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Re: Reading Multiple DICOM Files [message #65544]

Tue, 10 March 2009 04:56

Foldy Lajos
Messages: 268
Registered: October 2001

Senior Member

On Mon, 9 Mar 2009, rtk wrote:

> On Mar 8, 6:17 pm, Jye <jye.sm...@gmail.com> wrote:
>> if i eq 0 then All_Images = image_slice else All_Images =
>> [[[All_Images]], [[image_slice]]]
>
> Forget too much Java, which, I agree, is a bad thing. I'd say you
> have been doing too much Matlab programming. The vast majority of
> your problem lies with the line above. If I run this code on my box:
>
> pro ttt0
> s = systime(1)
> for i=0,899 do begin
> im = fix(dist(256))
> if (i eq 0) then begin
> all = im
> endif else begin
> all = [[[all]], [[im]]]
> endelse
> endfor
> print, 'runtime = ', systime(1)-s
> help, all
> end
>
> It takes 93 seconds. However, if I run this code:
>
> pro ttt2
> all = intarr(256,256,900)
> s = systime(1)
> for i=0,899 do begin
> im = fix(dist(256))
> all[*,*,i] = im
> endfor
> print, 'runtime = ', systime(1)-s
> help, all
> end
>
> it takes 1.6 seconds. The only difference is that the output array is
> allocated once, instead of 900 times with 899 ever-increasing array
> copies to boot. Since you know the number of file in advance,
> allocate All_Images and just assign into it.
>
> Ron

You can get some more speedup by replacing 'all[*,*,i] = im' with
'all[0,0,i] = im':

; cut here, ttt2.pro
pro ttt2
all = intarr(256,256,900)
im = fix(dist(256))

s = systime(1)
for i=0,899 do begin
all[*,*,i] = im
endfor
print, 'runtime = ', systime(1)-s

s = systime(1)
for i=0,899 do begin
all[0,0,i] = im
endfor
print, 'runtime = ', systime(1)-s
end
; cut here

IDL> ttt2
% Compiled module: TTT2.
% Compiled module: DIST.
runtime = 0.20675302
runtime = 0.047688007

(This is not the bottleneck for the original problem, though.)

regards,
lajos

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[Message index]

		Re: Reading Multiple DICOM Files By: Foldy Lajos on Tue, 10 March 2009 04:56
		Re: Reading Multiple DICOM Files By: Jye on Mon, 09 March 2009 15:53
		Re: Reading Multiple DICOM Files By: rtk on Mon, 09 March 2009 11:07
		Re: Reading Multiple DICOM Files By: Robbie on Sun, 08 March 2009 20:11
		Re: Reading Multiple DICOM Files By: David Fanning on Sun, 08 March 2009 17:21
		Re: Reading Multiple DICOM Files By: Jye on Sun, 08 March 2009 17:17
		Re: Reading Multiple DICOM Files By: Robbie on Sun, 08 March 2009 16:42
		Re: Reading Multiple DICOM Files By: David Fanning on Sun, 08 March 2009 16:39
		Re: Reading Multiple DICOM Files By: Tibor47 on Mon, 23 March 2009 10:26

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