#6665: Expanding the 'zero' symmetric function in variables crashes symmetrica
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Reporter: jbandlow | Owner: mhansen
Type: defect | Status: new
Priority: major | Milestone:
Component: combinatorics | Keywords: symmetrica
Reviewer: | Author:
Merged: |
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Jerome Lefebvre reported:
{{{
Bizarre error reporting with symmetric functions;
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| Sage Version 4.1, Release Date: 2009-07-09 |
| Type notebook() for the GUI, and license() for information. |
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sage: H = SymmetricFunctionAlgebra(QQ, basis='homogeneous')
sage: f = H(0)
sage: print f
0
sage: g = f.expand(3, alphabet=['x_1','x_2','x_3'])
This then gives me;
enter a to abort with core dump, g to go, f to supress
s to supress further error text, r to retry, e to explain, else stop
ERROR: s_po_k: not POLYNOM?:
So I entered e (had to do it twice) to get;
enter a to abort with core dump, g to go, f to supress
s to supress further error text, r to retry, e to explain, else stop
ERROR: s_po_k: not POLYNOM?: e
enter a to abort with core dump, g to go, f to supress
s to supress further error text, r to retry, e to explain, else stop
ERROR: s_o_k:object == NULL?: e
---------------------------------------------------------------------------
NotImplementedError Traceback (most recent call
last)
/Users/jeromelefebvre/.sage/temp/Jerome.local/22022/
_Users_jeromelefebvre__sage_init_sage_0.py in <module>()
/Applications/sage/local/lib/python2.6/site-packages/sage/combinat/sf/
homogeneous.pyc in expand(self, n, alphabet)
95 """
96 condition = lambda part: False
---> 97 return self._expand(condition, n, alphabet)
98
99
/Applications/sage/local/lib/python2.6/site-packages/sage/combinat/sf/
sfa.pyc in _expand(self, condition, n, alphabet)
1534 resPR = PolynomialRing(parent.base_ring(), n,
alphabet)
1535 f = lambda part: resPR(0) if condition(part) else resPR
(e(part, n, alphabet))
-> 1536 return parent._apply_module_morphism(self, f)
1537
1538 def scalar(self, x):
/Applications/sage/local/lib/python2.6/site-packages/sage/combinat/
free_module.pyc in _apply_module_morphism(self, x, f)
973 res = 0
974 for m, c in x._monomial_coefficients.iteritems():
--> 975 res += c*f(m)
976 return res
977
/Applications/sage/local/lib/python2.6/site-packages/sage/combinat/sf/
sfa.pyc in <lambda>(part)
1533 e = eval('symmetrica.compute_' + str
(classical.translate[parent.basis_name()]).lower() + '_with_alphabet')
1534 resPR = PolynomialRing(parent.base_ring(), n,
alphabet)
-> 1535 f = lambda part: resPR(0) if condition(part) else resPR
(e(part, n, alphabet))
1536 return parent._apply_module_morphism(self, f)
1537
/Applications/sage/local/lib/python2.6/site-packages/sage/libs/
symmetrica/symmetrica.so in
sage.libs.symmetrica.symmetrica.compute_homsym_with_alphabet_symmetrica
(sage/libs/symmetrica/symmetrica.c:15628)()
/Applications/sage/local/lib/python2.6/site-packages/sage/libs/
symmetrica/symmetrica.so in
sage.libs.symmetrica.symmetrica._py_polynom_alphabet (sage/libs/
symmetrica/symmetrica.c:4777)()
/Applications/sage/local/lib/python2.6/site-packages/sage/libs/
symmetrica/symmetrica.so in sage.libs.symmetrica.symmetrica._py (sage/
libs/symmetrica/symmetrica.c:2203)()
NotImplementedError: -6
sage:
}}}
This is related to #6487, and the fact that symmetrica typically segfaults
with input it doesn't expect.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/6665>
Sage <http://sagemath.org/>
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