Kevin Ryde on Thu, 11 Dec 2014 09:38:05 +0100

[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

polynomial partial fractions

I had the urge to break some polynomial ratios into partial fractions.
I thought maybe a vector result of terms which sum to the original.

    p = x^4 / ((1-x)*(1-2*x)*(1 - x - 2*x^3))
    v = polynomial_crack_into_partial_fractions(p)
    v == [ (1/2) / (1-x),
           (1/2) / (1-2*x),
           - (1 + (1/2)*x + x^2) / (1-x-2*x^3) ]
    vecsum(v) == p

What would I look at for such a thing?  I know how to build a matrix for
matsolve() to give the numerators, but perhaps this exists already.
I saw Henri Cohen's ratdec() but it seems to go polroots()
where I had in mind only going as far as can be factorized exactly over
complex or quadratics (so leave the cubic above unchanged).  Could
supply the desired denominators if necessary.

No, eees hamster.