Help! Input arguments for a called upon function not working!

Question

Spottswood 2016-10-2

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/305440-help-input-arguments-for-a-called-upon-function-not-working

评论： Walter Roberson 2016-10-5

I start with two two scripts, one with the function I'm trying to graph and get the value of x for a y, and the other that will help with fitting. The code for the two is here:

 f = fittype(@(a,b,c,d,e, x) real((a.*sqrt(1-(x./b).^2)+(a./2).* ...
    sqrt(1-(x./(2.*b)).^4)+c.*(e).^(-abs(x)./d) + e)));
 coeffs = coeffnames(f);
 pin = [-5,20,-275,50,20];
 [fitobject,gof] = fit(x,y,f,'StartPoint', pin);
 fitter(x,y,fitobject)

And the other is here:

if true
  % code
function [pout, yfit, res] = fitter(x,y,f, pin)
  % x - x data points vector
  % y - y data points vector
  % f - handle to function f(x,p) to be fitted, i.e. model
  % pin - function/model parameters initial guess vector 
  %
  % pout - parameters vector providing the best fit
  % yfit - y values calculated by the functions f(x,pout)
  % res - residuals (y-yfit)
  function yfit=yfitted(x,p)
    f_of_x=@(x) f(x,p);
    yfit=arrayfun(f_of_x,x);
  end
  function res=residuals(x,p)
    yfit = yfitted(x,p);
    res = y-yfit;
  end  
  % our merit function sum of residuals squared
  function E=chi_sq(p)
    res=residuals(x,p);
    E = sum( (res).^2 );
  end
% the main job of fitting 
  % (i.e.  optimization/best parameter finding)
  % is done by fminsearch
  pout=fminsearch(@chi_sq, pin); %fit is complete
  yfit=yfitted(x,pout);
  res=residuals(x,pout);
end
end

So now, the problem is that I when I run the first function, which calls upon the other one. It says there are not enough input arguments. But I can't figure out why because all the inputs are, well, inputted. The exact error occurs on line 30 of the function 'fitter' saying "pout=fminsearch(@chi_sq,pin); which causes an error when called upon in the fittype function.

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John D'Errico 2016-10-2

You are using the curve fitting toolbox, combined in some strange way with fminsearch? Is there a good reason why?

Spottswood 2016-10-2

It was written up by my professor and given to help fit this function with our data. This combination has worked before but I'm not sure why now it is saying input arguments. So to answer your question I am not sure why he is using the curve fitting toolbox combined with fminsearch

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Answer 1

Walter Roberson 2016-10-2

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/305440-help-input-arguments-for-a-called-upon-function-not-working#answer_236996

在 MATLAB Online 中打开

You are calling

fitter(x,y,fitobject)

but you define fitter() to require 4 input arguments, with the 4th of them being pin

6 个评论
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Spottswood 2016-10-4

So how do I fix this? I'm very lost and my teacher is of no use

Walter Roberson 2016-10-5

在 MATLAB Online 中打开

Get rid of most of that stuff. Replace it with

function pout = do_the_fit(x, y, pin)
  f = @(a,b,c,d,e) real((a .* sqrt(1-(x./b).^2) + (a./2) .* sqrt(1-(x./(2.*b)).^4) + c .* (e) .^ (-abs(x)./d) + e));
  resid = @(v) sum((f(v(1), v(2), v(3), v(4), v(5)).^2 - y).^2);
  pout = fminsearch(resid, pin);

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