vblpcmstart function

Generate sensible starting configuration for the variational parameter set.

Uses fast methods to generate sensible and coherent values for the parameters of the variational method. There are returned as a list and that list may be passed directly to vblpcmfit(). User specification of the configuration is recommended as tweaks to this list only.

vblpcmstart(g.network,G=1,d=2,LSTEPS=5e3,model="plain", CLUST=0, B=NULL,
           lcc=TRUE, edgecovs=NULL,sendcovs=NULL,receivecovs=NULL,
           socialcovs=NULL,START="FR", seed=NaN)

Arguments

• g.network: a network object
• G: Desired number of groups
• d: Desired dimensionality of the latent space
• LSTEPS: Number of steps in the log-likelihood forces algorithm
• model: model specified as "plain", "rreceiver", "rsender" or "rsocial". See vblpcmcovs for details.
• CLUST: degree of push to clustering at the start
• B: default intercept value
• lcc: logical indicator. TRUE => analyze largest connected component of g.network only FALSE => analyze the whole network.
• edgecovs: optional edge covariates.
• sendcovs: optional sender node covariates.
• receivecovs: optional receiver node covariates.
• socialcovs: optional sociality node covariates.
• START: what to start the initial positions with. "FR" for Fruchterman-Reingold. "geodesic" for geodesic distances. "laplace" for using the Graph Laplacian. "random" for random.
• seed: Optional seed for the random number generator in R. Equivalent to using set.seed(seed). The default NaN value does not call set.seed().

Returns

A v.params list containing the latent positions, clustering membership probabilities, etc.

Author(s)

Michael Salter-Townshend

See Also

vblpcmfit, vblpcmcovs

Examples

data(sampson)
### plot the mean posterior positions with initial estimations for variational parameters
plot(vblpcmstart(samplike,G=3),main="Sampson's Monks: VB Initial Values")
### plot the mean posterior positions with final estimations for variational parameters
plot(vblpcmfit(vblpcmstart(samplike,G=3)),main="Sampson's Monks: VB Solution")