#10004: The gap instances in a parallelised function do not always have distinct
_local_tmpfile
--------------------------+-------------------------------------------------
Reporter: SimonKing | Owner: was
Type: defect | Status: new
Priority: blocker | Milestone: sage-4.6.1
Component: interfaces | Keywords: _local_tmpfile, parallel
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Using the {...@parallel}}} decorator on a function, the Gap instances in
the different branches of the function should have distinct files for I/O.
Indeed, under normal circumstances, they are distinct:
{{{
sage: @parallel
....: def f(n):
....: return gap._local_tmpfile()
....:
sage: L = [t[1] for t in f(range(5))]
sage: len(set(L)) # this is how it should be
5
}}}
However, it suffices to call {{{gap._local_tmpfile()}}} in the main sage
branch in order to break diversity:
{{{
sage: print gap._local_tmpfile()
/home/king/.sage//temp/gauss/16041//interface//tmp16041
sage: L = [t[1] for t in f(range(5))]
sage: len(set(L)) # this is how it must not be
1
}}}
The consequences are obvious: Having different processes use the same file
for passing command lines must end in a disaster.
I hope it is OK to mark this as blocker. After all, parallelisation and
interfaces are both important.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10004>
Sage <http://www.sagemath.org>
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