... 
Optional arguments to be passed to the particular random number
generating function (cf. below).
@details
rho[["distribution"]] :
The follwing table shows the available distributions and the implemented generation method:
rho[["distribution"]]  Distribution Name  method 
"const"  Deterministic case  not applicable 
"norm"  Normal  calculate , fit 
"posnorm"  Positive normal  calculate , fit 
"tnorm_0_1"  01truncated normal  calculate , fit 
"beta"  Beta  fit 
"cauchy"  Cauchy  fit 
"logis"  Logistic  fit 
"t"  Student t  fit 
"chisq"  Central ChiSquared  fit 
"chisqnc"  Noncentral ChiSquared  fit 
"exp"  Exponential  fit 
"f"  Central F  fit 
"gamma"  Gamma with scale=1/rate  fit 
"lnorm"  Log Normal  calculate , fit 
"unif"  Uniform  calculate , fit 
"weibull"  Weibull  fit 
"triang"  Triangular  fit 
"gompertz"  Gompertz  fit 
"pert"  (Modified) PERT  fit 

For distribution="const" the argument method is obsolete, as a constant is neither
fitted nor calculated.
rho[["method"]] 
If supplied, i.e. !is.null(rho[["method"]]) , this value overwrites the function
argument method .
method 
This parameter defines, how the parameters of the distribution to be sampled are derived from
rho[["lower"]] , rho[["upper"]] and possibly rho[["median"]] .
Possibilities are "calculate" (the default) or "fit" :
method="calculate" 
The parameters are calculated if possible using the exact (analytical) formula or, otherwise,
numerically. This calculation of the distribution parameters is independent of
rho[["median"]] being supplied or not. For the implemented distributions, it only
depends on rho[["lower"]] and rho[["upper"]] . However, if it is supplied, i.e.
is.numeric(rho[["median"]]) , a check is performed, if the relative deviation of the
generated median from rho[["median"]] is greater than relativeTolerance . In
this case a warning is given.
method="fit" 
The parameters are obtained by fitting the distribution on the supplied quantiles.
Given that rho[["median"]]==NULL the distribution is fitted only to lower and
upper and a warning is given; due to the used numerical procedure, the calculated
parameters might define a distribution which strongly deviates from the intended one. There is
larger control on the shape of the distribution to be generated by supplying the estimate of the
median. If is.numeric(rho[["median"]]) the distribution is fitted to lower ,
upper and median .
... 
For passing further parameters to the function which generates the random numbers, cf.
the above table and follow the link in the column method .
