|Bill Allombert on Sun, 20 Jun 2004 19:29:41 +0200|
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On Sun, Jun 20, 2004 at 04:21:27PM +0200, Ralf Stephan wrote: > I am not sure if I understand what Bill writes about the new > behaviour of subst. The version is 2.2.8 from June 3. > > ? subst(x^3+1,x+1,x-1) > %3 = x^3 - 6*x^2 + 12*x - 7 > ? subst(x^3+y^3,x+y,x-y) > %4 = x^3 - 6*y*x^2 + 12*y^2*x - 7*y^3 > > Is this supposed to work? The changes was made on 2004/06/15. Before that date, this was supposed to work with the unstable branch only. Now, you should use substpol instead. ? subst(x^3+1,x+1,x-1) *** variable name expected: subst(x^3+1,x+1,x-1) ^-------- ? substpol(x^3+1,x+1,x-1) %1 = x^3 - 6*x^2 + 12*x - 7 One of the reason of the change is to keep the error message when you inadvertently use a polynomial instead of a variable. Cheers, Bill.