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DisTools: Dissimilarity based pattern recognition
Version 3.0.3 1-Dec-2013

This Matlab toolbox for the analysis of dissimilarity data works only if also the pattern recognition toolbox PRTools version 5 is available. See,

R.P.W. Duin ( E. Pekalksa (

Manipulation of dissimilarity matrices

genddat Generate random training and test sets for dissimilarity data
makesym Make a dissimilarity matrix symmetric
seldclass Select class subset from a square dissimilarity dataset

Characterization of dissimilarity matrices

asymmetry Estimate asymmetry of dissimilarity matrix
nef Compute negative eigen-fraction and negative eigen-ratio
nmf Compute fraction of violations of triangle inequality
issquare Check whether a matrix is square
issym Check whether a matrix is symmetric
intrdim Intrinsic diemensionality
nne Leave-one-out Nearest Neighbor error on a dissimilarity matrix
nnerror1 Exact expected NN error from a dissimilarity matrix
nnerror2 Exact expected NN error from a dissimilarity matrix

Dissimilarity Measures

distm Square Euclidean distance matrix (PRTools)
proxxm Proximity mappings


disnorm Normalization of a dissimilarity matrix (PRTools)
dissimt Fixed DISsimilarity-SIMilarity transformations
makemetric Make a matrix metric
makesym Make a matrix symmetric
pe_em Pseudo-Euclidean embedding (special case: Classical Scaling)
euspace Convert PE space into an Euclidean space

Classification in Pseudo-Euclidean Space and indefinite kernels

dispn Split dissimilarity matrix in positive and negative part
getspectrum Retrieve spectrum form pseudo-Euclidean mapping
setsig Set signature for pseudo-Euclidean dataset or mapping
getsig Retrieve signature of PE mapping or PE dataset
ispe_dataset Test dataset for PE signature setting
ispe_em Test mapping for PE signature setting
nef Compute Negative Eigen Fraction from PE dataset or mapping
nmf Compute Non-Metric Fraction from dissimilarity matrix
pe_distm Square pseudo-Euclidean distance between two datasets
pe_kernelm Compute kernel in PE space
pe_mtimes Matrix multiplication (inner product) in PE space
pe_parzenc Parzen classifier in PE space
pe_knnc KNN classifier in PE space
pe_nmc Nearest mean classifier in PE space
pe_svc Support classifier in PE space
pe_libsvc Support classifier in PE space based on LIBSVM
pe_em Pseudo-Euclidean linear embedding
plotspectrum Plot spectrum of eigenvalues
seleigs Select eigenvalues from a list

Routines supporting learning from dissimilarity matrices

crossvald Cross-validation error for dissimilarity data
clevald Classifier evaluation (learning curve) for dissimilarity data
protselfd Forward prototype selection
dlpc LP-classifier on dissimilarity (proximity) data
knndc K-Nearest Neighbor classifier for dissimilarity matrices
parzenddc Parzen classifier for dissimilarity matrices
testkd Test k-NN classifier for dissimilarity data
testpd Test Parzen classifier for dissimilarity data


disex_spiral The long spiral example
disex_protselfd Example of forward prototype selection
disex_classf DisTools classf example
disex_2dclassf DisTools 2D classf example

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DisTools Guide