fminsearch

12 次查看（过去 30 天）
Giuseppe
Giuseppe 2012-5-3
Hi, I need to find the best set of paramethers to minimize a chi-squared function. I wrote the function chi.m:
function chi = chi(theta, comp, sumcutmean);
model = theta * comp;
f = 0.0;
for i=1:1936
f = f + (sumcutmean(i) - model(i))^2;
end
chi = f;
end
where theta is 1x4 matrix of paramethers, comp is a 4x1936 matrix, of course model and sumcutmean are 1x1936. I tried to typing fminsearch in several ways, always obtaining errors. What is the correct expression to use?

请先登录，再回答此问题。

回答（3 个）

Taniadi
Taniadi 2012-5-3
i think that one of your errors is writing the function. the function should use different name for output variables.
Giuseppe
Giuseppe 2012-5-14
Thanks for the answer, but I'm not sure it was the problem. I modified the function:
function [chi] = f(theta, comp, sum1minus589cutmean);
model = theta * comp;
somma = 0.0;
for i=1:1935
somma = somma + (sum1minus589cutmean(i) - model(i))^2;
end
chi = somma;
end
Typing
>> [theta] = fminsearch(@(theta0) f(theta0, comp, sum1minus589cutmean), theta0);
I obtain:
Undefined function 'f' for input arguments of type 'double'.
Error in @(theta0)f(theta0,comp,sum1minus589cutmean)
Error in fminsearch (line 191) fv(:,1) = funfcn(x,varargin{:});
Taniadi
Taniadi 2012-5-15
I think that you can try to save your file using the filename "f.m" (equating your function name in function definition". And try to solve by using : theta = fminsearch(@f, guess,[],parameter). where parameter is list of parameters you try to include.
  1 个评论
Walter Roberson
Walter Roberson 2012-5-15
Adding the parameters at the end of the fminsearch() call is not documented as a possibility. Instead, using function handles and anonymous functions is recommended.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Oceanography and Hydrology 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by