R/covlyz.R

In dmm: Dyadic Mixed Model for Pedigree Data

covlyz <-
function(cyz, y, z){
# covlyz() - covariance of log y and log z
# clyz <- log(1 + cyz/(y*z))
  tol <- 1.e-8
  ccp <- 1 + cyz/(y*z)
  if(!is.na(ccp)) {
    if(ccp < tol) {
  #   clyz <- log(tol)
      clyz <- ccp -1
    }
    else {
      clyz <- log(ccp)
    }
  }
  else {
    clyz <- NA
  }
  return(clyz)
}