Hi,
I came across a case when the dimensions of matrices returned by qr()
operated on a sparse matrix does not coincide with the initial matrix.
Here is a spinet code that should produce an example (one of many that I could provide):
?m=205
?n=199
?set.seed(7);
?a=matrix(rnorm(m*n), m, n)
?a[sample(seq(m*n), m*(n-4))]=0
?a=as(a, "Matrix")
?qa=qr(a);
?stopifnot(nrow(qa at R) == m)
?# On my box I have nrow(qa at R):=207 while should be 205 as m is)
Note that for m=203 and n=197, the same code produce right (i.e. coinciding) dimensions.
Have I missed something?
Serguei.
> R.version
platform?????? x86_64-pc-linux-gnu
arch?????????? x86_64
os???????????? linux-gnu
system???????? x86_64, linux-gnu
status
major????????? 3
minor????????? 4.3
year?????????? 2017
month????????? 11
day??????????? 30
svn rev??????? 73796
language?????? R
version.string R version 3.4.3 (2017-11-30)
nickname?????? Kite-Eating Tree