vector of function parameters with:
p[1] determines the offset before increase ofs = (p[4]+1) * (1-p[1]),
p[2] inflexion point of increasing branch,
p[3] steepness of increasing branch,
p[4] offset after the peak,
p[5] inflexion point of decreasing branch,
p[6] steepness of decreasing branch,
lower
lower limit of the cumulative (integrated) function,
upper
upper limit of the cumulative (integrated) function.
Details
The six-parametric Weibull function is more flexible than the four-parametric
version. It is possible to have different offsets before and after the peak.
The function can be given by:
fweibull6 gives the function and aweibull6 its definite
integral (cumulative function or area under curve). Note that
in contrast to aweibull4, the integral is
solved numerically and that the function returns a scalar, not a vector.