#17376: Cleanup subgraphsearch to avoid crashes
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Reporter: ncohen | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.5
Component: graphics | Keywords:
Merged in: | Authors: Nathann Cohen
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Commit: | Dependencies:
Stopgaps: |
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The !SubgraphSearch code crashes from time to time when you Ctrl+C it
during its memory allocation instructions.
This patch cleans the code a bit so that all allocations happen in one
place, before the actual code is run. And so `__dealloc__` only frees the
memory that has been allocated, even if the code was interrupted.
Basically, we avoid crashed only with simple code cleaning.
1) In order to produce the crash, run this and CTRL+C it immediately:
{{{
graphs.CompleteMultipartiteGraph([20,20,20,20]).subgraph_search(graphs.CompleteGraph(5))
}}}
Do it several times in a row if necessary.
2) The code could use a rewrite with bitsets. It would be faster and
lighter in memory, but there is already a pretty similar code in
`needs_review` at #17309 and I fear that it may take time before it is
reviewed. So I will wait for this before reimplementing SubgraphSearch.
--
Ticket URL: <http://trac.sagemath.org/ticket/17376>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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