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

Jason Grout jason-sage at creativetrax.com
Tue Apr 26 12:12:06 EDT 2011


On 4/26/11 11:07 AM, Jason Grout wrote:
> And indeed, I get a 0 row as the last row of the V**H matrix

I just double-checked things one last time and saw that I actually 
hadn't changed the first argument of zgesdd to "A" in the program that I 
actually ran.  So with this change, I get a nonzero last row of the V**H 
matrix from the C call to zgesdd.  So everything is consistent between 
the C call to zgesdd and the numpy svd call.

So now my remaining question is: if the Lapack docs only say that V**H 
is the full n-by-n matrix if M>=N, why is numpy returning it even if M<N?

Thanks,

Jason




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