% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/estpw_d_matrix_cali.R
\name{compute_D_raking}
\alias{compute_D_raking}
\title{Compute design-based covariance matrix D for calibration}
\usage{
compute_D_raking(sp_des, Xp)
}
\arguments{
\item{sp_des}{A survey design object of class `"survey.design2"` or
`"svyrep.design"`.}

\item{Xp}{Numeric matrix of dimension `n_p x p`. Each row is the
covariate vector `x_j` used in the calibration estimating equation.}
}
\value{
A `p x p` covariance matrix `D`.
}
\description{
Internal helper to compute
\deqn{D = Var_p\left( \sum_{j \in s_p} d_j x_j \right)}
from an existing survey design object created by
survey::svydesign() or survey::svrepdesign().
}
\details{
In the raking ratio calibration method, the probability sample
contribution in the estimating equation is \eqn{d_j x_j}, so the
design-based covariance matrix is obtained by treating
\eqn{h_j = x_j} as the survey total variable.
}
\keyword{internal}
