R/posterior.R

In dawai: Discriminant Analysis with Additional Information

posterior <-
function(y, means, variances, prior, numgroups, dimension)
{
    values <- array(NA, c(dim(y)[1], numgroups))
    if(dimension == 1)
        for(i in 1:numgroups)
            values[, i] <- dnorm(y, mean = means[i], sd = sqrt(variances[, , i]), log = TRUE)
    else
        for(i in 1:numgroups)
            values[, i] <- c(apply(y, 1, dmvnorm, mean = means[{dimension*{i - 1} + 1}:{dimension*i}], 
                                   sigma = variances[, , i], log = TRUE))
    values <- t(t(exp(values - apply(values, 1, max)))*c(prior))
    values <- values / rowSums(values)
    return(values)
}