Documentation of prem()

Christian Bauer cbauer at thep.physik.uni-mainz.de
Mon Sep 23 16:50:06 CEST 2002


Hi!

On Sat, Sep 21, 2002 at 04:21:08PM +0200, Tatiana Zolo wrote:
> the documentation about the function prem() (section 5.5.3 of GiNaC
> 1.0.11) says that the pseudo-remainder of 'a' and 'b' satisfies
> c*a = b*q + prem(a, b, x), where c = b.lcoeff(x)^(a.degree(x) -
> b.degree(x) + 1).
> 
> I think there is maybe a mistake (probably a printing mistake), the
> formula should be
> c*a = c*b*q + prem(a, b, x), where c = b.lcoeff(x)^(a.degree(x) -
> b.degree(x) + 1).

Well, it depends... I never specified what 'q' is. :-) It's not quo(a,b,x),
but the pseudo-quotient of a(x) and b(x) (which isn't always equal to c*q,
either). Maybe I should add a pquo() function to GiNaC (or have prem()
optionally return the pseudo-quotient)?

Bye,
Christian

-- 
  / Coding on PowerPC and proud of it
\/ http://www.uni-mainz.de/~bauec002/



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