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### Highlights from Polynomial division - derived form covolution

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# Polynomial division - derived form covolution

### Feng Cheng Chang (view profile)

10 Oct 2011 (Updated )

Polynomial division is derived directly from convolution.

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Description

For the division of univariate polynomials, given the dividend b(x) of degree n and the divisor a(x) of degree m, such that b(x) = q(x)*a(x) + r(x), the quotient q(x) of degree n-m and the remainder r(x) of degree m-1 are then obtained.

This very short code is similar to the MATLAB built-in function 'deconv.m'.

The presented routine [q,r] = poly_div(b,a) can avoid the un-wanted data preceeding the remaider's coefficients applying the built-in routine [q,r] = deconv(b,a). See author's self comment.

Acknowledgements

Polynomial Division By Convolution Quotient And Reminder inspired this file.

MATLAB release MATLAB 6.5 (R13)
11 Sep 2012 Feng Cheng Chang

### Feng Cheng Chang (view profile)

Self comment:
For example,
>
> b = [2 7 -5 9 -3], a = [3 -5 9 -2],
b =
2 7 -5 9 -3
a =
3 -5 9 -2

> [q,r] = poly_div(b,a),
q =
0.66667 3.4444
r =
6.2222 -20.667 3.8889

> [q,r] = deconv(b,a),
q =
0.66667 3.4444
r =
0 -8.8818e-016 6.2222 -20.667 3.8889
>
It shows that running the MATLAB built-in routine yields the unwanted data, even it is very very small.

Comment only