
From:  Pierrick Hanlet 
Subject:  1/x fit 
Date:  Tue, 13 Mar 2018 17:19:01 +0000 
Useragent:  Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 
Hello
all, I'm using octave v4.0.3 on Fedora 25. I have some data, call it xraw and yraw which follows a 1/x curve. I'm attempting to minimize a function yrawyfit, so as to get the parameters 'p'. function y=fitcal(p) global xraw yraw; yfit=p(1)+1.0./(p(2)*xraw); y = sqrt(sum((yrawyfit).^2)); end I'm attempting to use fminsearch, such that my call to the function is: global xraw yraw; ... sx=[100,0.00015]; xraw=TXI; yraw=RXI; [sx,fxval]=fminsearch(@(sx)fitcal(sx),sx); Nothing that I try changes sx; i.e. the fitter always returns the initial values, so I'm assuming that my fit is failing. I've successfully done something like this before with trig function. So I'm wondering if my error is in the fact that I cannot set bounds on p(2); namely p(2)!=0.0. Is there something else that I'm missing? Else, is there something in Octave which mimicks Matlab fmincon? Thank you, Pierrick 

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