#20693: Sage crashes when computing newforms
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Reporter: ehlen | Owner:
Type: defect | Status: new
Priority: critical | Milestone: sage-7.3
Component: modular forms | Resolution:
Keywords: | Merged in:
Authors: Stephan Ehlen | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Comment (by pbruin):
To investigate the crash, it may help to add `sig_on()...sig_off()` around
the NTL calls in
`sage.rings.number_field.number_field_element.NumberFieldElement._invert_c_()`.
For the slowdown, I tried the following with increasing weights:
{{{
sage: G = DirichletGroup(17)
sage: %prun Newforms(G[2], 8, names='a')
}}}
Indeed, the method `dual_eigenvector()` takes up more and more of the
time; more precisely, most of it is spent in a number of calls to the PARI
function `eltreltoabs()`:
{{{
403 21.366 0.053 21.366 0.053 {method '_eltreltoabs' of
'sage.libs.pari.gen.gen' objects}
17 1.843 0.108 2.290 0.135 {method 'echelon_form' of
'sage.matrix.matrix_cyclo_dense.Matrix_cyclo_dense' objects}
1 1.706 1.706 1.963 1.963 {method 'nonpivots' of
'sage.matrix.matrix0.Matrix' objects}
1 1.549 1.549 4.381 4.381 {method 'height' of
'sage.matrix.matrix_cyclo_dense.Matrix_cyclo_dense' objects}
1 1.135 1.135 24.522 24.522
module.py:1076(dual_eigenvector)
4056 0.603 0.000 14.743 0.004 matrix_space.py:1270(matrix)
72532/72531 0.477 0.000 0.928 0.000
number_field.py:9303(_element_constructor_)
65119/65111 0.457 0.000 1.202 0.000
polynomial_ring_constructor.py:50(PolynomialRing)
[...]
}}}
Perhaps #18727, #18740 and/or #252 could be relevant for this problem?
--
Ticket URL: <http://trac.sagemath.org/ticket/20693#comment:9>
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