R/modelLcmmGMM.R

In latrend: A Framework for Clustering Longitudinal Data

#' @include model.R
setClass('lcModelLcmmGMM', contains = 'lcModel')

#' @export
#' @rdname interface-lcmm
#' @inheritParams fitted.lcModel
fitted.lcModelLcmmGMM = function(object, ..., clusters = trajectoryAssignments(object)) {
  predNames = paste0('pred_ss', 1:nClusters(object))

  allVars = unique(c(
    getCovariates(object@method$fixed),
    getCovariates(object@method$mixture),
    getCovariates(object@method$classmb)
  ))

  modelData = model.data(object)
  dataIndex = data.table(
    Id = modelData[[idVariable(object)]],
    Time = modelData[[timeVariable(object)]],
    Include = TRUE
  )
  dataIndex[object@model$na.action, Include := FALSE]

  predMat = object@model$pred[predNames] %>%
    as.matrix() %>%
    set_colnames(clusterNames(object))

  assert_that(
    sum(dataIndex$Include) == nrow(predMat),
    msg = 'modelLcmm implementation error: lcmm model returned object of unexpected number of observations. Please report this issue.'
  )

  dtPred = cbind(dataIndex[Include == TRUE, .(Id, Time)], predMat)

  allPred = dtPred[dataIndex[, .(Id, Time)], on = c('Id', 'Time')]
  allPredMat = subset(allPred, select = clusterNames(object)) %>% as.matrix()

  transformFitted(allPredMat, model = object, clusters = clusters)
}


#. predictForCluster ####
#' @rdname interface-lcmm
#' @inheritParams predictForCluster
setMethod('predictForCluster', 'lcModelLcmmGMM',
  function(
    object,
    newdata,
    cluster,
    what = 'mu',
    ...
  ) {
  assert_that(what == 'mu', msg = 'only what="mu" is supported')
  vars = union(getCovariates(object@model$fixed), getCovariates(object@model$mixture))
  missingVars = setdiff(vars, names(newdata))

  if (nrow(newdata) == 0) {
    return(numeric())
  }

  if (length(missingVars) > 0) {
    # compute marginal means for unspecified covariates
    missingVarMeans = model.data(object) %>%
      subset(select = missingVars) %>%
      vapply(mean, na.rm = TRUE, FUN.VALUE = 0)
    newdata = cbind(newdata, as.data.table(as.list(missingVarMeans))[rep(1L, nrow(newdata))])
    # newdata$Cluster = make.clusterIndices(object, newdata$Cluster)
  }

  predMat = lcmm::predictY(object@model, newdata = newdata)$pred %>%
    set_colnames(clusterNames(object))

  clusIdx = match(cluster, clusterNames(object))

  predMat[, clusIdx]
})


#' @export
#' @rdname interface-lcmm
model.matrix.lcModelLcmmGMM = function(object, ..., what = 'mu') {
  if (what == 'mu') {
    f = merge.formula(object@model$fixed, object@model$mixture)
    model.matrix(f, data = model.data(object))
  } else {
    model.matrix(object@model$mb, data = model.data(object))
  }
}


#' @export
#' @rdname interface-lcmm
logLik.lcModelLcmmGMM = function(object, ...) {
  ll = object@model$loglik
  N = nIds(object)
  df = length(coef(object))
  attr(ll, 'nobs') = N
  attr(ll, 'df') = df
  class(ll) = 'logLik'
  return(ll)
}


#' @export
#' @rdname interface-lcmm
sigma.lcModelLcmmGMM = function(object, ...) {
  coef(object)['stderr'] %>% unname()
}

#' @export
#' @rdname interface-lcmm
nobs.lcModelLcmmGMM = function(object, ...) {
  suppressWarnings({
    data = model.data(object)
  })

  nrow(data) - length(object@model$na.action)
}


#' @rdname interface-lcmm
setMethod('postprob', 'lcModelLcmmGMM', function(object, ...) {
  pp = object@model$pprob %>%
    as.matrix() %>%
    .[, c(-1, -2), drop = FALSE]
  colnames(pp) = clusterNames(object)
  return(pp)
})


#' @rdname interface-lcmm
setMethod('converged', 'lcModelLcmmGMM', function(object, ...) {
  object@model$conv
})