[R-pkg-devel] Change in normal random numbers between R 3.5.3 and R 3.6.0

[Ulrike Grömping]

Dear R package authors,

I am currently struggling with differences in test results between R 
versions 3.5.3 and 3.6.0: There are expected ones (from the new behavior 
of sample(), which can be switched off by 
RNGkind(sample.kind="Rounding")) and unexpected ones: The normal random 
numbers from a call "y <- rnorm(36)" have changed between R versions, in 
spite of working with a seed. Consequently, most other outcomes change 
as well, as they depend on those random numbers.

Does anyone have an idea what this behavior results from ? You see 
samples below (ignore the first columns, these can be made alike by 
changing sample.kind; but the normal random numbers in the last column 
were the bottom ones before version 3.6.0 and are the top ones afterwards.

>
> < 1 200 10 -25 -2.07823754
> < 2 150 30 25 0.48522682
> < 3 200 20 -25 0.69676878
>
> ...
>
> > 1 250 10 -15 -0.820426525
> > 2 200 10 -25 -1.238082813
> > 3 100 10 15 -1.199567511
...

Can anyone explain, why this is the case, or how I could possibly 
circumvent it (for some noLD checks)?

Best regards,

Ulrike

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## Beuth University of Applied Sciences Berlin
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