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

[Berwin A Turlach]

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.

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

Cheers,

	Berwin