#12595: eigenmatrix of complex floating-point matrix is wrong
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Reporter: dkrenn | Owner: jason, was
Type: defect | Status: new
Priority: major | Milestone: sage-5.0
Component: linear algebra | Keywords: eigenmatrix, CDF
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
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{{{
sage: m = Matrix(CDF, 8, [[-1, -1, -1, -1, 1, -3, -1, -1], [1, 1, 1, 1,
-1, -1, 1, -3], [-1, 3, -1, -1, 1, 1, -1, -1], [-1, -1, -1, 3, 1, 1, -1,
-1], [1, 1, -3, 1, -1, -1, 1, 1], [1, 1, 1, 1, -1, -1, -3, 1], [3, -1, -1,
-1, 1, 1, -1, -1], [1, 1, 1, 1, 3, -1, 1, 1]])
sage: d, p = m.eigenmatrix_left()
sage: (p[1] * m)[0] / p[1][0]
1.2360679775 - 3.80422606518*I
sage: d[1][1]
1.2360679775 + 3.80422606518*I
}}}
Sage seems to return the complex conjugate of {{{d}}} or something of the
sort. Perhaps {{{d}}} is simply wrongly permuted (but real eigenvalues
seem to be correct).
{{{p.inverse() * d * p}}} should be at least approximately equal to
{{{m}}}.
This was reported on
[https://spreadsheets.google.com/pub?key=pCwvGVwSMxTzT6E2xNdo5fA the
public bug reports from the notebook interface] by <[email protected]>
on 1/24/2012.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12595>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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