gnm_float
pgumbel (gnm_float x, gnm_float mu, gnm_float beta, gboolean lower_tail, gboolean log_p)
{
gnm_float z, lp;
if (!(beta > 0) || gnm_isnan (mu) || gnm_isnan (beta) || gnm_isnan (x))
return gnm_nan;
z = (x - mu) / beta;
lp = -gnm_exp (-z);
if (lower_tail)
return log_p ? lp : gnm_exp (lp);
else
return log_p ? swap_log_tail (lp) : 0 - gnm_expm1 (lp);
}
gnm_float
qcauchy (gnm_float p, gnm_float location, gnm_float scale,
gboolean lower_tail, gboolean log_p)
{
if (gnm_isnan(p) || gnm_isnan(location) || gnm_isnan(scale))
return p + location + scale;
R_Q_P01_check(p);
if (scale < 0 || !gnm_finite(scale)) ML_ERR_return_NAN;
if (log_p) {
if (p > -1)
/* The "0" here is important for the p=0 case: */
lower_tail = !lower_tail, p = 0 - gnm_expm1 (p);
else
p = gnm_exp (p);
}
if (lower_tail) scale = -scale;
return location + scale / gnm_tan(M_PIgnum * p);
}
