|Bill Allombert on Thu, 4 Jul 2002 14:23:08 +0200|
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|Re: polcoeff() mystery|
On Tue, Jul 02, 2002 at 09:16:06AM -0400, Ilya Zakharevich wrote: > Do you mean that to have efficient polynomial arithmetic, it is enough > to insert enough calls to simplify(), as in > > T = simplify(x^2+y*x+z) > > ? > > > Hope this is clearer, > > Much clearer in some respects, much more obscure in others... There are three things to keep in mind: 1) GP know only about univariate polynomials over a field. 2) 'foo^0 is printed as 1 for every foo., but is internally still 'foo^0 3) The same happen for zero complex, quadratic and algebraic numbers. There is no such thing as x^2+y*x+z. What there is really is x^2+y*x+z*x^0, but eventually it can be x^2+y*x+z*y^0*x^0, x^2+z^0*y*x+z*y^0*x^0,etc... polcoeff(P,n) is exactly identical to Vec(P)[poldegree(P)-n+1] Maybe a print function that output 'foo^0 as 'foo^0 not 1 could be useful. Cheers, Bill.