Bill Allombert on Wed, 28 Jun 2006 18:45:52 +0200 |
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Re: divrem bug? |
On Wed, Jun 28, 2006 at 02:58:57PM +0200, Bernard Parisse wrote: > Hi! > > under pari 2.3.0, divrem(x+1,x^2,y) returns > %1 = [1/y^2*x + 1/y^2, 0] > > It should be something corresponding to [(x+1)/x^2, 0], > y should not occur there. Or is it not handled under pari? Well returning incorrect output is a bug but I would not expect divrem(x+1,x^2,y) to work because this breaks variable priorities. See the PARI manual, chapter 2, Variable priorities, multivariate objects (??"Variable priorities, multivariate objects"@2). If you want to work in K(x)[y] instead of K(y)[x], you need to define variables priorities so that x << y. Unfortunately, this is not possible with the 'x variable which has always highest priority, so the simplest is to do: ? Y;X;\\ Y >> X ? divrem(X+1,X^2,Y) %2 = [(X + 1)/X^2, 0]~ We have a long plan to allow the user to add new variables with specified priorities though... Cheers, Bill.