pdMatrix.pdSRM: Extract Matrix or Square-Root Factor from a pdSRM Object

In roundRobinR: Manipulate and Analyze Round Robin Dyadic Data

Extract Matrix or Square-Root Factor from a pdSRM Object

Description

Internal method called by pdMatrix to reconstruct the full covariance matrix from the three stored SRM parameters (actor SD, partner SD, actor-partner correlation).

Usage

## S3 method for class 'pdSRM'
pdMatrix(object, factor = FALSE)

Arguments

object	an object inheriting from pdSRM
factor	logical; if TRUE the upper Cholesky factor is returned, otherwise the full positive-definite matrix

Value

if factor is FALSE, the positive-definite matrix represented by object; if TRUE, an upper triangular Cholesky factor with a logDet attribute

Examples

d <- createDummies(
  group.id = "groupId", act.id = "actId", part.id = "partId",
  d = sampleDyadData[sampleDyadData$timeId == 1, ],
  merge.original = TRUE
)
o <- nlme::lme(
  liking ~ 1,
  random = list(groupId = nlme::pdBlocked(list(
    nlme::pdIdent(~1),
    pdSRM(~ -1 + a1 + a2 + a3 + a4 + p1 + p2 + p3 + p4)
  ))),
  correlation = nlme::corCompSymm(form = ~1 | groupId / pdSRM_dyad_id),
  data = d,
  na.action = stats::na.omit
)

roundRobinR documentation built on Sept. 18, 2026, 1:06 a.m.