Re: More fun

[Martin Schultz <martin.schultz(at)dkrz.de>]

"J.D. Smith" wrote:
> 
> Here's one I just came up against.  Suppose you want to rebin a vector
> to some smaller size, an integer factor smaller.  E.g. 100 elements to
> 20 elements.  Now, rather than the average of those elements in each
> interval, etc., you want merely the average of the first and last member
> of that interval.  E.g., you want:
> 
> [(v[0]+v[4])/2, (v[5]+v[9])/2, (v[10]+v[14])/2, ...]
> 
> Rebin by itself can't work, I don't think.
> 
> Takers?
> 
> JD
> 
> P.S. No for loops please.  Bonus points if you don't build an explicit
> index list.
> 
> --
>  J.D. Smith                  |   WORK: (607) 255-6263
>  Cornell Dept. of Astronomy  |         (607) 255-5842
>  304 Space Sciences Bldg.    |    FAX: (607) 255-5875
>  Ithaca, NY 14853            |


Missing the bonus, I would suggest
nv=N_Elements(v)/5
res=0.5*( v[lindgen(nv)*5] + v[lindgen(nv)*5+4] )

But I am sure there is a way to do this with histogram ;-)

Cheers,
Martin

-- 
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