| help IDL with some equations implementation and optimized coding [message #71156] |
Mon, 31 May 2010 22:30 |
lila hadji
Messages: 7
Registered: June 2010
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Junior Member |
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Dear everybody,
I tried to implement the dictionary update step in the Method of
Optimal Directions, as explained in the paper (basically equations 8,
9, 17, 18 and 25)
% "Method of optimal directions for frame design",
% K. Engan, S. O. Aase, and J. H. Husøy,
% in Proc. ICASSP, Phoenix, AZ, Mar. 1999, pp. 2443Ð2446.
First link of the page:
http://scholar.google.com/scholar?hl=fr&q=%22Method+of+o ptimal+directions+for+frame+design%22&btnG=Rechercher&am p;lr=&as_ylo=&as_vis=0
The problem is that I didn't obtain good results - as it is expected
within the paper - with my implementation and I was wondering of
anyone can check out the code and the equations in the paper and help
me out why my code does not give the expected results and if there is
any improvements I can do on the code to get rid of the for-loop,
please?
Here is the version with the loop.
;;#IDL Code#
$Main$
;N=16 : size of each sample
;m=64: number of samples
;k=32:number of atoms in the dictionary to be learned
;Y=randomn(seed,m,n) : samples
;D=randomn(seed, k,n): dictionary to be learned
;X=randomn(seed,m,k): sparse codes to construct in the domain D
B=dblarr(N,k,/nozero)
ones=dblarr(N,/nozero)
ones(*)=1
A=invert(transpose(x)#X,/double)
R=Y-D##X
for i=0,k-1 do begin
xi=X(*,i)
B(*,i)=total((ones##xi)*R,1)
end
delta=A##B
D=D+transpose(delta)
end
;; #IDL Code#
Thank you very much for your help in advance.
Cheers
Lila
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