[Numpy-discussion] How do I make a diagonal matrix?
Keith Goodman
kwgoodman at gmail.com
Fri Jun 23 09:55:47 CDT 2006
On 6/23/06, Sven Schreiber <svetosch at gmx.net> wrote:
> Keith Goodman schrieb:
> > How do I make a NxN diagonal matrix with a Nx1 column vector x along
> > the diagonal?
> >
>
> >>> help(n.diag)
> Help on function diag in module numpy.lib.twodim_base:
>
> diag(v, k=0)
> returns the k-th diagonal if v is a array or returns a array
> with v as the k-th diagonal if v is a vector.
I tried
>> x = rand(3,1)
>> diag(x)
array([ 0.87113114])
Isn't rand(3,1) a vector?
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.
Joris: The Numpy Example List looks good. I hadn't come across that before.
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