X-Git-Url: https://git.auder.net/?p=valse.git;a=blobdiff_plain;f=pkg%2FR%2FEMGrank.R;h=b85a0faf4fd9b1b2cea2c4f7b11ccf5c9371a08d;hp=0e68cb4ecdf4dd9f9270557823d76a3875a7f72e;hb=e32621012b1660204434a56acc8cf73eac42f477;hpb=a3105972158da4773b33d41e1ead65a942c15f80 diff --git a/pkg/R/EMGrank.R b/pkg/R/EMGrank.R deleted file mode 100644 index 0e68cb4..0000000 --- a/pkg/R/EMGrank.R +++ /dev/null @@ -1,124 +0,0 @@ -#' EMGrank -#' -#' Description de EMGrank -#' -#' @param phiInit ... -#' @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 = dim(X)[1] - p = dim(X)[2] - m = dim(Rho)[2] - k = dim(Rho)[3] - - #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: Mise à jour de Beta (et donc phi) - for(r in 1:k) - { - Z_indice = seq_len(n)[Z==r] #indices où Z == r - if (length(Z_indice) == 0) - next - #U,S,V = SVD of (t(Xr)Xr)^{-1} * t(Xr) * Yr - s = svd( 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] - } - - #Etape E et calcul de LLF - 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(det(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)) -}