- # (normalized) observations node with CWT
- Xcwt4 <- lapply(seq_len(n), function(i) {
- ts <- scale(ts(curves[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 / max(Mod(sqres))
- })
-
- Xwer_dist <- matrix(0., n, n)
- fcoefs = rep(1/3, 3) #moving average on 3 values (TODO: very slow! correct?!)
- for (i in 1:(n-1))
+ Xwer_dist <- bigmemory::big.matrix(nrow=n, ncol=n, type="double")
+ fcoefs = rep(1/3, 3) #moving average on 3 values
+
+ # Generate n(n-1)/2 pairs for WER distances computations
+ pairs = list()
+ V = seq_len(n)
+ for (i in 1:n)
+ {
+ V = V[-1]
+ pairs = c(pairs, lapply(V, function(v) c(i,v)))
+ }
+
+ # Distance between rows i and j
+ computeDistancesIJ = function(pair)
+ {
+ require("bigmemory", quietly=TRUE)
+ require("epclust", quietly=TRUE)
+ synchrones <- bigmemory::attach.big.matrix(synchrones_desc)
+ Xwer_dist <- bigmemory::attach.big.matrix(Xwer_dist_desc)
+
+ computeCWT = function(i)
+ {
+ ts <- scale(ts(synchrones[i,]), center=TRUE, scale=scaled)
+ totts.cwt = Rwave::cwt(ts, totnoct, nvoice, w0, plot=FALSE)
+ ts.cwt = totts.cwt[,s0log:(s0log+noctave*nvoice)]
+ #Normalization
+ sqs <- sqrt(2^(0:(noctave*nvoice)/nvoice)*s0)
+ sqres <- sweep(ts.cwt,2,sqs,'*')
+ sqres / max(Mod(sqres))
+ }
+
+ i = pair[1] ; j = pair[2]
+ if (verbose && j==i+1)
+ cat(paste(" Distances (",i,",",j,"), (",i,",",j+1,") ...\n", sep=""))
+ cwt_i = computeCWT(i)
+ cwt_j = computeCWT(j)
+ num <- epclustFilter(Mod(cwt_i * Conj(cwt_j)))
+ WX <- epclustFilter(Mod(cwt_i * Conj(cwt_i)))
+ WY <- epclustFilter(Mod(cwt_j * Conj(cwt_j)))
+ wer2 <- sum(colSums(num)^2) / sum(colSums(WX) * colSums(WY))
+ Xwer_dist[i,j] <- sqrt(delta * ncol(cwt_i) * (1 - wer2))
+ Xwer_dist[j,i] <- Xwer_dist[i,j]
+ Xwer_dist[i,i] = 0.
+ }
+
+ if (parll)
+ {
+ cl = parallel::makeCluster(ncores_clust)
+ synchrones_desc <- bigmemory::describe(synchrones)
+ Xwer_dist_desc_desc <- bigmemory::describe(Xwer_dist)
+
+ parallel::clusterExport(cl, varlist=c("synchrones_desc","Xwer_dist_desc","totnoct",
+ "nvoice","w0","s0log","noctave","s0","verbose"), envir=environment())
+ }
+
+ ignored <-
+ if (parll)
+ parallel::parLapply(cl, pairs, computeDistancesIJ)
+ else
+ lapply(pairs, computeDistancesIJ)
+
+ if (parll)
+ parallel::stopCluster(cl)
+
+ Xwer_dist[n,n] = 0.
+ distances <- Xwer_dist[,]
+ rm(Xwer_dist) ; gc()
+ distances #~small matrix K1 x K1
+}
+
+# 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