Hi!
I hit this problem while working on updating math/R from version
2.15.3 to the latest version (3.0.2).
It started happening since upstream switched from double functions
to C99 long double functions (expl, fabsl, ...), during the R-3
development cycle.
Take the following reduced test-case, adapted from what R's code
does:
---8<---
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main(void) {
double theta = 1;
long double lambda, pr, pr2;
lambda = (0.5*theta);
pr = exp(-lambda);
pr2 = expl(-lambda);
printf("theta == %g, pr == %Lg, pr2 == %Lg\n", theta, pr, pr2);
exit(0);
}
---8<---
This produces the following output on Linux (x86_64):
theta == 1, pr == 0.606531, pr2 == 0.606531
While on OpenBSD -current amd64:
theta == 1, pr == 0.606531, pr2 == nan
And indeed R-3's testsuite fails with the error message
"NaNs produced":
Warning in pchisq(1e-300, df = 0, ncp = lam) : NaNs produced
> stopifnot(all.equal(p00, exp(-lam/2)),
+ all.equal(p.0, exp(-lam/2)))
Error: all.equal(p.0, exp(-lam/2)) is not TRUE
Execution halted
Is this a bug in our expl() ?
Ciao,
David
