#6441: [with patch, needs work] Charpoly (plus adjoint and det)
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Reporter: spancratz | Owner: somebody
Type: defect | Status: new
Priority: minor | Milestone: sage-4.1.2
Component: linear algebra | Keywords: charpoly, division-free
Reviewer: | Author: Sebastian Pancratz
Merged: |
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Comment(by rbeezer):
Sebastian,
I'll second Yann's suggestion above. The arrays a, A and F all have the
index t fixed in the second location, and the F array is initalized each
time t increments with its previous values, so these values can just
rollover. Thus these main arrays this could all be one dimension smaller,
notably a. Then the storage requirement for the algorithm is roughly the
same as for the matrix (assuming it is dense), rather than being a factor
of n larger, which could be problematic for very large matrices. And the
code seems correspondingly simpler to read and understand.
I've looked over how this gets used (determinant, adjoint, etc) and if the
main algorithm and its effects were isolated in a patch separate from the
unrelated documentation clean-ups then I ought to be able to finish off
the review without too much more work.
Rob
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/6441#comment:12>
Sage <http://sagemath.org/>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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