On Aug 24, 10:51 am, Jason Grout <[email protected]> wrote: > On 08/24/2010 09:03 AM, kcrisman wrote: > > Dear sage-devel, > > > > I have two things I just want confirmation of before I file tickets - > > such as an alternate way/workaround to do these things which I have > > missed. Thanks for any replies. > > > > - kcrisman > > > > 1. There is no way to get a symbolic interpolated polynomial de novo > > without going through polynomial rings, e.g. all these steps: > > > > pts = [(1,2),(2,3),(3,2),(4,3),(5,2),(6,3)] > > R.<x>=QQ[] > > f = R.lagrange_polynomial(pts) > > SR(f) > >
> Yes. You could define your own function :) > (seehttp://sage.cs.drake.edu/home/pub/2/, for example). Also, mpmath and > numpy/scipy can get numerical values for the coefficients, I believe. > Maxima also can construct a lagrange polynomial (load the 'interpol' > package) > sage: maxima.load('interpol') > "/home/jason/sage-4.4.2/local/share/maxima/5.20.1/share/numeric/interpol.ma c" > sage: maxima.lagrange([[1,2],[3,4]]) > -x+2*(x-1)+3 Okay, okay! I just wanted to make sure. Wrapping one or both of these should be sufficient. For tomorrow I just hacked it :) > > > 2. If one has a non-symbolic polynomial currently, it won't plot with > > the new plotting syntax. > > > > plot(f,0,5) # works, old-school Sage > > plot(f,(x,0,5)) # doesn't work, new-school Sage > > plot(f,x,0,5) # doesn't work, though sort of makes sense it shouldn't > > since x isn't a symbolic variable now... ? > > > > If there was a direct interpolated polynomial for SR I wouldn't have > > noticed the second one. > > > > This seems like a bug, if 'f' is a Sage polynomial and 'x' is the > corresponding variable. > Thanks. - kcrisman -- To post to this group, send an email to [email protected] To unsubscribe from this group, send an email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
