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Re: FIT across images [message #66008 is a reply to message #65891]

Wed, 08 April 2009 05:23

bas.basetta
Messages: 2
Registered: March 2009

Junior Member

Hi all,
just to let you know, I now figured it out.

I messed it up with

a. wrong dimensions of “F”, which has to be the same as “fit”
b. bad use of the * “simple” matrix product.

To simplify matrix products I reformed the S matrix as [n,size,size]
to [n,m], where m=size*size, and so A to [3,m]. I then used the
function

iv=replicate(1,(size(x,/dimensions))[0])
bx = EXP(-x#A[1,*])
F = (iv#A[0,*]) * bx + iv#A[2,*]

where x is now [n] and F is [n,m]. The procedure

fit=mpcurvefit(x,dummyS,W,A,sigma,function_name='expmap',chi sq=chisq,/
noderivative,/quiet)

now works, with fit=[n,m], and produces the same results as the double
forloop procedure does. The funny thing is: it is one hundred times
slower. Maybe there is a lesson to learn here.

Have fun,
Bas

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[Message index]

		FIT across images By: bas.basetta on Fri, 27 March 2009 08:28
		Re: FIT across images By: bas.basetta on Wed, 08 April 2009 05:23
		Re: FIT across images By: Craig Markwardt on Sun, 12 April 2009 16:38

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