prtKernelHyperbolicTangent  Hyperbolic tangent kernel
 
   kernelObj = prtKernelHyperbolicTangent; Generates a kernel object
   implementing a hyperbolic tangent.  Kernel objects are widely used
   in several prt classifiers, such as prtClassRvm and prtClassSvm.
   Hyperbolic tangent kernels implement the following function for 1 x
   N vectors x1 and x2:
 
    k(x1,x2) = tanh(kappa*x1*x2'+c);
 
   KERNOBJ = prtKernelHyperbolicTangent(PROPERTY1, VALUE1, ...) constructs a
   prtKernelHyperbolicTangent object KERNOBJ with properties as specified by
   PROPERTY/VALUE pairs. prtKernelHyperbolicTangent objects have the following
   user-settable properties:
 
    kappa   - Positive scalar value specifying the gain on the inner
              product between x1 and x2 (default 1)
 
    c       - Scalar value specifying DC offset in hyperbolic tangent
              function
 
   For more information on these kernels, please refer to:
    
   http://en.wikipedia.org/wiki/Support_vector_machine#Non-linear_classification
 
   prtKernelHyperbolicTangent objects inherit the TRAIN, RUN, and AND
   methods from prtKernel.
 
   % Example:
   ds = prtDataGenBimodal;
 
   k1 = prtKernelHyperbolicTangent;
   k2 = prtKernelHyperbolicTangent('kappa',2);
    
   k1 = k1.train(ds); % Train
   g1 = k1.run(ds); % Evaluate
 
   k2 = k2.train(ds); % Train
   g2 = k2.run(ds); % Evaluate
 
   subplot(2,2,1); imagesc(g1.getObservations);  %Plot the results
   subplot(2,2,2); imagesc(g2.getObservations);