\name{drkpk}
\alias{sspdsty}
\alias{mspdsty}
\alias{msphzd}
\title{Numerical Engine for ssden and sshzd}
\description{
    Calculate penalized likelihood density estimates and hazard
    estimates via the Newton iteration and evaluate the cross-validation
    score, as implemented in the RATFOR routine \code{dnewton.r} and
    \code{hzdnewton.r}, and minimize the cross-validation score using
    \code{\link{nlm}} and \code{\link{nlm0}}.
}
\usage{
sspdsty(s,r,q,cnt,qd.s,qd.r,qd.wt,prec,maxiter,alpha)
mspdsty(s,r,q,cnt,qd.s,qd.r,qd.wt,prec,maxiter,alpha)

msphzd(s,r,q,Nobs,cnt,qd.s,qd.r,qd.wt,prec,maxiter,alpha)
}
\details{
    \code{sspdsty} is used by \code{\link{ssden}} to compute
    cross-validated density estimate with a single smoothing
    parameter. \code{mspdsty} is used by \code{\link{ssden}} to compute
    cross-validated density estimate with multiple smoothing
    parameters.

    \code{msphzd} is used by \code{\link{sshzd}} to compute
    cross-validated hazard estimate with single or multiple smoothing
    parameters.
}
\arguments{
    \item{s}{Fixed effects evaluated at data points.}
    \item{r}{Basis of random effects evaluated at data points.}
    \item{q}{Penalty matrix.}
    \item{Nobs}{Total number of lifetime observations.}
    \item{cnt}{Bin-counts for histogram data.}
    \item{qd.s}{Fixed effects evaluated at quadrature nodes.}
    \item{qd.r}{Basis of random effects evaluated at quadrature nodes.}
    \item{qd.wt}{Quadrature weights.}
    \item{prec}{Precision requirement for internal iterations.}
    \item{maxiter}{Maximum number of iterations allowed for
        internal iterations.}
    \item{alpha}{Parameter defining cross-validation score for smoothing
        parameter selection.}
}
\references{
    Gu, C. and Wang, J. (2002), \emph{Penalized Likelihood Density
    Estimation: Direct Cross-Validation and Scalable Approximation}.
    Available at \url{stat.purdue.edu/~chong/manu.html}.

    Gu, C. (2002), \emph{Smoothing Spline ANOVA Models}.  New York:
    Springer-Verlag.
}
\keyword{smooth}