## PR#4582 %*% with NAs
stopifnot(is.na(NA %*% 0), is.na(0 %*% NA))
## depended on the BLAS in use.


## found from fallback test in slam 0.1-15
## most likely indicates an inaedquate BLAS.
x <- matrix(c(1, 0, NA, 1), 2, 2)
y <- matrix(c(1, 0, 0, 2, 1, 0), 3, 2)
(z <- tcrossprod(x, y))
stopifnot(identical(z, x %*% t(y)))
stopifnot(is.nan(log(0) %*% 0))
## depended on the BLAS in use: some (including the reference BLAS)
## had z[1,3] == 0 and log(0) %*% 0 as as.matrix(0).