I'm doing plate reduction on astro photos. There's non-linearity in the lens.  Basically, one is trying to estimate several lens parameters by look at a field of known stars versus ones measured on a photo plate. The author states it can be solved by taking first  derivatives to linearize matters, and iteratively apply least squares until the change in parameters falls below some limits. Gauss-Newton seems a bit different in that it tries to minimize the sum of squares.

In a follow up paper, he refers to  the process  as a gradient method.  Up until then, my best guess was G-N. I suspect that you are hinting at the Gradient plus LSQ (least squares).  However, out of curiosity, isn't their a library of optimization methods like Marquardt or Davidon?

On 5/28/2010 12:09 PM, Charles R Harris wrote:
What problem are you trying to solve. The leastsq algorithm in scipy is effectively Gauss-Newton when that is appropriate to the problem.

Chuck

On Fri, May 28, 2010 at 12:36 PM, Wayne Watson <sierra_mtnv...@sbcglobal.net> wrote:
Is Subject method available in Python?

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-- 
           Wayne Watson (Watson Adventures, Prop., Nevada City, CA)

             (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
              Obz Site:  39° 15' 7" N, 121° 2' 32" W, 2700 feet 

               There are no statues or memorials dedicated to  
               Thomas Paine for his substantial part in the
               American Revolution. 

                -- An observation in The Science of Liberty 
                      by Timoth Ferris
 
           
                    Web Page: <www.speckledwithstars.net/>
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