#16137: lazy_list from various input data
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Reporter: MatthieuDien | Owner:
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-7.0
Component: misc | Resolution:
Keywords: LazyPowerSeries, | Merged in:
lazy_list, days57 | Reviewers: Daniel Krenn
Authors: Matthieu Dien, | Work issues:
Vincent Delecroix, Daniel Krenn | Commit:
Report Upstream: N/A | 72a212c34c0f2a172b9d7ac95d11f24d254a86c3
Branch: u/dkrenn/16137 | Stopgaps:
Dependencies: |
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Comment (by vdelecroix):
It is perfectly fine to use `lazy_list` recursively. With your example one
option is
{{{
from sage.data_structures.lazy_list import lazy_list_generic
class MySerie(lazy_list_generic):
def __init__(self):
lazy_list_generic.__init__(self, cache=[1])
self._n = 0
def _new_slice(self):
n = self._n
self._n += 1
return [sum(self.get(i) * self.get(n-i) for i in range(n+1))]
}}}
then
{{{
sage: f = MySerie()
sage: f[0]
1
sage: f[1]
1
sage: f[2]
2
sage: f[3]
5
sage: f[4]
14
sage: f[5]
42
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/16137#comment:100>
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