Hi all, I recently noticed that `qnbinom()` can take a long time to calculate a result if the `size` argument is very small. For example qnbinom(0.5, mu = 3, size = 1e-10) takes ~30 seconds on my computer.
I used gdb to step through the qnbinom.c implementation and noticed that in line 106 (https://github.com/wch/r-source/blob/f8d4d7d48051860cc695b99db9be9cf439aee743/src/nmath/qnbinom.c#L106) `y` becomes a very large negative number. Later in the function `y` is (as far as I can see) only used as input for `pnbinom()` which is why I would assume that it should be a non-negative integer. I was wondering if this behavior could be considered a bug and should be reported on the bugzilla? I read the instructions at https://www.r-project.org/bugs.html and wasn't quite sure, so I decided to ask here first :) Best, Constantin PS: I tested the code with R 4.0.0 on macOS and the latest unstable version using docker (https://github.com/wch/r-debug). The session info is > sessionInfo() R Under development (unstable) (2020-08-06 r78973) Platform: x86_64-pc-linux-gnu (64-bit) Running under: Ubuntu 20.04 LTS Matrix products: default BLAS: /usr/local/RD/lib/R/lib/libRblas.so LAPACK: /usr/local/RD/lib/R/lib/libRlapack.so locale: [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C [3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8 [5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8 [7] LC_PAPER=en_US.UTF-8 LC_NAME=C [9] LC_ADDRESS=C LC_TELEPHONE=C [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C attached base packages: [1] stats graphics grDevices utils datasets methods base loaded via a namespace (and not attached): [1] compiler_4.1.0 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
