Function Error: Already declared

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Chase Weinberg
Chase Weinberg 2019-11-11
评论： Yasmeen 2023-7-19
My function was working fine until I typed in clear all. Now it does not work.
I get this error message: Function 'get_portfolio_return' has already been declared within this scope.
This is my function code:
function [E_Rp, sigma_Rp] = get_portfolio_return( weight,exp_rets, vols,corr)
E_Rp= weight.* exp_rets(1,1)+ (1-weight).*exp_rets(1,2);
sigma_Rp= sqrt((weight.^2.*vols(1).^2) + ((1-weight).^2.*vols(2).^2)+(2.*corr.*(weight)).*(1-weight).*vols(1).*vols(2));
end
% The stated function defines the necessary variables for subsequent
% calculations. Expected Return is calculated as a function of weight and
% expected returns. Weight is the weight of Asset1 and exp_rets are the
% expected returns of asset 1 and asset 2.
What caused this problem/ how do I fix it?
  1 个评论
Jeremy
Jeremy 2019-11-11
Did you save this as a function file separate from your main script file, or did you put it at the bottom of your script as a local function? Did you do both? How are you calling it?

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采纳的回答

Chase Weinberg
Chase Weinberg 2019-11-11
Okay, so the problem was the function name was different from what I assigned it. I did not realize the name I saved it as has to match the part after function []=
  1 个评论
Walter Roberson
Walter Roberson 2019-11-11
The rule is that if there is a difference between the file name and the name of the first function in the file, then in order to call the function, you need to use the file name.

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更多回答（2 个）

Muhammad Sinan
Muhammad Sinan 2019-12-30
When define user function in MATLAB programming then you will need the following format.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function (Dependent Variables1, 2, 3, ...) = FunctionName(Independent Variables1, 2, 3, ...)
body of function
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
so, when you save this file then you have to use this file on the name same as the name of the function. Otherwise, the function will not work.
Example:
FunctionName.m
  2 个评论
Sian Evans
Sian Evans 2020-6-5
My first function name and the file name are the same yet I still get this error? I don't understand how to bypass it?
Walter Roberson
Walter Roberson 2020-6-5
What is the first executable word in the file? The very first thing that is not a comment?

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Sumanth Hegde
Sumanth Hegde 2021-12-11
I got this error because I declared the same function name twice.

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