How do you know for sure if something is not equal and that we are just not lacking an advanced enough simplifier? For trivial cases this will work and it will have to throw exceptions for everything else.
On Wed, Jun 4, 2008 at 6:17 PM, Robert Bradshaw <[EMAIL PROTECTED]> wrote: > > On Jun 4, 2008, at 5:05 PM, Gary Furnish wrote: > >> Errors should not under any circumstances be thrown if bool(x==y) is >> inconclusive. It would break half of the code that depends on >> symbolics, and would require try blocks around every if statement. > > Can you give an example of something that would break? The point is > that one wouldn't catch the error--if one is branching on a condition > that is undetermined then the error should be propagated upwards. > > - Robert > > >> >> On Wed, Jun 4, 2008 at 5:57 PM, Carl Witty <[EMAIL PROTECTED]> >> wrote: >>> >>> On Jun 4, 4:16 pm, Robert Bradshaw <[EMAIL PROTECTED]> >>> wrote: >>>> On Jun 4, 2008, at 2:46 PM, Jason Grout wrote: >>>> >>>>> Of course, bool(some equation) returning False does not necessarily >>>>> mean >>>>> that the two expressions are not equal; it only means that we >>>>> couldn't >>>>> prove them to be equal using some simple simplifications. >>>> >>>>> From the docstring for _nonzero_ from equation.py (used to >>>>> implement >>>>> bool()): >>>> >>>>> Return True if this (in)equality is definitely true. Return False >>>>> if it >>>>> is false or the algorithm for testing (in)equality is inconclusive. >>>> >>>> Should it throw an error in this case? (Is there a way to know if >>>> the >>>> result was inconclusive?) >>> >>> In this thread: http://groups.google.com/group/sage-devel/ >>> browse_thread/thread/bcdc671d2791056e/e086a9d59ff4b9ba >>> it seems that the consensus was to throw an error here; but nobody >>> ever implemented it (or even opened a trac ticket, as far as I know). >>> >>> Carl >>>> >>> >> >> > > > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
