numpy-discussion

[Numpy-discussion] Sort , Complex array

[Nils W. <nw...@me...>]

Hi,

How can I sort an array of complex eigenvalues with respect to the
imaginary part
(in ascending order) in Numpy ?
All eigenvalues appear in complex cunjugate pairs.

Nils

Re: [Numpy-discussion] Sort , Complex array

[Konrad H. <hi...@cn...>]

Nils Wagner <nw...@me...> writes:

> How can I sort an array of complex eigenvalues with respect to the
> imaginary part
> (in ascending order) in Numpy ?
> All eigenvalues appear in complex cunjugate pairs.

indices = argsort(eigenvalues.imag)
eigenvalues = take(eigenvalues, indices)

Konrad.
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Re: [Numpy-discussion] Sort , Complex array

[Gerard V. <gve...@la...>]

On Monday 26 November 2001 11:53, Nils Wagner wrote:
> Hi,
>
> How can I sort an array of complex eigenvalues with respect to the
> imaginary part
> (in ascending order) in Numpy ?
> All eigenvalues appear in complex cunjugate pairs.
>
> Nils
>

I have solved that like this:
>>> from Numeric import *
>>> a = array([3+3j, 1+1j, 2+2j])
>>> b = a.imag
>>> print take(a, argsort(b))
[ 1.+1.j  2.+2.j  3.+3.j]
>>>

Best regards -- Gerard