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

[Rob Beezer]

On 04/26/2011 11:25 AM, Pauli Virtanen wrote:
> I think it is worth testing if this change fixes it. Note that current
> LAPACK docs have the number 7 there instead of 5, so there may really be
> a bug here.

It appears to me the problem is more subtle than just a strict comparison 
between the number of rows and the number of columns.

http://trac.sagemath.org/sage_trac/attachment/ticket/11248/broken.png

shows a plot of matrix sizes (number of rows on the horizontal, number of 
columns on vertical).  This is on an OSX 10.5 machine and whereever there is a 
dot then the SVD seems to *always* produce a non-unitary V, and the absence of a 
dot indicates no failures were found.  So maybe a workspace size could be the 
culprit?