[GiNaC-list] quo behaviour

Ralf Stephan ralf at ark.in-berlin.de
Wed Aug 18 12:21:04 CEST 2004

> I guess one needs to re-express quo()/rem() in terms of pquo()/prem() to
> make that work?

Only your question made me aware of prem(). Now, that seems possible
but prem() itself appears to have problems:

> prem(x*y^3,y*x^3,x);

This would (according to the tutorial) satisfy 
x^(-3)*x*y^3 = y*x^3*q + prem (=x*y^3), so 
q = pquo() = (x^(-3)-1)*y^2/x^2 which doesn't seem right.

There is also the problem of quo() returning a fail (decompose_rational() 
needs it) which surprised my computations, giving an error, something with 
commutativity, and I needed some time to see that I was working with a fail
that I got from quo(). 


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