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Re: Can i avoid the loop,help me speed up,thanks [message #61889 is a reply to message #61885]

Mon, 04 August 2008 14:31

Vince Hradil
Messages: 574
Registered: December 1999

Senior Member

On Aug 4, 3:44 pm, "ben.bighair" <ben.bigh...@gmail.com> wrote:
> On Aug 4, 9:29 am, Rongchang Chen <chenrc1...@gmail.com> wrote:
>
>
>
>> I wrote a procedure to create sinograms from projections in
>> tomography,the main part of procedure please see below.
>> For large size and number projections,it's very very slow.
>> Can i avoid the loop(one is OK) to speed up,or another way to create
>> sinograms?
>> Thank you very much!!
>
>> ************
>> n_sinogra:number of sinogram
>> n_projection:number of projection
>> files_projection:a string vector contain Directory and name of
>> projection
>> files_sino:a string vector contain Directory and name of sinogram
>
>> for jj = 0,n_sinogram-1 do begin
>> print,'now creating',jj+1,'th sinogram'
>> sino = fltarr(sizepro[0],n_projection)
>
>> for ii=0, n_projection-1 do begin
>> image = float(read_image(files_projection[ii]))
>> some processing of image
>> sino(*,ii) = image(*,jj)
>> endfor
>
>> write_tiff,files_sino(jj),sino,/short,/float
>> endfor
>> *****************
>
> Hi,
>
> I don't think it is possible for anyone to penetrate where you are
> having trouble with the given information. I think you might try
> using the builtin PROFILER routine for a start. It should reveal to
> you where you are spending most of your time.
>
> Unrelated to the speed issue, you seem to be specifying TIFF output
> simultaneously as a SHORT integer and a FLOAT. What type of image do
> you want to be saving?
>
> Cheers,
> Ben

I agree with Ben - the question is: what is in the "some processing of
image" step? If this can be "vectorized", then you might be able to
avoid some looping.

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[Message index]

		Re: Can i avoid the loop,help me speed up,thanks By: Jeremy Bailin on Tue, 05 August 2008 04:48
		Re: Can i avoid the loop,help me speed up,thanks By: Chris[6] on Mon, 04 August 2008 18:35
		Re: Can i avoid the loop,help me speed up,thanks By: Vince Hradil on Mon, 04 August 2008 14:31
		Re: Can i avoid the loop,help me speed up,thanks By: ben.bighair on Mon, 04 August 2008 13:44
		Re: Can i avoid the loop,help me speed up,thanks By: Rongchang Chen on Mon, 11 August 2008 07:56

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