kernels.py 文件源码

def deriveKernel(self, params, i):
        self.checkParamsI(params, i)
        c = np.exp(params[-1])

        #K = self.kernel.getTrainKernel(params[:-1])
        #deriv1 = self.polyDegree * (c+K)**(self.polyDegree-1)

        K = self.kernel.getTrainKernel(params[:-1]) + c     
        if (self.polyDegree==2): Kpower=K
        else:
            Kpower=K**2
            for i in xrange(self.polyDegree-3): Kpower*=K               #this is faster than direct power
        deriv1 = self.polyDegree * Kpower

        if (i==params.shape[0]-1): K_deriv = deriv1*c
        else:      K_deriv = deriv1 * self.kernel.deriveKernel(params[:-1], i)
        return K_deriv