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Re: File sizes and the SAVE command [message #48050 is a reply to message #48048]

Wed, 22 March 2006 03:58

Klaus Scipal
Messages: 45
Registered: November 1997

Member

The problem is not related to the calculation of the filesize, but the
actual amount of memory required

Take two arrays
a=intarr(100000)
b=fltarr(100000)

and save them using the save comannd
the file for array a takes 402096 bytes diskspace
the file for array b takes 402096 bytes diskspace

save them using openw & writeu
the file for array a takes 200000 bytes diskspace
the file for array b takes 400000 bytes diskspace

So the save command seems to waste a lot of diskspace, but why? Does the IDL
save command convert an integer automatically into a longinteger?

Klaus

"Maarten" <maarten.sneep@knmi.nl> wrote in message
news:1143025802.678782.180020@i39g2000cwa.googlegroups.com.. .
> I don't think you calculated quite what you thought you did.
>
> tmp = size(a) & tmp[1]*tmp[2]
> for a single dimensional array a will be the length of the array times
> the _type_ of the array, which has nothing to do with the actual
> byte-size of the elements.
>
> The save-sizes seem consistent though: 100000 * 4 bytes for float and
> int (long), double that for double precision floating point data.
>
> Maarten
>

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[Message index]

		Re: File sizes and the SAVE command By: Maarten[1] on Wed, 22 March 2006 07:27
		Re: File sizes and the SAVE command By: Klaus Scipal on Wed, 22 March 2006 07:17
		Re: File sizes and the SAVE command By: R.Bauer on Wed, 22 March 2006 05:26
		Re: File sizes and the SAVE command By: Klaus Scipal on Wed, 22 March 2006 03:58
		Re: File sizes and the SAVE command By: Maarten[1] on Wed, 22 March 2006 03:10
		Re: File sizes and the SAVE command By: Paolo Grigis on Wed, 22 March 2006 03:08

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