#4757: eigenspaces_right over CDF gives total nonsense
----------------------------+-----------------------------------------------
Reporter: was | Owner: was
Type: defect | Status: new
Priority: major | Milestone: sage-3.2.2
Component: linear algebra | Keywords:
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I don't care what anybody says, this is a BUG. Either the command should
immediately raise a NotImplementedError, or it should give meaningful
output (e.g., not vector spaces of dimension 0!)
{{{
sage: a = random_matrix(CDF,2)
sage: a.eigenspaces_right()
[
(1.68954005899 + 0.570924387184*I, Vector space of degree 2 and dimension
0 over Complex Double Field
User basis matrix:
[]),
(-0.0345737707895 + 0.485480056628*I, Vector space of degree 2 and
dimension 0 over Complex Double Field
User basis matrix:
[])
]
}}}
We easily and quickly have the eigenvectors and eigenvalues in this case,
so I don't see what the problem is:
{{{
sage: a.eigenvectors_right()
([1.68954005899 + 0.570924387184*I, -0.0345737707895 + 0.485480056628*I],
[ 0.800587795941 0.758354735061]
[ 0.545800288485 - 0.24730795798*I -0.194687766428 + 0.622089036565*I])
}}}
Same comments for eigenspaces_left.
Note that oddly a.eigenspaces() gives a sensible answer though neither
left nor right does.
{{{
sage: a.eigenspaces_right()
[
(1.68954005899 + 0.570924387184*I, Vector space of degree 2 and dimension
0 over Complex Double Field
User basis matrix:
[]),
(-0.0345737707895 + 0.485480056628*I, Vector space of degree 2 and
dimension 0 over Complex Double Field
User basis matrix:
[])
]
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/4757>
Sage <http://sagemath.org/>
Sage - Open Source Mathematical Software: Building the Car Instead of
Reinventing the Wheel
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