[Numpy-discussion] Zero row in SVD's unitary matrix on some Mac's

Pauli Virtanen pav at iki.fi
Tue Apr 26 16:29:40 EDT 2011


On Tue, 26 Apr 2011 14:52:52 -0500, Jason Grout wrote:
[clip]
> The updated rwork calculation makes no difference with a 3x4 matrix
> (both the old calculation and the new calculation give 66 in the 3x4
> case), so I don't think that is affecting anything.

Actually, there *is* a difference for the 3*4 matrix:

	old = 3*3*5 + 5*3 = 60
	new = 3*3*5 + 7*3 = 66

The old calculation had 5 instead of 7 in the formula --- I don't know if 
it was written according to an older version of the documentation, or if 
was is simply a bug.

	Pauli




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