R/f_sum.R

In jeff-goldsmith/vbvs.concurrent: Variational Bayes Variable Selection for the Functional Linear Concurrent Model

#' Sum computation 1
#' 
#' Internal function used compute a sum in FPCA-based covariance updates
#' 
#' @param mu.q.c current value of mu.q.c
#' @param sig.q.c current value of sig.q.c
#' @param theta spline basis
#' @param subj.id vector of subject IDs
#' 
#' @author Jeff Goldsmith \email{ajg2202@@cumc.columbia.edu}
#' 
f_sum = function(mu.q.c, sig.q.c, theta, subj.id){
  I = dim(mu.q.c)[1]
  kp = dim(mu.q.c)[2]
  kt = dim(theta)[1]
  ret.sum = matrix(0, kp*kt, kp*kt)
  subjs = unique(subj.id)
  
  for(i in 1:I){
    index = which(subj.id == subjs[i])
    
    mu.mat = matrix(mu.q.c[i,], nrow = 1, ncol = kp)
    ret.sum = ret.sum + kronecker(t(mu.mat) %*% mu.mat + sig.q.c[[i]], (theta[,index])%*%t(theta[,index])) 
  }
  return(ret.sum)
}