R/getJointModel.R

In bogdanoancea/deduplication: R package for computing the duplicity probility for each mobile device.

#' @title Builds the joint HMM model.
#'
#' @description Builds the joint HMM model using the emmission probabilities 
#' given by \code{getEmissionProbsJointModel()}.
#'
#' @param nrows Number of rows in the grid.
#'
#' @param ncols Number of columns in the grid.
#'
#' @param jointEmissionProbs A (sparse) matrix with the joint event location 
#' probabilities. The number of rows equals the number of tiles in the grid and 
#' the number of columns equals the number of antennas. This matrix is obtained by
#' calling \code{getEmissionProbsJointModel}.
#'
#' @param initSteady If TRUE the initial apriori distribution is set to the 
#' steady state of the transition matrix, if FALSE the apriori distribution 
#' should be given as a parameter.
#'
#' @param aprioriJointProb The apriori distribution for the HMM model. It is 
#' needed only if initSteady is FALSE.
#'
#' @return Returns an HMM model with the initial apriori distribution set to the 
#' steady state of the transition matrix or to the value given by 
#' \code{aprioriJointProb} parameter.
#'
#' @import destim
#' @export
getJointModel <-
  function(nrows,ncols,jointEmissionProbs, initSteady = TRUE, aprioriJointProb = NULL) {
   
    modeljoin <- HMMrectangle(nrows, ncols)
    emissions(modeljoin) <- jointEmissionProbs
    modeljoin <- initparams(modeljoin)
    modeljoin <- minparams(modeljoin)
    
    
    if ( initSteady && !is.null(aprioriJointProb)) {
      stop("getJointModel: either initSteady is TRUE and aprioriJointProb is NULL or initSteady is FALSE and aprioriJointProb is 
         not NULL")
    }
    
    if ( !initSteady && is.null(aprioriJointProb)) {
      stop("getJointModel: either initSteady is TRUE and aprioriJointProb is NULL or initSteady is FALSE and aprioriProb is 
         not NULL")
    }
    
    
    if (initSteady == TRUE) {
      modeljoin <- initsteady(modeljoin)
    } else {
      if(is.null(aprioriJointProb) ) {
        stop("getJointModel: if initSteady is FALSE then you should specify the apriori probability for the HMM model!")
      }
      else {
        if(abs(sum(aprioriJointProb) - 1) > .Machine$double.eps)
          stop("getJointModel: aprioriJointProb should sum up to 1!")
        else
          istates(modeljoin)<-aprioriJointProb
      }
    }
    
    return(modeljoin)
  }