[Numpy-discussion] Complex slicing and take
Eric Emsellem
eemselle at eso.org
Wed Dec 30 18:05:17 EST 2009
Thanks!
will try that and see how the performance varies depending on the size
of my arrays.
thanks again!
Eric
> Constructing big intermediate arrays, might not improve performance
> compared to a loop
>
>>>> >>> np.arange(30).reshape(6,5)
> array([[ 0, 1, 2, 3, 4],
> [ 5, 6, 7, 8, 9],
> [10, 11, 12, 13, 14],
> [15, 16, 17, 18, 19],
> [20, 21, 22, 23, 24],
> [25, 26, 27, 28, 29]])
>
>>>> >>> np.arange(30).reshape(6,5)[np.array([[1,2,2,1]]).T,np.arange(0,3)+np.array([[0,1,2,1]]).T]
> array([[ 5, 6, 7],
> [11, 12, 13],
> [12, 13, 14],
> [ 6, 7, 8]])
>
>>>> >>> np.arange(30).reshape(6,5)[np.array([[1,2,2,1]]).T,np.arange(0,3)+np.array([[0,1,2,1]]).T].sum(0)
> array([34, 38, 42])
>
> Josef
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