gusucode.com > 《模式识别与智能计算》matlab源代码 > 《模式识别与智能计算》matlab源代码/《模式识别与智能计算》部分函数的源程序/书程序/第6章/kernel.m
function [K] = kernel(ker,x,y) switch ker.type case 'linear' K = x'*y; case 'ploy' d = ker.degree; c = ker.offset; K = (x'*y+c).^d; case 'gauss' s = ker.width; rows = size(x,2); cols = size(y,2); tmp = zeros(rows,cols); for i = 1:rows for j = 1:cols tmp(i,j) = norm(x(:,i)-y(:,j)); end end K = exp(-0.5*(tmp/s).^2); case 'tanh' g = ker.gamma; c = ker.offset; K = tanh(g*x'*y+c); otherwise K = 0; end