X-Git-Url: https://git.auder.net/?p=valse.git;a=blobdiff_plain;f=pkg%2FR%2FEMGrank.R;fp=pkg%2FR%2FEMGrank.R;h=0000000000000000000000000000000000000000;hp=b85a0faf4fd9b1b2cea2c4f7b11ccf5c9371a08d;hb=e32621012b1660204434a56acc8cf73eac42f477;hpb=ea5860f1b4fc91f06e371a0b26915198474a849d diff --git a/pkg/R/EMGrank.R b/pkg/R/EMGrank.R deleted file mode 100644 index b85a0fa..0000000 --- a/pkg/R/EMGrank.R +++ /dev/null @@ -1,120 +0,0 @@ -#' EMGrank -#' -#' Description de EMGrank -#' -#' @param Pi Parametre de proportion -#' @param Rho Parametre initial de variance renormalisé -#' @param mini Nombre minimal d'itérations dans l'algorithme EM -#' @param maxi Nombre maximal d'itérations dans l'algorithme EM -#' @param X Régresseurs -#' @param Y Réponse -#' @param tau Seuil pour accepter la convergence -#' @param rank Vecteur des rangs possibles -#' -#' @return A list ... -#' phi : parametre de moyenne renormalisé, calculé par l'EM -#' LLF : log vraisemblance associé à cet échantillon, pour les valeurs estimées des paramètres -#' -#' @export -EMGrank <- function(Pi, Rho, mini, maxi, X, Y, tau, rank, fast = TRUE) -{ - if (!fast) - { - # Function in R - return(.EMGrank_R(Pi, Rho, mini, maxi, X, Y, tau, rank)) - } - - # Function in C - n <- nrow(X) #nombre d'echantillons - p <- ncol(X) #nombre de covariables - m <- ncol(Y) #taille de Y (multivarié) - k <- length(Pi) #nombre de composantes dans le mélange - .Call("EMGrank", Pi, Rho, mini, maxi, X, Y, tau, rank, phi = double(p * m * k), - LLF = double(1), n, p, m, k, PACKAGE = "valse") -} - -# helper to always have matrices as arg (TODO: put this elsewhere? improve?) --> -# Yes, we should use by-columns storage everywhere... [later!] -matricize <- function(X) -{ - if (!is.matrix(X)) - return(t(as.matrix(X))) - return(X) -} - -# R version - slow but easy to read -.EMGrank_R <- function(Pi, Rho, mini, maxi, X, Y, tau, rank) -{ - # matrix dimensions - n <- nrow(X) - p <- ncol(X) - m <- ncol(Y) - k <- length(Pi) - - # init outputs - phi <- array(0, dim = c(p, m, k)) - Z <- rep(1, n) - LLF <- 0 - - # local variables - Phi <- array(0, dim = c(p, m, k)) - deltaPhi <- c() - sumDeltaPhi <- 0 - deltaPhiBufferSize <- 20 - - # main loop - ite <- 1 - while (ite <= mini || (ite <= maxi && sumDeltaPhi > tau)) - { - # M step: update for Beta ( and then phi) - for (r in 1:k) - { - Z_indice <- seq_len(n)[Z == r] #indices where Z == r - if (length(Z_indice) == 0) - next - # U,S,V = SVD of (t(Xr)Xr)^{-1} * t(Xr) * Yr - s <- svd(MASS::ginv(crossprod(matricize(X[Z_indice, ]))) %*% - crossprod(matricize(X[Z_indice, ]), matricize(Y[Z_indice, ]))) - S <- s$d - # Set m-rank(r) singular values to zero, and recompose best rank(r) approximation - # of the initial product - if (rank[r] < length(S)) - S[(rank[r] + 1):length(S)] <- 0 - phi[, , r] <- s$u %*% diag(S) %*% t(s$v) %*% Rho[, , r] - } - - # Step E and computation of the loglikelihood - sumLogLLF2 <- 0 - for (i in seq_len(n)) - { - sumLLF1 <- 0 - maxLogGamIR <- -Inf - for (r in seq_len(k)) - { - dotProduct <- tcrossprod(Y[i, ] %*% Rho[, , r] - X[i, ] %*% phi[, , r]) - logGamIR <- log(Pi[r]) + log(gdet(Rho[, , r])) - 0.5 * dotProduct - # Z[i] = index of max (gam[i,]) - if (logGamIR > maxLogGamIR) - { - Z[i] <- r - maxLogGamIR <- logGamIR - } - sumLLF1 <- sumLLF1 + exp(logGamIR)/(2 * pi)^(m/2) - } - sumLogLLF2 <- sumLogLLF2 + log(sumLLF1) - } - - LLF <- -1/n * sumLogLLF2 - - # update distance parameter to check algorithm convergence (delta(phi, Phi)) - deltaPhi <- c(deltaPhi, max((abs(phi - Phi))/(1 + abs(phi)))) #TODO: explain? - if (length(deltaPhi) > deltaPhiBufferSize) - deltaPhi <- deltaPhi[2:length(deltaPhi)] - sumDeltaPhi <- sum(abs(deltaPhi)) - - # update other local variables - Phi <- phi - ite <- ite + 1 - } - return(list(phi = phi, LLF = LLF)) -}