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function k = svkernelv(ker,u,v) 
%SVKERNELV kernel for Support Vector Methods 
% 
%  Usage: k = svkernelv(ker,u,v) 
% 
%  Parameters: ker - kernel type 
%              u,v - kernel arguments 
%              k   - vector of tensor product components 
% 
%  Values for ker: 'linear'  - 
%                  'poly'    - p1 is degree of polynomial 
%                  'rbf'     - p1 is width of rbfs (sigma) 
%                  'sigmoid' - p1 is scale, p2 is offset 
%                  'spline'  - 
%                  'bspline' - p1 is degree of bspline 
%                  'fourier' - p1 is degree 
%                  'erfb'    - p1 is width of rbfs (sigma) 
%                  'anova'   - p1 is max order of terms 
%               
%  Author: Steve Gunn (srg@ecs.soton.ac.uk) 
 
  if (nargin < 1) % check correct number of arguments 
     help svkernel 
  else 
      
    global p1 p2; 
 
    % could check for correct number of args in here 
    % but will slow things down further 
    switch lower(ker) 
      case 'curvspline' 
        k = u.*v.*min(u,v) - ((u+v)/2).*(min(u,v)).^2 + (1/3)*(min(u,v)).^3; 
      case 'anovaspline1' 
        k = u.*v + u.*v.*min(u,v) - ((u+v)/2).*(min(u,v)).^2 + (1/3)*(min(u,v)).^3; 
      case 'anova' 
        k = u.*v + (1/2)*u.*v.*min(u,v) - (1/6)*(min(u,v)).^3; 
      case 'anovaspline2' 
        k = u.*v + (u.*v).^2 + (u.*v).^2.*min(u,v) - u.*v.*(u+v).*(min(u,v)).^2 + (1/3)*(u.^2 + 4*u.*v + v.^2).*(min(u,v)).^3 - (1/2)*(u+v).*(min(u,v)).^4 + (1/5)*(min(u,v)).^5; 
      case 'anovaspline3' 
        k = u.*v + (u.*v).^2 + (u.*v).^3 + (u.*v).^3.*min(u,v) - (3/2)*(u.*v).^2.*(u+v).*(min(u,v)).^2 + u.*v.*(u.^2 + 3*u.*v + v.^2).*(min(u,v)).^3 - (1/4)*(u.^3 + 9*u.^2.*v + 9*u.*v.^2 + v.^3).*(min(u,v)).^4 + (3/5)*(u.^2 + 3*u.*v + v.^2).*(min(u,v)).^5 - (1/2)*(u+v).*(min(u,v)).^6 + (1/7)*(min(u,v)).^7; 
      case 'anovabspline' 
        k = 0; 
        for r = 0: 2*(p1+1) 
          k = k + (-1)^r*binomial(2*(p1+1),r)*(max(0,u-v + p1+1 - r)).^(2*p1 + 1); 
        end 
      otherwise 
        k = u.*v; 
    end 
 
  end