kernel_maps.py 文件源码

def _Gram(self, X):
        if X is self.X:
            if self.Gs_train is None:
                kernel_scalar = rbf_kernel(self.X, gamma=self.gamma)[:, :,
                                                                     newaxis,
                                                                     newaxis]
                delta = subtract(X.T[:, newaxis, :], self.X.T[:, :, newaxis])
                self.Gs_train = asarray(transpose(
                    2 * self.gamma * kernel_scalar *
                    (eye(self.p)[newaxis, newaxis, :, :] - 2 *
                        (self.gamma * delta[:, newaxis, :, :] *
                            delta[newaxis, :, :, :]).transpose((3, 2, 0, 1))),
                    (0, 2, 1, 3)
                )).reshape((self.p * X.shape[0], self.p * self.X.shape[0]))
            return self.Gs_train

        kernel_scalar = rbf_kernel(X, self.X, gamma=self.gamma)[:, :,
                                                                newaxis,
                                                                newaxis]
        delta = subtract(X.T[:, newaxis, :], self.X.T[:, :, newaxis])
        return asarray(transpose(
            2 * self.gamma * kernel_scalar *
            (eye(self.p)[newaxis, newaxis, :, :] - 2 *
                (self.gamma * delta[:, newaxis, :, :] *
                    delta[newaxis, :, :, :]).transpose((3, 2, 0, 1))),
            (0, 2, 1, 3)
        )).reshape((self.p * X.shape[0], self.p * self.X.shape[0]))