how to get the function as the sum of other functions?

Question

Oleksandr Oleksandras 2015-2-17

0
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https://ww2.mathworks.cn/matlabcentral/answers/178946-how-to-get-the-function-as-the-sum-of-other-functions

评论： Oleksandr Oleksandras 2015-3-2

I have a function fitfun=@(x)energy(i)-laa(i)*(1-exp(-x)), where x is unknown, energy and laa are arrays of values. I need to obtain expression for the summ of the functions: sumf=@(x)energy(1)-laa(1)*(1-exp(-x))+energy(2)-laa(2)*(1-exp(-x))...energy(N)-laa(N)*(1-exp(-x)). Next I need to minimize the "sumf" i.e. to find "x" which would give the value for total_function ~0. Fminsearch works perfectly for the individual function "fitfun" but not for the total sumf. Here is the script:

>

>syms x;
>> for i=1:N
function=@(x)energy(i)-laa(i)*(1-exp(-x))
sumf=@(x)sumf(x)+fitfun(x)
end
>> [x,fval] = fminsearch(sumf,[0])
Subscript indices must either be real positive integers or logicals.
Error in @(x)sumf(x)+fitfun(x)
Error in @(x)sumf(x)+fitfun(x)
Error in @(x)sumf(x)+fitfun(x)
Error in @(x)sumf(x)+fitfun(x)
Error in @(x)sumf(x)+fitfun(x)
Error in @(x)sumf(x)+fitfun(x)
Error in fminsearch (line 191)
fv(:,1) = funfcn(x,varargin{:});
>> 
Thank you