I'm actually working on a slightly different type of interval compare for the p-adics. Lazy p-adics will return an interval as their valuation if they're currently indistinguishable from 0: it will be of the form [a, infinity] or [a, a]. If you compare such intervals, they shrink themselves until either they can separate themselves from the other interval you're comparing with, they both become single points and are equal, or they give up after some amount of trying and raise an error (to stop the comparison from running forever in the case that both values are secretly zero). You can then do arithmetic with such intervals (when multiplying, they can shrink themselves away from multiplying zero by infinity, etc). This is all being a real pain to implement, but if people are interested in these types of objects in more generality than just as the valuations of lazy p-adics and power series, you should let me know so I can take your application into account in the design. David
On Feb 12, 2:38 am, "Michel" <[EMAIL PROTECTED]> wrote: > I am wondering what Sage's strategy is with regard to coercions. > It thought that it would be reasonable that an element of a > RealIntervalField > should be coercable into a RealField but this does not seem to be the > case. > > sage: r=RealIntervalField(16)((1,2)) > sage: RealField(16)(r) > > <type 'exceptions.TypeError'>: Unable to convert x > (='[1.00000...2.00000]') to real number. > > Is this a design decision? > > Regards, > Michel --~--~---------~--~----~------------~-------~--~----~ 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-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
