Random seed needed

[Daniel Feenberg]

I am looking for a number or string that will be different in different runs of the same program. So far I can only think of using c(current_time) but that only changes once a minute. Is there a way to get the processid? That is what Stata uses for its temporary files but I don't see how to get it myself. The documentation for Stata random functions suggests saving the rng state, but that requires coordination across runs that I can't depend on. Any other suggestions?

[David Radwin]

If your computer can access the internet, this user-written program will download true random numbers and set them as seeds:

. ssc describe setrngseed

-----------------------------------------------------------------------------------------------------
package setrngseed from http://fmwww.bc.edu/repec/bocode/s
-----------------------------------------------------------------------------------------------------

TITLE
      'SETRNGSEED': module to to set random-number seed using truly random integer from random.org

DESCRIPTION/AUTHOR(S)
      
      Typing setrngseed without arguments is an alternative to using
      Stata's  set seed command.  setrngseed obtains truly random
      integers from  www.random.org and uses those results to set the
      seed of Stata's  pseudo-random-number generator.
      
      KW: random numbers
      KW: seed
      
      Requires: Stata version 10
      
      Distribution-Date: 20101005
      
      Author: Antoine Terracol, Universite Paris I
      Support: email [email protected]
      
      Author: William Gould, StataCorp LP
      Support: email [email protected]
      

INSTALLATION FILES                           (type net install setrngseed)
      setrngseed.ado
      setrngseed.sthlp
-----------------------------------------------------------------------------------------------------

[Mauricio Caceres]

You could pass the current datetime as an argument to Stata and save the PID as a bash variable. In your do file:

args seed
set seed `seed'

And then you can call stata via:

$ stata -b do file.do `date +%s` & PID=`echo $!`

[Tiago Pereira]

Folks, have you found any alternative to the -setrngseed- ?

I have received the following error

.  setrngseed
(contacting http://www.random.org)
file http://www.random.org/integers/?num=1&min=-1000000000&max=1000000000&col=1&base=10&format=plain&rnd=new not found
server says file permanently redirected to https://www.random.org/integers/?num=1&min=-1000000000&max=1000000000&col=1&base=10&format=plain&rnd=new
r(601);

[Leonardo Guizzetti]

This may not get updated officially, but the issue can be resolved by a single find/replace of -http://- with -https://- as the protocols have moved to HTTPS since publication of the command.

1) copy the setrngseed help file and ado to your PERSONAL ado path
2) edit the setrngseed.ado to fix the URLs within
3) uninstall the SSC version (-ado uninstall setrngseed-)
4) verify Stata sees your edited version (-which setrngseed-)
5) test it out (-setrngseed-)

[Tiago Pereira]

Leonardo, brilliant solution! Thank you so much. It helped A LOT!

All the best,
Tiago

[Joro Kolev]

Getting a truly random seed from a outside source as described above is probably a better idea.

But the current time of Stata is measured down to the second, so it changes not every minute, but rather every second.

. dis c(current_date)
11 Aug 2021

. dis c(current_time)
10:42:26

. dis c(current_date)
11 Aug 2021

. dis c(current_time)
10:42:29

. dis c(current_date)
11 Aug 2021

. dis c(current_time)
10:42:31

. dis c(current_date)
11 Aug 2021

. dis c(current_time)
10:42:34

current time changes every second.

[Bjarte Aagnes]

c(current_date) + c(current_time) etc may be combined with process and thread IDs?

java :
    Macro.setLocal​("pid", Long.toString(ProcessHandle.current().pid()));  
    Macro.setLocal​("tid", Long.toString(Thread.currentThread().getId()));  
end

[Bjarte Aagnes]

ref #8:

local end_java end

qui forvalues i = 1/5 {
    
    java :

        String tms = Long.toString(System.currentTimeMillis());
        String pid = Long.toString(ProcessHandle.current().pid());  
        String tid = Long.toString(Thread.currentThread().getId());
        Macro.setLocal​("id", tms + "_" + pid + "_" + tid);
        
    `end_java'

    noi macro dir _id
}

. qui forvalues i = 1/5 {
_id:            1628710362015_18100_948
_id:            1628710362139_18100_956
_id:            1628710362218_18100_964
_id:            1628710362298_18100_972
_id:            1628710362366_18100_980