[R] Getting different results with set.seed()

[Eric Berger]

In that case, another interesting test would be to check whether the
problem exists when you don't use doParallel().


On Thu, Aug 19, 2021 at 2:28 PM Shah Alam <dr.alamsolangi using gmail.com> wrote:
>
> Dear All,
>
> Thanks a lot for your valuable suggestions. I am going to implement one by
> one.
>
> Jan:
>
> Yes, I am using the "doParallel" package for parallelization. I will let
> you know the results after implementing all the given suggestions.
>
> Best regards,
> Shah
>
>
>
> On Thu, 19 Aug 2021 at 11:57, Jan van der Laan <rhelp using eoos.dds.nl> wrote:
>
> >
> >
> > What you could also try is check if the self coded functions use the
> > random generator when defining them:
> >
> > starting_seed <- .Random.seed
> >
> > Step 1. Self-coded functions (these functions generate random numbers as
> > well)
> >
> > # check if functions have modified the seed:
> > all.equal(starting_seed, .Random.seed)
> >
> > Step 2: set.seed (123)
> >
> >
> >
> > What has also happened to me is that some of the functions I called had
> > their own random number generator independent of that of R. For example
> > using one in C/C++.
> >
> > Do your functions do stuff in parallel? For example using the parallel
> > or snow package? In that case you also have to set the seed in the
> > parallel workers.
> >
> > Best,
> > Jan
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > On 19-08-2021 11:25, PIKAL Petr wrote:
> > > Hi
> > >
> > > Did you try different order?
> > >
> > > Step 2: set.seed (123)
> > >
> > > Step 1. Self-coded functions (these functions generate random numbers as
> > well)
> > >
> > > Step 3: Call those functions.
> > >
> > > Step 4: model results.
> > >
> > > Cheers
> > > Petr.
> > >
> > > And BTW, do not use HTML formating, it could cause problems in text only
> > list.
> > >
> > >
> > > From: Shah Alam <dr.alamsolangi using gmail.com>
> > > Sent: Thursday, August 19, 2021 10:10 AM
> > > To: PIKAL Petr <petr.pikal using precheza.cz>
> > > Cc: r-help mailing list <r-help using r-project.org>
> > > Subject: Re: [R] Getting different results with set.seed()
> > >
> > > Dear Petr,
> > >
> > > It is more than 2000 lines of code with a lot of functions and data
> > inputs. I
> > > am not sure whether it would be useful to upload it. However, you are
> > > absolutely right. I used
> > >
> > > Step 1. Self-coded functions (these functions generate random numbers as
> > well)
> > >
> > > Step 2: set.seed (123)
> > >
> > > Step 3: Call those functions.
> > >
> > > Step 4: model results.
> > >
> > > I close the R session and run the code from step 1. I get different
> > results
> > > for the same set of values for parameters.
> > >
> > > Best regards,
> > > Shah
> > >
> > >
> > >
> > >
> > > On Thu, 19 Aug 2021 at 09:56, PIKAL Petr <mailto:petr.pikal using precheza.cz>
> > > wrote:
> > > Hi
> > >
> > > Please provide at least your code preferably with some data to reproduce
> > > this behaviour. I wonder if anybody could help you without such
> > information.
> > >
> > > My wild guess is that you used
> > >
> > > set.seed(1234)
> > >
> > > some code
> > >
> > > the code used again
> > >
> > > in which case you have to expect different results.
> > >
> > > Cheers
> > > Petr
> > >
> > >> -----Original Message-----
> > >> From: R-help <mailto:r-help-bounces using r-project.org> On Behalf Of Shah
> > Alam
> > >> Sent: Thursday, August 19, 2021 9:46 AM
> > >> To: r-help mailing list <mailto:r-help using r-project.org>
> > >> Subject: [R] Getting different results with set.seed()
> > >>
> > >> Dear All,
> > >>
> > >> I was using set.seed to reproduce the same results for the discrete
> > event
> > >> simulation model. I have 12 unknown parameters for optimization (just a
> > >> little background). I got a good fit of parameter combinations. However,
> > >> when I use those parameters combinations again in the model. I am
> > getting
> > >> different results.
> > >>
> > >> Is there any problem with the set.seed. I assume the set.seed should
> > >> produce the same results.
> > >>
> > >> I used set.seed(1234).
> > >>
> > >> Best regards,
> > >> Shah
> > >>
> > >>        [[alternative HTML version deleted]]
> > >>
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> > >> guide.html
> > >> and provide commented, minimal, self-contained, reproducible code.
> > >>
> > >> ______________________________________________
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> >
> > ______________________________________________
> > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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> >
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.