seed, but first verify random.org working {col 9}{cmdab:q:uery}{col 30}do not set seed; report random.org quota {col 9}{cmdab:noset:seed}{col 30}do not set seed, report it instead {col 8}{hline 60} {title:Description} {p 4 4 2} Typing {cmd:setrngseed} without arguments is an alternative to using Stata's {help set seed} command. {cmd:setrngseed} obtains truely random integers from {browse "www.random.org"} and uses those results to set the seed of Stata's pseudo-random-number generator. {p 4 4 2} 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. {p 4 4 2} {cmd:setrngseed} is usually used without any options being specified. {title:Options} {p 4 8 2} {cmd:verify} specifies that before setting the seed, {cmd:setrngseed} verify that www.random.org is working as {cmd:setrngseed} expects. This involves obtaining two rather than one random number and so consumes your 24-hour quota more quickly. {p 8 8 2} www.random.org is a separate organization from www.stata.com, and thus they could change the way their site operates. When option {cmd:verify} is specified, {cmd:setrngseed} requests two random numbers and verifies that they are different from each other. {p 4 8 2} {cmd: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. {p 4 8 2} {cmd:nosetseed} does not set the random-number seed. It instead reports the seed that would have been set. {cmd:nosetseed} is used in debugging {cmd:setrngseed}. {title:Remarks} {p 4 4 2} {cmd:setrngseed} sets the Stata's random-number {help set seed:seed} randomly based on measurements of atmospheric noise obtained from the website {browse "www.random.org"}. {p 4 4 2} As of September 30, 2010, {browse "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. {cmd: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 {browse "http://www.random.org":website}. {p 4 4 2} {cmd:setrngseed} will very likely break if {browse www.random.org} changes the protocol for obtaining random numbers. If {cmd:setrngseed} fails repeatedly, please send the the authors email, but only after checking your current random-bit allowance with {cmd:setrngseed, query}. {title:Methods and formulas} {p 4 4 2} 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. {title:Saved results} {pstd} {cmd:setrngseed} saves the following in {cmd:r()}: {synoptset 15 tabbed}{...} {p2col 5 15 19 2: Scalars}{p_end} {synopt:{cmd:r(seed)}}value returned by the web service (only if {cmd:query} has not been specified){p_end} {synopt:{cmd:r(quota)}}your current IP's quota (only if {cmd:query} has been specified){p_end} {p2colreset}{...} {title:Authors} {p 4 4 2} Antoine Terracol, Université Paris 1 {break}terracol@univ-paris1.fr {p 4 4 2} William Gould, StataCorp{break}wgould@stata.com {title:Also see} {p 4 4 2} Manual: {hi:[R] set seed}, {hi:[D] generate} {p_end} {p 4 4 2} Online: help for {help set seed}, {help random numbers} {p_end}