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Re: Modifying an array while conserving memory [message #30874 is a reply to message #30872]

Thu, 23 May 2002 23:44

R.Bauer
Messages: 1424
Registered: November 1998

Senior Member

Randall Skelton wrote:
>
> Hi all,
>
> I have a large array and I would like to 'insert' some data into the
> middle of it. Imagine an array of 1000 points and having 100 points to
> insert beginning at index 500 (the resulting array will have 1100 points).
> Typically, I do not know the length of data I wish to insert until after
> 'a' is defined.
>
> a = findgen(1000)
> b = randomu(seed,100)
> c = fltarr(1100) ; seems wasteful to use more memory
> c[0:499] = a[0:499]
> c[500:599] = b
> c[600:1099] = a[500:999]
>
> In reality, 'a' is of order 2e7 so I would like to avoid making
> multiple copies of it. Does anyone have any suggestions regarding the
> most memory efficient way of doing this?
>
> Many thanks,
> Randall

Why not using pointer:

ptr1 = PTR_NEW(FINDGEN(1000))
insert = PTR_NEW(RANDOMU(seed,100))
a = PTR_NEW([(*ptr1)[0:499], (*insert), (*ptr1)[500:*]])

HELP,*a

regards
Reimar

--
Reimar Bauer

Institut fuer Stratosphaerische Chemie (ICG-I)
Forschungszentrum Juelich
email: R.Bauer@fz-juelich.de
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[Message index]

		Re: Modifying an array while conserving memory By: R.Bauer on Fri, 24 May 2002 02:49
		Re: Modifying an array while conserving memory By: Randall Skelton on Fri, 24 May 2002 02:06
		Re: Modifying an array while conserving memory By: R.Bauer on Thu, 23 May 2002 23:44
		Re: Modifying an array while conserving memory By: Craig Markwardt on Thu, 23 May 2002 20:03
		Re: Modifying an array while conserving memory By: David Fanning on Thu, 23 May 2002 19:58
		Re: Modifying an array while conserving memory By: Pavel A. Romashkin on Fri, 24 May 2002 09:33
		Re: Modifying an array while conserving memory By: Randall Skelton on Fri, 24 May 2002 04:45

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