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

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?