The fit_copula_submodel_OrdCont()
function fits the copula (sub)model for a
continuous surrogate and an ordinal true endpoint with maximum likelihood.
fit_copula_submodel_OrdCont(
X,
Y,
copula_family,
marginal_Y,
start_Y,
start_copula,
method = "BFGS",
K,
names_XY = c("Surr", "True"),
twostep = FALSE,
...
)
A list with five elements:
ml_fit: object of class maxLik::maxLik
that contains the estimated copula
model.
marginal_X: list with the estimated cdf, pdf/pmf, and inverse cdf for X.
marginal_Y: list with the estimated cdf, pdf/pmf, and inverse cdf for X.
copula_family: string that indicates the copula family
data: data frame containing X
and Y
names_XY: The names (i.e., "Surr"
and "True"
) for X
and Y
First variable (Ordinal with \(K\) categories)
Second variable (Continuous)
Copula family, one of the following:
"clayton"
"frank"
"gumbel"
"gaussian"
List with the following five elements (in order):
Density function with first argument x
and second argument para
the parameter
vector for this distribution.
Distribution function with first argument x
and second argument para
.
Inverse distribution function with first argument p
and second argument para
.
The number of elements in para
.
Starting values for para
.
Starting values for the marginal distribution paramters for Y
.
Starting value for the copula parameter.
Optimization algorithm for maximizing the objective function.
For all options, see ?maxLik::maxLik
. Defaults to "BFGS"
.
Number of categories in X
.
Names for X
and Y
, respectively.
(boolean) If TRUE
, the starting values are fixed for the
marginal distributions and only the copula parameter is estimated.
Extra argument to pass onto maxLik::maxLik
ordinal_continuous_loglik()