clusterpath.l1.general: clusterpath l1 general

In clusterpath: Fast agglomerative convex clustering, non-Rcpp implementation

Description

Use the l2 descent problem with general weights to solve the weighted l1 problem, separately for each dimension. If the parallel package is installed each dimension will be processed on a separate core. This is useful since the path algorithm can't be used for general weights, since it only is proven to find the optimal solutions for the identity weights.

Usage

clusterpath.l1.general(x, join.thresh = NULL, verbose = 0, gamma = 0, 
    ...)

Arguments

x	Data matrix to cluster.
join.thresh	Threshold for fusion. If NULL take a small fraction of the nonzero differences found in the original points x. Passed to clusterpath.l2.general.
verbose	Passed to clusterpath.l2.general.
gamma	Used for calculating weights using \exp(-γ ||x_i-x_j||^2).
...	passed to clusterpath.l2.general.

Value

Data frame of optimal solutions, with 1 row for each α_i for each lambda.

Author(s)

Toby Dylan Hocking

References

Hocking, Joulin, Bach, Vert ICML 2011.

Examples

set.seed(7)
library(clusterpath)
sim <- gendata(D=2)
## compare with path algorithm
path <- clusterpath.l1.id(sim$mat)
bpts <- castbreakpoints(path)
p <- plot2d(bpts)
descent.pts <- clusterpath.l1.general(sim$mat)
p+geom_point(aes(alpha.1,alpha.2,size=lambda/max(lambda)),data=descent.pts)
desc <- melt(descent.pts[,1:4],measure=c("alpha.1","alpha.2"))
if(require(latticeExtra)){
  plot(path)+
    xyplot(value~lambda|variable,desc,groups=row)
}
library(ggplot2)
## compare with cvx
if(cvxmod.available()){
  gamma <- 0.1
  descent.weights <- clusterpath.l1.general(sim$mat,gamma=gamma,lambda=0.001)
  lvals <- c(seq(min(descent.weights$lambda),0.02,l=4),
             seq(0.02,max(descent.weights$lambda),l=4))
  cvx <- cvxmod.cluster(sim$mat,lvals,norm=1,gamma=gamma)
  both <- rbind(descent.weights,cvx)
  molt <- melt(both,measure=c("alpha.1","alpha.2"))
  ggplot(molt,aes(log(lambda+1),value,colour=solver))+
    geom_point(aes(shape=solver))+
    facet_grid(variable~.,scales="free")
}

clusterpath documentation built on June 30, 2020, 3:02 a.m.