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Nonlinear optimization problem near a local optimum http://forum.alglib.net/viewtopic.php?f=2&t=2509 
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Author:  johan [ Tue Jul 07, 2015 6:03 pm ] 
Post subject:  Nonlinear optimization problem near a local optimum 
Problem (this is not a "homework" problem but a "minimum working example" of the problem that I think I have. My problem can only be solved using leastsquareish approaches): Using f(x) = sin(x), find the solution for f(x) = 0 using the LevenbergMarquardt (LM) argorithm that is closest to x = 0.9 * (pi/2) as initial guess. Hence, a local optimum is searched for. The expected solution is x = 0. However, the alglib implementation of LM yields 18.85, which numerically represents 6 * pi. Further, assume that:
Questions:
<update>: The following can help to obtain the correct solution:
But what if bounds and/or step size information is not available? ==== Many thanks in advance! 
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