A colleague reported this, which looks like a bug to me. This is in Sage-5.1.rc0. Note that g.prec() is only 19 though f.prec() is Infinity.
John I'm not sure who to bother about this, so I thought I could ask you. Here is a version of a Sage behaviour (feature? bug?) that bit me recently. sage: R, x = PowerSeriesRing(ZZ, 'x', default_prec = 80).objgen() sage: f = x + x^2 sage: f.parent() Power Series Ring in x over Integer Ring sage: f.parent().default_prec() 80 sage: g = 1/f sage: g.parent() Laurent Series Ring in x over Integer Ring sage: g.parent().default_prec() 20 (??????) sage: h = 1/2 * f sage: h.parent() Power Series Ring in x over Rational Field sage: h.parent().default_prec() 80 That was a big surprise to me! Sometimes the precision is carried over to the new ring, and sometimes it isn't? Now that I've found this, I can catch it my code, but it does seem strange... It seems more reasonable for the precision to always be carried over? Am I confused here? best, saul -- -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
