These functions provide information about the generalized Weibull
distribution, also called the exponentiated Weibull, with scale
parameter equal to m, shape equal to s, and family
parameter equal to f: log hazard.
(See `rmutil` for the d/p/q/r boxcox functions density,
cumulative distribution, quantiles, and random generation).
The generalized Weibull distribution has density
$$
f(y) = \frac{\sigma \nu y^{\sigma-1} (1-\exp(-(y/\mu)^\sigma))^{\nu-1}
\exp(-(y/\mu)^\sigma)}{\mu^\sigma}$$
where \(\mu\) is the scale parameter of the distribution,
\(\sigma\) is the shape, and \(\nu\) is the family
parameter.
\(\nu=1\) gives a Weibull distribution, for
\(\sigma=1\), \(\nu<0\) a generalized F distribution,
and for \(\sigma>0\), \(\nu\leq0\) a Burr type XII distribution.