#5402: Sparse determinants are slow
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Reporter: jbandlow | Owner: was
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-5.6
Component: linear algebra | Resolution:
Keywords: determinant | Work issues:
Report Upstream: N/A | Reviewers:
Authors: Charles Bouillaguet | Merged in:
Dependencies: | Stopgaps:
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Comment (by Bouillaguet):
There is an example of caching (the one I just mimicked...) in
matrix_sparse.pyx in the definition of charpoly().
I checked that caching works by computing a large sparse determinant twice
: the first call takes a few seconds, while the second call returns
instantly.
For the sake of easy reviewing :-) here is the code of charpoly() :
{{{
#!python
def charpoly(self, var='x', **kwds):
f = self.fetch('charpoly')
if f is not None:
return f.change_variable_name(var)
f = self.dense_matrix().charpoly(var=var, **kwds)
self.cache('charpoly', f)
return f
}}}
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/5402#comment:11>
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