DD_tools: dissim

DISSIM Dissimilarity transformations

    W = DISSIM([],TTYPE,PAR)

 Define a mapping for a 1-to-1 transformation.
 Possible transformations TTYPE are:
 
      TTYPE
  'identity','i'  out = in;
  'd2s','s2d'     out = 1-in;                     D->S->D
  'diag','g'      out_ij = in_ii+in_jj-2in_ij        S->D
  'sqrt','q'      out = sqrt(1-in)                   D->S
  'rbf','r'       out = exp(-in*in/(par(1)*par(1)))  D->S
  'exp','e'       out = exp(-in/par(1))              D->S
  'mlog','m'      out = -log(in/par(1))
  'sigm','s'      out = 2/(1+exp(-in/par(1))) - 1    D->D
  'dsigm','d'     out = 4par(1)/(1+exp(-in/par(1))) - 2par(1)    D->D
                  ('d' is similar to 's', only a scaled version)

    W = DISSIM(A,TTYPE,PAR)

 If a dataset A is supplied, the data is directly mapped (and thus
 no mapping is defined).

 Note: I agree that the name is not very fortunate, but I didn't
 have enough inspiration for a good one:-)

See also: myproxm |proxm| sqeucldistm 



Copyright: D.M.J. Tax, D.M.J.Tax@prtools.org
Faculty EWI, Delft University of Technology
P.O. Box 5031, 2600 GA Delft, The Netherlands