id	summary	reporter	owner	description	type	status	priority	milestone	component	resolution	keywords	cc	work_issues	upstream	reviewer	author	merged	dependencies	stopgaps
10795	Fix and upgrade double dense matrix QR decomposition	rbeezer	jason, was	"The Q matrix of a QR decomposition should be unitary, hence invertible.  For zero-column trivial cases, this is broken.

{{{
sage: A = zero_matrix(CDF, 5, 0)
sage: Q, R = A.QR()
sage: Q
[0 0 0 0 0]
[0 0 0 0 0]
[0 0 0 0 0]
[0 0 0 0 0]
[0 0 0 0 0]
}}}

Besides a bugfix this patch will upgrade the documentation to make it clear how this routine works over the complex numbers.  In particular, `SciPy` routines are using a Hermitian inner product - documentation upgrade will reflect that.

'''Apply''':
  1.  [attachment:trac_10795-QR-decomposition-double-dense-v2.patch]
  1.  [attachment:trac_10795-QR-decomposition-formatting.patch]"	defect	closed	minor	sage-5.2	linear algebra	fixed	sd40.5	jason ddrake		N/A	Martin Raum, Dan Drake	Rob Beezer	sage-5.2.beta1