ASKSAGE: Sage Q&A Forum - Latest question feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Fri, 03 Apr 2015 09:09:37 -0500- bug in the pq-trees library ?https://ask.sagemath.org/question/26435/bug-in-the-pq-trees-library/For the following PQ-tree named pqtree:
('P', [{3, 5, 7}, {4, 7}, {1, 7}, {3}, {6}, ('Q', [('P', [{0, 1, 3, 4}, {0, 6}]), {0, 2, 5}, ('P', [{2}, {2, 6}])])])
The command set_contiguous(4) gives:
sage: pqtree.set_contiguous(4)
(1, True)
sage: pqtree
('P', [{3, 5, 7}, {1, 7}, {3}, {6}, ('Q', [('P', [{2}, {2, 6}]), {0, 2, 5}, ('P', [{0, 6}, {0, 1, 3, 4}]), {4, 7}])])
Observe that the subset including 4 are not necessarily contiguous in this PQ-tree! Repeating the command gives:
sage: pqtree.set_contiguous(4)
(1, True)
sage: pqtree
('P', [{3, 5, 7}, {1, 7}, {3}, {6}, ('Q', [('P', [{2}, {2, 6}]), {0, 2, 5}, {0, 6}, {0, 1, 3, 4}, {4, 7}])])
Now it is OK, but we need to repeat twice the command.
olivierFri, 03 Apr 2015 09:09:37 -0500https://ask.sagemath.org/question/26435/