ncuth
PURPOSE
Minimum Normalised Cut Hyperplane
SYNOPSIS
function [idx,sol] = ncuth(X, varargin)
DESCRIPTION
Minimum Normalised Cut Hyperplane [IDX,SOL] = NCUTH(DATA, VARARGIN) [IDX,SOL] = NCUTH(X) bi-partitions the points in the N-by-D data matrix X with the hyperplane that minimises the normalised cut criterion (computed on one-dimensional projections of the data). NCUTH returns a vector IDX containing the binary cluster assignment and a minimum Normalised Cut Hyperplane (nchp) object SOL. (If S initial projection vectors are specified S nchp hyperplanes are returned: see v0 option) [IDX,SOL] = NCUTH(X, 'PARAM1',val1, 'PARAM2',val2, ...) specifies optional parameters in the form of name/value pairs. OPTIONAL PARAMETERS: 'v0' - D-by-S matrix of S initial projection vectors. (default: v0 = pca(X,'NumComponents',1) : First principal component of X) 'sigma' - positive numeric scaling parameter (sigma) (default: sigma = 100*\sqrt(\lambda_1)*N^(-0.2), where \lambda_1 is the 1st eigenvalue of cov(X)) 'minsize' - Minimum cluster size (integer) (default minsize = 1) 'maxit' - Number of BFGS iterations to perform for each value of alpha (default: 50) 'ftol' - Stopping criterion for change in objective function value over consecutive iterations (default: 1.e-7) 'verb' - Verbosity. Values greater than 0 enable visualisation during execution (default: 0) 'labels' - true cluster assignment. Enables the computation of performance over successive iterations and a better visualisation of how clusters are split 'colours' - Matrix containing colour specification for observations in different clusters Number of rows must be equal to the number of true clusters (if 'labels' has been specified) or equal to 2. Reference: D.P. Hofmeyr. Clustering by Minimum Cut Hyperplanes. IEEE Transactions on Pattern Analysis and Machine Intelligence, 39(8):1547-1560, 2017.
CROSS-REFERENCE INFORMATION
This function calls:- ifelse Shorthand for ternary operator: if-then-else
- myparser Function used to parse optional arguments in form of Name,Value pairs for a number of OPC algorithms
- pcacomp Returns the principal components of (X) specified in vector (index)
- ncut_sigma Default scaling parameter employed by Gaussian kernel in minimum normalised cut projection pursuit
- ncutpp Minimum normalised cut projection pursuit
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