SDPROX  Proximity representation

 Direct computation of proximities to prototypes
   D=sdprox(DATA,PROTO)
   D=sdprox(DATA,PROTO,TYPE,PAR)

 Creating proximity pipeline for computing proximities later
   PP=SDPROX(PROTO,TYPE,PAR)

 INPUT
  DATA     SDDATA set or data matrix with samples to be used
           for direct proximity computation
  PROTO    SDDATA or data matrix with prototype samples
  TYPE     proximity type
   SQEUCL    squared Euclidean distance (default)
   EUCL      Euclidean distance
   POLY      polynomial kernel (PAR degree, def=3)
   RBF       radial basis kernel (PAR sigma, def=1.0)
   SAM       Spectral Angle Mapper
   ASAM      ACOS of Spectral Angle Mapper
   KOL       Kolmogorov distance (assummes that feature vectors
             sum-to-one, use SDNORM)
   MATCH     Matching distance (sum of differences between
             cum.distr.func, assumes features sum-to-one)
  PAR      proximity parameter (optional)

 OUTPUT
  PP       pipeline object

 DESCRIPTION
 SDPROX computes proximities to a set of prototypes. If DATA and PROTO are
 provided, SDPROX returns SDDATA object with proximity values.  If only
 PROTO is given, SDPROX returns the pipline PP which may be applied to any
 new DATA to compute proximities.

 EXAMPLES
 >> D=sdprox(data,proto)  % compute squared Euclidean distances
 >> D=sdprox(data,proto,'SAM')  % compute Spectral Angle Mapper distances
 >> pp=sdprox(proto,'eucl'); D=data*pp % create and apply proximity pipeline