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Re: Ordered index array [message #45431 is a reply to message #45430]

Thu, 08 September 2005 01:58

Emmanuel Christophe is currently offline

Emmanuel Christophe
Messages: 11
Registered: March 2004

Junior Member

Thanks Paolo,
Your function does exactly what I want, but my problem is precisely that
I need to do it on huge array (300 000 elements at least), that why i'm
looking for a more 'IDL' way to do it :)

Emmanuel

>
> But this will fail if 'a' has more elements than the number of
> its different values, for instance a=[3,3,1,2,3,2,2,1,2,3].
>
> One could try this:
>
> PRO test
>
> a=[3,3,1,2,3,2,2,1,2,3]
>
> b=a
> c=intarr(n_elements(a))
>
> h=histogram(a,min=1,reverse_ind=ri)
>
> done=0
> rank=1
> WHILE NOT done DO BEGIN
> actual_value=b[0]
> ind_actual_value=ri[ri[actual_value-1]:ri[actual_value]-1]
> c[ind_actual_value]=rank
> rank=rank+1
> indremove=where(b NE actual_value,count)
> IF count GT 0 THEN b=b[indremove] ELSE done=1
> ENDWHILE
>
> print,a
> print,c
>
> END
>
>
> but it will get inefficient as the numbers of different values
> in 'a' grows, as the code in the loop get called more and more
> times...
>
> Ciao,
> Paolo
>
>>
>> Cheers,
>>
>> David
>>
>>

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[Message index]

		Re: Ordered index array By: Emmanuel Christophe on Thu, 08 September 2005 07:51
		Re: Ordered index array By: David Fanning on Thu, 08 September 2005 06:55
		Re: Ordered index array By: Paolo Grigis on Thu, 08 September 2005 06:51
		Re: Ordered index array By: David Fanning on Thu, 08 September 2005 06:08
		Re: Ordered index array By: David Fanning on Thu, 08 September 2005 06:02
		Re: Ordered index array By: Paolo Grigis on Thu, 08 September 2005 05:30
		Re: Ordered index array By: Paolo Grigis on Thu, 08 September 2005 03:03
		Re: Ordered index array By: Emmanuel Christophe on Thu, 08 September 2005 01:58
		Re: Ordered index array By: Emmanuel Christophe on Thu, 08 September 2005 01:48
		Re: Ordered index array By: Paolo Grigis on Thu, 08 September 2005 01:22
		Re: Ordered index array By: David Fanning on Wed, 07 September 2005 10:17
		Re: Ordered index array By: David Fanning on Wed, 07 September 2005 10:01

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