#19365: Bug in lattice_polytope.positive_integer_relations
-------------------------+-------------------------------------------------
Reporter: | Owner:
tmonteil | Status: needs_work
Type: | Milestone: sage-6.10
defect | Resolution:
Priority: major | Merged in:
Component: | Reviewers: Andrey Novoseltsev, Thierry
geometry | Monteil
Keywords: | Work issues:
Authors: | Commit:
Vincent Delecroix | 651684a41026bee07a49be83b238b059e72693bc
Report Upstream: N/A | Stopgaps:
Branch: |
public/19365 |
Dependencies: |
-------------------------+-------------------------------------------------
Changes (by tmonteil):
* status: positive_review => needs_work
* reviewer: Andrey Novoseltsev => Andrey Novoseltsev, Thierry Monteil
Comment:
The example provided in the doc is:
{{{
sage: points = [(1,1,-1,-1,-1), (-1,-1,1,1,-1), (1,-1,-1,-1,1),
....: (-1,1,1,1,1), (1,-1,1,-1,-1)]
sage: positive_integer_relations(points)
[(1, 0, 0, 1, 0)]
}}}
Could you explain how `(1,1,-1,-1,-1) + (-1,1,1,1,1) == 0` ?
The result should be `[(1, 1, 1, 1, 0)]`, see the ask question for the
expected answer.
Given a list of tuples, is it more natural to interpret it as a list of
vectors, or as a list of rows of a matrix whose columns are vectors ? We
might argue that the doc says that the points "are given as columns of a
matrix". But when the doc writes `points = [(1,1,-1,-1,-1),
(-1,-1,1,1,-1), (1,-1,-1,-1,1), (-1,1,1,1,1), (1,-1,1,-1,-1)]`, should the
user consider this as a natural way to define the vectors `[(1, -1, 1, -1,
1), (1, -1, -1, 1, -1), (-1, 1, -1, 1, 1), (-1, 1, -1, 1, -1), (-1, -1, 1,
1, -1)]` ?
It could be even worse if the user explicitely writes `points =
[vector([1,1,-1,-1,-1]), vector([-1,-1,1,1,-1]), vector([1,-1,-1,-1,1]),
vector([-1,1,1,1,1]), vector([1,-1,1,-1,-1])]` so that no ambiguity
appears on her side, but the first line of the code `M = matrix(points)`,
silently forgot all this information.
--
Ticket URL: <http://trac.sagemath.org/ticket/19365#comment:10>
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