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graphseg (version 0.1.1)

flsa_graph: Segmentation using graph structure and the fused lasso estimate

Description

Wrapper around the function flsa::flsa, which computes the fused lasso signal approximator (see reference). Like agraph, this function takes a signal on graph and returns a clustering thereof into a piecewise-constant signal. The difference with agraph is the estimation method: agraph works well when the true signal is sparse and its computation time scales well to large graphs.

Usage

flsa_graph(gamma, graph, lambda)

Value

A list with the following elements:

  • result: matrix whose rows are the segmented output of input signal gamma, for each value of lambda

  • bic, gcv, and aic: vectors of length length(lambda), giving the BIC, GCV, and AIC criteria for each value of lambda. See references below.

  • model_dim, nll: vectors of length length(lambda), giving the model dimension and negative log-likelihood for each value of lambda. See reference below for the definition of these terms.

Arguments

gamma

entry vector to regularize

graph

graph (an igraph object) giving the regularization structure

lambda

regularizing constant

References

Hoefling, H., A Path Algorithm for the Fused Lasso Signal Approximator, Journal of Computational and Graphical Statistics (2010) tools:::Rd_expr_doi("10.1198/jcgs.2010.09208")

See Also

graphseg::agraph()