What is the reason to have such a bugged function? When can we trust it?
On 9 Mar, 14:18, Stan Schymanski <schym...@gmail.com> wrote: > Just a word of caution with respect to simplify_full(). > > If your function involves floating point numbers, simplify_full() can > give an erroneous result (see bug #2604950 in Maxima > orhttp://groups.google.com/group/sage-devel/browse_thread/thread/561309...). > > Also the following example shows a wrong result returned by > simplify_full() even without floats. > > ---------------------------------------------------------------------- > | Sage Version 3.3, Release Date: 2009-02-21 | > | Type notebook() for the GUI, and license() for information. | > ---------------------------------------------------------------------- > sage: var('omgo zr ys cz') > (omgo, zr, ys, cz) > sage: omgo = (sqrt(-zr^2 + 2*ys*zr + (2*cz - zr)^2 - 2*ys*(2*cz - zr)) > + 2*zr- 2*cz)/(2*zr - 2*cz) > sage: omgo.simplify_full() > (I*sqrt(cz - ys)*sqrt(zr - cz) + zr - cz)/(zr - cz) > > Now plucking in a few numbers for the variables shows that the results > before and after simplification are very different. > > sage: omgo(cz=10,ys=5,zr=4).n() > 0.0871290708247230 > sage: omgo.simplify_full()(cz=10,ys=5,zr=4).n() > 1.91287092917528 > > This is taken from the following > thread:http://groups.google.com/group/sage-support/browse_thread/thread/5d8e... > > My personal conclusion is to stay away from simplify_full() until I > know when to expect correct results from it. > > Stan > > On Jan 20, 10:56 am, Jason Grout <jason-s...@creativetrax.com> wrote: > > > Tim Lahey wrote: > > > However, in my version of Sage (3.2), the functions simplify_full() > > > and simplify_trig() only seem to be defined on objects not as > > > general functions. Unless I'm missing something. > > > I noticed that too. Does anyone object to making at least simplify_full > > a top-level function? > > > Jason --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
