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Re: intarr speed in structure [message #10847]

Mon, 16 February 1998 00:00

Kevin Ivory
Messages: 71
Registered: January 1997

Member

c.c.mclean@ed.ac.uk wrote:
> When I allocate an array, as part of a structure, it
> takes far longer to perform the operation than normal.
>
> a) array=intarr(x,y,z)
> b) array={volume:intarr(x,y,z)}
>
> if I use x=2048,y=240,z=5 a) takes 0.1s, b) takes 0.4s
> if I use x=2048,y=240,z=15 a) takes 0.4s,b) takes 2mins
>
> The same thing happens with IDL 5.03 under win95 (P200, 32MB)
> and with IDL 4 on an HP workstation.

Just some wild guessing:
It looks like b) is making the array first, then the structure.
For the first example that would make 10 MB for a), 20 MB for b),
for the second example 30 MB for a), 60 MB for b)
Since you only have 32 MB RAM, IDL starts swapping to disk,
which is very slow.

For b) you might want to try: array={volume:intarr(x,y,z, /nozero)}
I didn't test it, but it might help.

Best regards
Kevin
--
Kevin Ivory Tel: +49 5556 979 434
Max-Planck-Institut fuer Aeronomie Fax: +49 5556 979 240
Max-Planck-Str. 2 mailto:Kevin.Ivory@linmpi.mpg.de
D-37191 Katlenburg-Lindau, GERMANY http://www.gwdg.de/~kivory2/

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		Re: intarr speed in structure By: Kevin Ivory on Mon, 16 February 1998 00:00
		Re: intarr speed in structure By: Dr. G. Scott Lett on Mon, 16 February 1998 00:00

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