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

Alan G Isaac aisaac at american.edu
Fri Jun 23 11:03:13 CDT 2006


On Fri, 23 Jun 2006, Keith Goodman apparently wrote: 
> my x is a Nx1 matrix. I can't get it to work with matrices. 

Hmm. One would think that diag() would accept a flatiter 
object, but it does not.  Shouldn't it??

But anyway, you can squeeze x:

>>> x
matrix([[ 0.46474951],
       [ 0.0688041 ],
       [ 0.61141623]])
>>> y=N.diag(N.squeeze(x.A))
>>> y
array([[ 0.46474951,  0.        ,  0.        ],
       [ 0.        ,  0.0688041 ,  0.        ],
       [ 0.        ,  0.        ,  0.61141623]])

hth,
Alan Isaac







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