In the polynomial division, such as b(x)/a(x)=q(x)+r(x)/b(x) or
b(x)=a(x)q(x)+r(x)
where we denote length of b,a,q,r as Lb,La,Lq,Lr, respectively.

Then using the built-in function,
[q,r]=deconv(b,a)
We get our desired answers: q,r,

However, it is Lr=Lb instead of Lr=La-1 for La<Lb.
The unwanted data ahead the desired r should be completely eliminated, even they are very very small..

The presented function
[q,r]=deconv_e(b,a)
will resolve this problem,