R Under development (unstable) (2023-12-09 r85665 ucrt) -- "Unsuffered Consequences"
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> suppressPackageStartupMessages(library(float))
> set.seed(1234)
> 
> tol = 1e-6
> 
> cmp = function(qr_x, qr_xs)
+ {
+   test = dbl(qr.R(qr_xs))
+   truth = qr.R(qr_x)
+   stopifnot(all.equal(test, truth, tol=tol))
+   
+   test = dbl(qr.Q(qr_xs))
+   truth = qr.Q(qr_x)
+   stopifnot(all.equal(test, truth, tol=tol))
+ 
+   test = dbl(qr.R(qr_xs, complete=TRUE))
+   truth = qr.R(qr_x, complete=TRUE)
+   stopifnot(all.equal(test, truth, tol=tol))
+   
+   test = dbl(qr.Q(qr_xs, complete=TRUE))
+   truth = qr.Q(qr_x, complete=TRUE)
+   stopifnot(all.equal(test, truth, tol=tol))
+ }
> 
> 
> # m > n
> x = matrix(stats::rnorm(30), 10)
> xs = fl(x)
> qr_x = qr(x, LAPACK=TRUE)
> qr_xs = qr(xs)
> 
> stopifnot(identical(qr_xs$rank, 3L))
> cmp(qr_x, qr_xs)
> 
> 
> 
> # NOTE: m < n and rank degenerate cases not well-defined
> 
> proc.time()
   user  system elapsed 
   0.40    0.03    0.42