How to get a value from inside a function?
2 views (last 30 days)
Show older comments
Ana Paula Pagnoncelli
on 6 Feb 2020
Answered: Bjorn Gustavsson
on 6 Feb 2020
I'm using the following function in my main program to calculate alpha_def:
alpha_def=fminbnd(@(alpha)fun_a(alpha, data_1, data_2, data_3, data_4, data_5, data_6), -alpha_0, alpha_0, options);
Inside of fun_a, I calculate beta_def the following way:
beta_def=lsqnonlin(@(beta)fun_b(beta, data_3, data_4, data_5, data_6), beta_0)
which is used to calculate alpha_def in fun_a.
After obtaining alpha_def, I need to use the value of beta_def in my main program. Is there a way of getting the value of beta_def from inside fun_a?
Thanks!
1 Comment
Bjorn Gustavsson
on 6 Feb 2020
No you dont. In your fminbnd call the anonymous function is independent of x and will just give an arbitrary result.
We might assume that you use:
alpha_def=fminbnd(@(x)fun_a(x, data_1, data_2, data_3, data_4, data_5, data_6), -alpha_0, alpha_0, options);
...but it might also be:
alpha_def=fminbnd(@(x)fun_a(alpha, data_1, data_2, data_3, data_4, x, data_6), -alpha_0, alpha_0, options);
Accepted Answer
Bjorn Gustavsson
on 6 Feb 2020
So we know something about your functions, but not much more than the most general stuff. If you write your function fun_a something like this:
function varargout = fun_a(alpha,data1,data2,data3,data4,data5,data6,beta_out_too)
beta_0 = alpha-data1; % or something
beta_def=lsqnonlin(@(beta)fun_b(beta, data_3, data_4, data_5, data_6), beta_0);
val = sum((beta_def*alpha-data1./data2).^2);
varargout{1} = val;
if beta_out_too
varargout{2} = beta_def;
end
end
Then you can change the call to fminbnd to:
alpha_def=fminbnd(@(alpha)fun_a(alpha, data_1, data_2, data_3, data_4, data_5, data_6,0), -alpha_0, alpha_0, options);
% Then call fun_a again to get the beta_def-value you're interested in:
[val,beta_optimal] = fun_a(alpha_def, data_1, data_2, data_3, data_4, data_5, data_6,1);'
HTH
0 Comments
More Answers (0)
See Also
Categories
Find more on Logical in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!