[SciPy-user] why does linalg.sqrtm return an array?

Nils Wagner nwagner@iam.uni-stuttgart...
Thu Oct 9 13:30:40 CDT 2008


On Thu, 9 Oct 2008 14:26:50 -0400
  Brian Blais <bblais@bryant.edu> wrote:
> Hello,
> 
> I was just bitten by the fact that sqrtm returns an 
>array, not a  matrix.  Every time I tried to test it with 
>Q*Q, or Q.T*Q I got very  strange results (I was just 
>about to post that it was seriously  broken).  Then I 
>found out that it returns an array!  Why is that?   It 
>would seem that if you are doing a matrix square root, 
>you are  working with matrices mostly in that 
>calculation, so a matrix is the  consistent thing to 
>return (and perhaps the least surprising thing to 
> return).  Is there a reason for this?
> 
> 
> 		thanks,
> 
> 			Brian Blais
> 
> -- 
> Brian Blais
> bblais@bryant.edu
> http://web.bryant.edu/~bblais
> 
> 
> 
This is a known problem.
See
http://projects.scipy.org/scipy/scipy/ticket/585

Nils


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