% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/get_B.R
\name{.extract_G_diagonal}
\alias{.extract_G_diagonal}
\title{Extract Per-Partition Diagonal Blocks from a Full Matrix}
\usage{
.extract_G_diagonal(M, p_expansions, K)
}
\arguments{
\item{M}{A \eqn{P \times P} matrix where \eqn{P = p\_expansions \times (K+1)}.}

\item{p_expansions}{Integer; number of basis terms (columns) per partition.}

\item{K}{Integer; number of interior knots.}
}
\value{
A list of length \eqn{K+1}, each element a
  \eqn{p\_expansions \times p\_expansions} matrix corresponding to the
  diagonal block for partition \eqn{k}.
}
\description{
Given a \eqn{P \times P} matrix (e.g., the full-system
\eqn{\mathbf{G} = (\mathbf{X}^{\top}\mathbf{V}^{-1}\mathbf{X} +
\boldsymbol{\Lambda})^{-1}}), extracts the \eqn{p \times p} diagonal
block for each of the \eqn{K+1} partitions.
}
\keyword{internal}
