#11476: PartitionTuples.cardinality has problems
---------------------------------+------------------------------------------
Reporter: pdehaye | Owner: sage-combinat
Type: defect | Status: new
Priority: major | Milestone: sage-5.4
Component: combinatorics | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Comment (by andrew.mathas):
This seems to be a bug in pari. I found a web page a few weeks ago
suggesting that this might be an integer overflow problem in pari, but I
have not succeeded in finding this page now... I have emailed the pari
support group to ask them about it.
This failure appears much earlier than the example above suggests:
{{{
sage: PartitionTuples(17,2).cardinality()
...
TypeError: unable to convert x (= *** at top-level:
polcoeff(1/eta(x)^2,
*** ^--------------------
*** polcoeff: non existent component in truecoeff.) to an integer
}}}
If you run pari natively you get the error more quickly:
{{{
Desktop: sage -gp
GP/PARI CALCULATOR Version 2.5.2
(development git-b703ee3)
i386 running darwin (x86-64/GMP-5.0.2 kernel)
64-bit version
compiled: Sep 12 2012, gcc-4.6.3
(GCC)
(readline v6.2 enabled, extended help
enabled)
Copyright (C) 2000-2011 The PARI
Group
PARI/GP is free software, covered by the GNU General Public License, and
comes WITHOUT ANY WARRANTY WHATSOEVER.
Type ? for help, \q to quit.
Type ?12 for how to get moral (and possibly technical) support.
parisize = 8000000, primelimit = 500509
? polcoeff(1/eta(x)^2, 16, x)
%1 = 5822
? polcoeff(1/eta(x)^2, 17, x)
*** at top-level: polcoeff(1/eta(x)^2,
*** ^--------------------
*** polcoeff: non existent component in truecoeff.
*** Break loop: type 'break' to go back to GP
}}}
This is a little surprising as the number of 2-tuples of partitions adding
to 17 is 8470, which isn't that big.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11476#comment:1>
Sage <http://www.sagemath.org>
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