Changes between Version 7 and Version 8 of Ticket #1291


Ignore:
Timestamp:
02/02/15 16:40:23 (6 years ago)
Author:
rws
Comment:

Some questions must be answered before doing this:

  • Where would this live, misc/?
  • Which way to represent recurrence relations,
    1. equations of indexed values (Maxima);
    2. equations of function expressions (Sympy);
    3. a dedicated class/ring like in #15714?
  • Who commits to the review?

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  • Ticket #1291 – Description

    v7 v8  
    1 Sage should be able to easily solve at least some recurrences.  Maxima is actually pretty capable here.
     1This ticket would provide an interface to Maxima's and Sympy's recurrence-solving functions.
     2
     3Maxima example:
    24{{{
    35sage: maxima.load('solve_rec')
    … …  
    1315}}}
    1416
     17Sympy example:
     18{{{
     19>>> from sympy import Function, rsolve
     20>>> from sympy.abc import n
     21>>> y = Function('y')
    1522
    16 Somebody should wrap this:
     23>>> f = (n - 1)*y(n + 2) - (n**2 + 3*n - 2)*y(n + 1) + 2*n*(n + 1)*y(n)
     24
     25>>> rsolve(f, y(n))
     262**n*C0 + C1*factorial(n)
     27
     28>>> rsolve(f, y(n), { y(0):0, y(1):3 })
     293*2**n - 3*factorial(n)
     30}}}
     31The Maxima help:
    1732{{{
    1833
    … …  
    93108  Try `?? solve_rec' to see them.
    94109}}}
    95 Since there is also `sympy.rsolve` which is quite capable, this ticket should wrap both maxima and sympy.