Some code for Lagrange inversion has been posted on the "generic power
series reversion" trac ticket: http://trac.sagemath.org/sage_trac/ticket/7644
The code doesn't quite run, since it references some other function
(ps_coefficient); here's an updated version which uses only built-in
functions:
On Wed, Dec 9, 2009 at 10:50 AM, Matt Bainbridge
wrote:
> Its easy enough to code this in sage. This seems to work over any
> field:
Thanks. This is now http://trac.sagemath.org/sage_trac/ticket/7644
>
>
> def ps_inverse(f):
> if f.prec() is infinity:
> raise ValueError, "series must
Its easy enough to code this in sage. This seems to work over any
field:
def ps_inverse(f):
if f.prec() is infinity:
raise ValueError, "series must have finite precision for
reversion"
if f.valuation() != 1:
raise ValueError, "series must have valuation one for
reversion"
William Stein writes:
> On Mon, Dec 7, 2009 at 11:04 AM, Matt Bainbridge
> wrote:
>> Thanks, William!
>>
>> I guess so far it only works over Q?
>>
>> --Matt
>>
>
> It calls off to PARI, so it probably works (or can trivially be made
> to work) over any base that PARI supports.
In case it do
On Mon, Dec 7, 2009 at 11:04 AM, Matt Bainbridge
wrote:
> Thanks, William!
>
> I guess so far it only works over Q?
>
> --Matt
>
It calls off to PARI, so it probably works (or can trivially be made
to work) over any base that PARI supports. In case it isn't
implemented in general in sage, it wo
Thanks, William!
I guess so far it only works over Q?
--Matt
On Dec 7, 7:43 pm, William Stein wrote:
> 2009/12/7 Matt Bainbridge :
>
> > Hi there,
>
> > Does anyone know if Sage has a function for computing the composition
> > inverse of a power series (not the reciprocal)?
>
> Yep, we have t
