#9794: Make easy wrapper for symbolic lagrange interpolation
---------------------------+------------------------------------------------
Reporter: kcrisman | Owner: burcin
Type: enhancement | Status: new
Priority: major | Milestone: sage-4.6
Component: symbolics | Keywords:
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Currently, one has to do something like one of these.
{{{
> 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 :) (see
http://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
}}}
That's too bad; we need to wrap this to make it very easy to get the
interpolation from a list of points with one command from SR.
One thing to discuss would be whether one would want an approximate one if
the coefficients were floats/RR, or always to try for an exact one.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9794>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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