Karim Belabas on Mon, 10 Apr 2006 10:18:19 +0200 |
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Re: Pol problem (bug?) |
* Joerg Arndt [2006-04-09 11:27]: > I do not see a system here: > > ? Pol([a,b,c]) > a*x^2 + b*x + c > ? Pol([a,b,c],d) > a*d^2 + b*d + c > ? Pol([a,b,c],x) > a*x^2 + b*x + c > ? Pol([a,x,c]) > a*x^2 + x*x + c > ? Pol([a,x,c],'x) > a*x^2 + x*x + c > > ? Pol([a,x,c],'x_) > *** Pol: main variable has highest priority in gtopoly. > ? Pol([a,x,c],'a_) > *** Pol: main variable has highest priority in gtopoly. > ? Pol([a,x,c],'z_) > *** Pol: main variable has highest priority in gtopoly. I have reworded the error message and fixed an off-by-1 problem. The correct behaviour (current CVS, clean session) is ? Pol([a,b,c]) %1 = a*x^2 + b*x + c ? Pol([a,b,c],d) *** Pol: variable must have higher priority in gtopoly. ? Pol([a,b,c],x) %2 = a*x^2 + b*x + c ? Pol([a,x,c]) *** Pol: variable must have higher priority in gtopoly. ? Pol([a,x,c],'x) *** Pol: variable must have higher priority in gtopoly. ? Pol([a,x,c],'x_) *** Pol: variable must have higher priority in gtopoly. ? Pol([a,x,c],'a_) *** Pol: variable must have higher priority in gtopoly. ? Pol([a,x,c],'z_) *** Pol: variable must have higher priority in gtopoly. > what is a "main variable"? (09:38) gp > ??Pol Pol(x,{v = x}): transforms the object x into a polynomial with main variable v. [...] Warning: this is not a substitution function. It will not transform an object containing variables of higher priority than v. ? Pol(x + y, y) *** Pol: variable must have higher priority in gtopoly. See also Section 2.5.4 (p. 39, current CVS) of the User's manual, on "Variable priorities, multivariate objects" > There does not seem to be a workaround. There might be. What are you trying to achieve ? Cheers, K.B. -- Karim Belabas Tel: (+33) (0)5 40 00 26 17 Universite Bordeaux 1 Fax: (+33) (0)5 40 00 69 50 351, cours de la Liberation http://www.math.u-bordeaux.fr/~belabas/ F-33405 Talence (France) http://pari.math.u-bordeaux.fr/ [PARI/GP]