帮忙来看看这个错误

lwwhlkk

程序是书上的，只不过将信号改变了一下，一运行就出现下面的错误，错误是出现在thr=wbmpen(c,l,sigma,alpha);该句上，由于本人水平太低，半天也没搞懂，还请大家帮忙指点指点，在此先表示感谢了！
[y,fs]=wavread('voice600.wav');
x=awgn(y,0,'measured');
figure(1);
subplot(311);plot(y);title('原始信号');
subplot(312);plot(x);title('加噪信号');
wname='sym6';
lev=5;
[c,l]=wavedec(x,lev,wname);
sigma=wnoisest(c,l,1);
alpha=2;
thr=wbmpen(c,l,sigma,alpha);
keepapp=1;
xd=wdencmp('gbl',c,l,wname,lev,thr,'s',keepapp);
subplot(313);plot(xd);title('降噪信号')
??? Error using ==> unknown
Matrix dimensions must agree.

Error in ==> wbmpen at 57
[dummy,indmin] = min(pen-rl2scr);

lwwhlkk

两天啦，咋没人呢，来人啊，快来人啊:@Q