How can I fit a custom function that contains workspace vector variables?

6 views (last 30 days)
% data values
X = [-7.2460 -7.3355 -7.4320 -7.5752 -7.6996 -7.8780 -8.1560 -8.3517 -8.6170 -8.8883 -9.1808 -9.6629 -10.5808 -13.6249 -21.4783] ;
Y = [ -14.5516 -12.5218 -15.2762 -13.5768 -11.7304 -13.1678 -13.5329 -13.7761 -12.5162 -10.0737 -12.3137 -12.0351 -9.6663 -9.0393 -4.9973];
%fit
customfit = fit(X, Y, @(s, x) fun (s, X));
fittedfunc = fun(customfit.s, X);
figure;
plot(X, Y, 'r')
hold on
plot(X, fittedfunc, 'b')
function y = fun(s, x)
gme = 1.0e-04 *[0.0000 0.1978 0.2404 0.2862 0.2871 0.3603 0.4394 0.5141 0.5789 0.7762 0.7014 0.7476 0.8268 0.5400 0.0216];
y = log(((gme./x).^2))+log(s);
end
this is the code that does not work. I have to use that specific funcion with those specific values of "gme" and I'm interested in fitting it with those data and find the "s" parameter. Matlab's answer is:
Error using fit>iFit (line 127)
X must be a matrix with one or two columns.
Error in fit (line 108)
[fitobj, goodness, output, convmsg] = iFit( xdatain, ydatain, fittypeobj, ...
Error in Untitled (line 6)
customfit = fit(X, Y, @(s, x) fun (s, X));
Anybody knows how to solve this problem?? Thanks a lot!!

Answers (1)

darova
darova on 5 May 2020
Try following recommendations
  2 Comments
darova
darova on 5 May 2020
I changed your code
% data values
gme = 1.0e-04 *[0.0000 0.1978 0.2404 0.2862 0.2871 0.3603 0.4394 0.5141 0.5789 0.7762 0.7014 0.7476 0.8268 0.5400 0.0216];
X = [-7.2460 -7.3355 -7.4320 -7.5752 -7.6996 -7.8780 -8.1560 -8.3517 -8.6170 -8.8883 -9.1808 -9.6629 -10.5808 -13.6249 -21.4783] ;
Y = [ -14.5516 -12.5218 -15.2762 -13.5768 -11.7304 -13.1678 -13.5329 -13.7761 -12.5162 -10.0737 -12.3137 -12.0351 -9.6663 -9.0393 -4.9973];
gme = flip(gme);
X = flip(X);
Y = flip(Y);
f1 = griddedInterpolant(X,gme);
f2 = @(s,x) log(((f1(x)./x).^2))+log(s);
% F = fit(X(:), Y(:), f2);
plot(X, Y, 'r')
hold on
plot(X, f2(10,X), 'b')
hold off
Blue curve is the curve you want to fit
But only thing you are changing is s, it only moves the curve up and down. Are you sure your fit function is correct?

Sign in to comment.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by