# [Rd] nmath bug (PR#762)

**spoon@hilbert.maths.utas.edu.au
**
spoon@hilbert.maths.utas.edu.au

*Fri, 8 Dec 2000 08:29:51 +0100 (MET)*

Hi,
I've been playing with the standalone math library (R.1.1.1,
Redhat 7 i386), and have detected a problem with rpois.
Basically, the rejection step in rpois can result in an infinite loop.
The simplest thing I can come up with that reproduces the problem is
the following.
#include <stdio.h>
#include <math.h>
#include <time.h>
#define MATHLIB_STANDALONE
#include "Mathlib.h"
int main() {
double d;
set_seed(976259805U,2968367341U);
for(long k=0; k<10; k++) {
for(long k=0; k<10000; k++) d = rpois(4500);
for(long k=0; k<250000; k++) d = rpois(100);
printf(".");
fflush(stdout);
}
}
Fro me this prints 3 dots and then hangs.
I realize calling rpois with means this large is probably not the
wisest thing to do, nevertheless, I still consider the infinite loop
to be a bug, hence this report.
Sorry that I cannot give a simpler example than this, its taken me
quite a while to get this far, and as my debugging efforts were going
nowhere, I thought it better to throw it out to the wider community.
Simon
--
*****************************************************************
* Simon Wotherspoon _--_|\ *
* Maths Dept, University of Tasmania / Aus \ *
* Tasmania, Australia \_.--._/ *
* spoon@hilbert.maths.utas.edu.au v *
*****************************************************************
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