-# Cluster one full task (nb_curves / ntasks series); only step 1
-clusteringTask = function(indices, getCoefs, K1, nb_series_per_chunk, ncores)
+#' @name clustering
+#' @rdname clustering
+#' @aliases clusteringTask1 computeClusters1 computeClusters2
+#'
+#' @title Two-stage clustering, withing one task (see \code{claws()})
+#'
+#' @description \code{clusteringTask1()} runs one full stage-1 task, which consists in
+#' iterated stage 1 clustering (on nb_curves / ntasks energy contributions, computed
+#' through discrete wavelets coefficients). \code{computeClusters1()} and
+#' \code{computeClusters2()} correspond to the atomic clustering procedures respectively
+#' for stage 1 and 2. The former applies the clustering algorithm (PAM) on a
+#' contributions matrix, while the latter clusters a chunk of series inside one task
+#' (~max nb_series_per_chunk)
+#'
+#' @param indices Range of series indices to cluster in parallel (initial data)
+#' @param getContribs Function to retrieve contributions from initial series indices:
+#' \code{getContribs(indices)} outpus a contributions matrix
+#' @param contribs matrix of contributions (e.g. output of \code{curvesToContribs()})
+#' @inheritParams computeSynchrones
+#' @inheritParams claws
+#'
+#' @return For \code{clusteringTask1()} and \code{computeClusters1()}, the indices of the
+#' computed (K1) medoids. Indices are irrelevant for stage 2 clustering, thus
+#' \code{computeClusters2()} outputs a matrix of medoids
+#' (of size limited by nb_series_per_chunk)
+NULL
+
+#' @rdname clustering
+#' @export
+clusteringTask1 = function(
+ indices, getContribs, K1, nb_series_per_chunk, ncores_clust=1, verbose=FALSE, parll=TRUE)
{
- cl = parallel::makeCluster(ncores)
- repeat
+ if (verbose)
+ cat(paste("*** Clustering task on ",length(indices)," lines\n", sep=""))
+
+ wrapComputeClusters1 = function(inds) {
+ if (parll)
+ require("epclust", quietly=TRUE)
+ if (verbose)
+ cat(paste(" computeClusters1() on ",length(inds)," lines\n", sep=""))
+ inds[ computeClusters1(getContribs(inds), K1) ]
+ }
+
+ if (parll)
+ {
+ cl = parallel::makeCluster(ncores_clust)
+ parallel::clusterExport(cl, varlist=c("getContribs","K1","verbose"), envir=environment())
+ }
+ while (length(indices) > K1)
{
- nb_workers = max( 1, round( length(indices) / nb_series_per_chunk ) )
- indices_workers = lapply(seq_len(nb_workers), function(i) {
- upper_bound = ifelse( i<nb_workers,
- min(nb_series_per_chunk*i,length(indices)), length(indices) )
- indices[(nb_series_per_chunk*(i-1)+1):upper_bound]
- })
- indices = unlist( parallel::parLapply(cl, indices_workers, function(inds)
- computeClusters1(getCoefs(inds), K1)) )
- if (length(indices) == K1)
- break
+ indices_workers = .spreadIndices(indices, nb_series_per_chunk)
+ if (parll)
+ indices = unlist( parallel::parLapply(cl, indices_workers, wrapComputeClusters1) )
+ else
+ indices = unlist( lapply(indices_workers, wrapComputeClusters1) )
}
- parallel::stopCluster(cl)
+ if (parll)
+ parallel::stopCluster(cl)
+
indices #medoids
}
-# Apply the clustering algorithm (PAM) on a coeffs or distances matrix
-computeClusters1 = function(coefs, K1)
- indices[ cluster::pam(coefs, K1, diss=FALSE)$id.med ]
+#' @rdname clustering
+#' @export
+computeClusters1 = function(contribs, K1)
+ cluster::pam(contribs, K1, diss=FALSE)$id.med
-# Cluster a chunk of series inside one task (~max nb_series_per_chunk)
-computeClusters2 = function(medoids, K2, getRefSeries, nb_series_per_chunk)
+#' @rdname clustering
+#' @export
+computeClusters2 = function(medoids, K2,
+ getRefSeries, nb_ref_curves, nb_series_per_chunk, ncores_clust=1,verbose=FALSE,parll=TRUE)
{
- synchrones = computeSynchrones(medoids, getRefSeries, nb_series_per_chunk)
- cluster::pam(computeWerDists(synchrones), K2, diss=TRUE)$medoids
+ synchrones = computeSynchrones(medoids,
+ getRefSeries, nb_ref_curves, nb_series_per_chunk, ncores_clust, verbose, parll)
+ distances = computeWerDists(synchrones, ncores_clust, verbose, parll)
+ medoids[ cluster::pam(distances, K2, diss=TRUE)$medoids , ]
}
-# Compute the synchrones curves (sum of clusters elements) from a clustering result
-computeSynchrones = function(medoids, getRefSeries, nb_series_per_chunk)
+#' computeSynchrones
+#'
+#' Compute the synchrones curves (sum of clusters elements) from a matrix of medoids,
+#' using L2 distances.
+#'
+#' @param medoids Matrix of medoids (curves of same legnth as initial series)
+#' @param getRefSeries Function to retrieve initial series (e.g. in stage 2 after series
+#' have been replaced by stage-1 medoids)
+#' @param nb_ref_curves How many reference series? (This number is known at this stage)
+#' @inheritParams claws
+#'
+#' @export
+computeSynchrones = function(medoids, getRefSeries,
+ nb_ref_curves, nb_series_per_chunk, ncores_clust=1,verbose=FALSE,parll=TRUE)
{
- #les getSeries(indices) sont les medoides --> init vect nul pour chacun, puis incr avec les
- #courbes (getSeriesForSynchrones) les plus proches... --> au sens de la norme L2 ?
- K = nrow(medoids)
- synchrones = matrix(0, nrow=K, ncol=ncol(medoids))
- counts = rep(0,K)
- index = 1
- repeat
+ computeSynchronesChunk = function(indices)
{
- range = (index-1) + seq_len(nb_series_per_chunk)
- ref_series = getRefSeries(range)
- if (is.null(ref_series))
- break
+ ref_series = getRefSeries(indices)
#get medoids indices for this chunk of series
for (i in seq_len(nrow(ref_series)))
{
- j = which.min( rowSums( sweep(medoids, 2, series[i,], '-')^2 ) )
- synchrones[j,] = synchrones[j,] + series[i,]
- counts[j] = counts[j] + 1
+ j = which.min( rowSums( sweep(medoids, 2, ref_series[i,], '-')^2 ) )
+ if (parll)
+ synchronicity::lock(m)
+ synchrones[j,] = synchrones[j,] + ref_series[i,]
+ counts[j,1] = counts[j,1] + 1
+ if (parll)
+ synchronicity::unlock(m)
}
- index = index + nb_series_per_chunk
+ }
+
+ K = nrow(medoids)
+ # Use bigmemory (shared==TRUE by default) + synchronicity to fill synchrones in //
+ synchrones = bigmemory::big.matrix(nrow=K,ncol=ncol(medoids),type="double",init=0.)
+ counts = bigmemory::big.matrix(nrow=K,ncol=1,type="double",init=0)
+ # Fork (// run) only on Linux & MacOS; on Windows: run sequentially
+ parll = (requireNamespace("synchronicity",quietly=TRUE)
+ && parll && Sys.info()['sysname'] != "Windows")
+ if (parll)
+ m <- synchronicity::boost.mutex()
+
+ indices_workers = .spreadIndices(seq_len(nb_ref_curves), nb_series_per_chunk)
+ for (inds in indices_workers)
+ {
+ if (verbose)
+ cat(paste("--- Compute synchrones for ",length(inds)," lines\n", sep=""))
+ if (parll)
+ ignored <- parallel::mcparallel(computeSynchronesChunk(inds))
+ else
+ computeSynchronesChunk(inds)
+ }
+ if (parll)
+ parallel::mccollect()
+
+ mat_syncs = matrix(nrow=K, ncol=ncol(medoids))
+ vec_count = rep(NA, K)
+ #TODO: can we avoid this loop?
+ for (i in seq_len(K))
+ {
+ mat_syncs[i,] = synchrones[i,]
+ vec_count[i] = counts[i,1]
}
#NOTE: odds for some clusters to be empty? (when series already come from stage 2)
- sweep(synchrones, 1, counts, '/')
+ # ...maybe; but let's hope resulting K1' be still quite bigger than K2
+ mat_syncs = sweep(mat_syncs, 1, vec_count, '/')
+ mat_syncs[ sapply(seq_len(K), function(i) all(!is.nan(mat_syncs[i,]))) , ]
}
-# Compute the WER distance between the synchrones curves (in rows)
-computeWerDist = function(curves)
+#' computeWerDists
+#'
+#' Compute the WER distances between the synchrones curves (in rows), which are
+#' returned (e.g.) by \code{computeSynchrones()}
+#'
+#' @param synchrones A matrix of synchrones, in rows. The series have same length as the
+#' series in the initial dataset
+#' @inheritParams claws
+#'
+#' @export
+computeWerDists = function(synchrones, ncores_clust=1,verbose=FALSE,parll=TRUE)
{
- if (!require("Rwave", quietly=TRUE))
- stop("Unable to load Rwave library")
- n <- nrow(curves)
- delta <- ncol(curves)
+ n <- nrow(synchrones)
+ delta <- ncol(synchrones)
#TODO: automatic tune of all these parameters ? (for other users)
nvoice <- 4
- # noctave = 2^13 = 8192 half hours ~ 180 days ; ~log2(ncol(curves))
+ # noctave = 2^13 = 8192 half hours ~ 180 days ; ~log2(ncol(synchrones))
noctave = 13
# 4 here represent 2^5 = 32 half-hours ~ 1 day
#NOTE: default scalevector == 2^(0:(noctave * nvoice) / nvoice) * s0 (?)
s0log = as.integer( (log2( s0*w0/(2*pi) ) - 1) * nvoice + 1.5 )
totnoct = noctave + as.integer(s0log/nvoice) + 1
- # (normalized) observations node with CWT
- Xcwt4 <- lapply(seq_len(n), function(i) {
- ts <- scale(ts(curves[i,]), center=TRUE, scale=scaled)
+ computeCWT = function(i)
+ {
+ if (verbose)
+ cat(paste("+++ Compute Rwave::cwt() on serie ",i,"\n", sep=""))
+ ts <- scale(ts(synchrones[i,]), center=TRUE, scale=scaled)
totts.cwt = Rwave::cwt(ts,totnoct,nvoice,w0,plot=0)
ts.cwt = totts.cwt[,s0log:(s0log+noctave*nvoice)]
#Normalization
sqs <- sqrt(2^(0:(noctave*nvoice)/nvoice)*s0)
- sqres <- sweep(ts.cwt,MARGIN=2,sqs,'*')
+ sqres <- sweep(ts.cwt,2,sqs,'*')
sqres / max(Mod(sqres))
- })
+ }
+
+ if (parll)
+ {
+ cl = parallel::makeCluster(ncores_clust)
+ parallel::clusterExport(cl,
+ varlist=c("synchrones","totnoct","nvoice","w0","s0log","noctave","s0","verbose"),
+ envir=environment())
+ }
- Xwer_dist <- matrix(0., n, n)
+ # (normalized) observations node with CWT
+ Xcwt4 <-
+ if (parll)
+ parallel::parLapply(cl, seq_len(n), computeCWT)
+ else
+ lapply(seq_len(n), computeCWT)
+
+ if (parll)
+ parallel::stopCluster(cl)
+
+ Xwer_dist <- bigmemory::big.matrix(nrow=n, ncol=n, type="double")
fcoefs = rep(1/3, 3) #moving average on 3 values (TODO: very slow! correct?!)
- for (i in 1:(n-1))
+ if (verbose)
+ cat("*** Compute WER distances from CWT\n")
+
+ computeDistancesLineI = function(i)
{
+ if (verbose)
+ cat(paste(" Line ",i,"\n", sep=""))
for (j in (i+1):n)
{
- #TODO: later, compute CWT here (because not enough storage space for 200k series)
- # 'circular=TRUE' is wrong, should just take values on the sides; to rewrite in C
+ #TODO: 'circular=TRUE' is wrong, should just take values on the sides; to rewrite in C
num <- filter(Mod(Xcwt4[[i]] * Conj(Xcwt4[[j]])), fcoefs, circular=TRUE)
WX <- filter(Mod(Xcwt4[[i]] * Conj(Xcwt4[[i]])), fcoefs, circular=TRUE)
WY <- filter(Mod(Xcwt4[[j]] * Conj(Xcwt4[[j]])), fcoefs, circular=TRUE)
wer2 <- sum(colSums(num)^2) / sum( sum(colSums(WX) * colSums(WY)) )
+ if (parll)
+ synchronicity::lock(m)
Xwer_dist[i,j] <- sqrt(delta * ncol(Xcwt4[[1]]) * (1 - wer2))
Xwer_dist[j,i] <- Xwer_dist[i,j]
+ if (parll)
+ synchronicity::unlock(m)
+ }
+ Xwer_dist[i,i] = 0.
+ }
+
+ parll = (requireNamespace("synchronicity",quietly=TRUE)
+ && parll && Sys.info()['sysname'] != "Windows")
+ if (parll)
+ m <- synchronicity::boost.mutex()
+
+ for (i in 1:(n-1))
+ {
+ if (parll)
+ ignored <- parallel::mcparallel(computeDistancesLineI(i))
+ else
+ computeDistancesLineI(i)
+ }
+ Xwer_dist[n,n] = 0.
+
+ if (parll)
+ parallel::mccollect()
+
+ mat_dists = matrix(nrow=n, ncol=n)
+ #TODO: avoid this loop?
+ for (i in 1:n)
+ mat_dists[i,] = Xwer_dist[i,]
+ mat_dists
+}
+
+# Helper function to divide indices into balanced sets
+.spreadIndices = function(indices, nb_per_chunk)
+{
+ L = length(indices)
+ nb_workers = floor( L / nb_per_chunk )
+ if (nb_workers == 0)
+ {
+ # L < nb_series_per_chunk, simple case
+ indices_workers = list(indices)
+ }
+ else
+ {
+ indices_workers = lapply( seq_len(nb_workers), function(i)
+ indices[(nb_per_chunk*(i-1)+1):(nb_per_chunk*i)] )
+ # Spread the remaining load among the workers
+ rem = L %% nb_per_chunk
+ while (rem > 0)
+ {
+ index = rem%%nb_workers + 1
+ indices_workers[[index]] = c(indices_workers[[index]], indices[L-rem+1])
+ rem = rem - 1
}
}
- diag(Xwer_dist) <- numeric(n)
- Xwer_dist
+ indices_workers
}