[Rd] Development version of R fails tests and is not installed

[Martin Maechler]

>>>>> Berwin A Turlach 
>>>>>     on Tue, 5 Mar 2019 16:54:09 +0800 writes:

    > G'day all,
    > I have daily scripts running to install the patched version of the
    > current R version and the development version of R on my linux box
    > (Ubuntu 18.04.2 LTS).

    > The last development version that was successfully compiled and
    > installed was "R Under development (unstable) (2019-02-25 r76159)" on
    > 26 February.  Since then the script always fails as a regression test
    > seems to fail.  Specifically, in the tests/ subdirectory of my build
    > directory I have a file reg-tests-1d.Rout.fail which ends with:

    >> ## checking ar.yw.default() multivariate case
    >> estd <- ar(unclass(y) , aic = FALSE, order.max = 2) ## Estimate VAR(2)
    >> es.d <- ar(unclass(y.), aic = FALSE, order.max = 2, na.action=na.pass)
    >> stopifnot(exprs = {
    > +     all.equal(est$ar[1,,], diag(0.8, 2), tol = 0.08)# seen 0.0038
    > +     all.equal(est[1:6], es.[1:6], tol = 5e-3)
    > +     all.equal(estd$x.mean, es.d$x.mean, tol = 0.01) # seen 0.0023
    > +     all.equal(estd[c(1:3,5:6)],
    > +               es.d[c(1:3,5:6)], tol = 1e-3)## seen {1,3,8}e-4
    > +     all.equal(lapply(estd[1:6],unname),
    > +               lapply(est [1:6],unname), tol = 2e-12)# almost identical
    > +     all.equal(lapply(es.d[1:6],unname),
    > +               lapply(es. [1:6],unname), tol = 2e-12)
    > + })
    > Error: lapply(es.d[1:6], unname) and lapply(es.[1:6], unname) are not equal:
    > Component "aic": Mean relative difference: 3.297178e-12
    > Execution halted

    > Would it be possible to make this tolerance more lenient?  In case it
    > matters, I am configuring R to be compiled using Openblas and this test
    > fails for the 64 bit installation, the 32 bit installation seems to
    > pass all tests.

Interesting. But we had another report (on this mailing list!) by
Er. Ho., also using OpenBLAS, but then in combination with Cygwin.
After Cygwin related problems were solved, on March 1 he said

> I have an error at reg-1d.  It stops the process.  However, the mean difference
> (as per the file) is 2.0e-12. 

and when I asked him to be more precise.. he wasn't but did
"solve" the problem by changing the test file.
Now we know from you Berwin (thank you for providing the details!)
what it has been.

==> I could investigate and -- lo and behold! --  the solution
is probably the fact that the RNGkind(sample.kind = *) was
introduced *and* the default was to differ from previous
versions of R.

    > Happy to provide any more information/context that might be needed.

Can you please try adding

    suppressWarnings(RNGversion("3.5.0"))

e.g. at the very beginning of the   tests/reg-tests-1d.R
file or just a few lines above the code you show above,
replace in line 1470

	set.seed(42)
by
	set.seed(42); suppressWarnings(RNGversion("3.5.0"))

It will use a different missingness pattern for that
multivariate AR example, i.e., different data.

Best, Martin