[Numpy-discussion] How do I make a diagonal matrix?

Sven Schreiber svetosch at gmx.net
Fri Jun 23 11:07:32 EDT 2006

Keith Goodman schrieb:

> Isn't rand(3,1) a vector?

afaik not in numpy's terms, because two numbers are given for the
dimensions -- I also struggle with that, because I'm a matrix guy like
you ;-)

> Off list I was given the example:
>  x=rand(3)
> diag(3)
> That works. But my x is a Nx1 matrix. I can't get it to work with matrices.

ok, good point; with your x then diag(x.A[:,0]) should work, although
it's not very pretty. Maybe there are better ways, but I agree it would
be nice to be able to use matrices directly.


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