Not enough input arguments.

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Anonymous Chupacabra
评论： Anonymous Chupacabra 2015-4-27
I have a file called F.m which contains the following code:
1 % INPUT:
2 % 3D vector x
3 %
4 % OUTPUT:
5 % function value at x
6
7 function val = f(x)
8 val= x(1)^2 + x(1)*x(2)^3 - 12*x(3) + 4;
9 end
I am trying to call F.m in an algorithm in another file, but when I run the code, I get the following error:
"Error using F (line 8) Not enough input arguments."
I'm new to MATLAB, so I'm not sure what I'm doing wrong here. Any help would be greatly appreciated!
  2 个评论
Aaron Powers
Aaron Powers 2015-4-26
Could you include the code that calls your function f, with an example of what x is?
Anonymous Chupacabra
Anonymous Chupacabra 2015-4-26
Thank you for your interest in my question, Aaron!
x is a 3D point/vector, for example x = (x(1), x(2), x(3)) = (0,1,2).
Here's the code (it also calls on 2 other algorithms and requires input of other values too):
function [xminest, fminest,k] = Algorithm1(f, gradf, x0, tol1, tol2, T)
k = 0;
xk = x0;
while ( norm(feval(gradf, xk)) >= tol1 )
%du = feval(gradf, xk);
%dk = -du/norm(du);
dk = -1*feval(gradf, xk);
[a, b] = Algorithm2(f, xk, dk, T);
[tmin, fmin] = Algorithm3(f, a, b, tol2, xk, dk);
k = k + 1;
xk = xk + tmin*dk;
end
fminest = feval(f,xminest);
To run the code, I enter the command:
Algorithm1(F, gradf, [0,1,2], 0.1, 0.1, 10)

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采纳的回答

the cyclist
the cyclist 2015-4-26
With the syntax
Algorithm1(F, gradf, [0,1,2], 0.1, 0.1, 10)
MATLAB is looking for a variable named F (and similarly with gradf). You need to tell it that F is a function, by passing the function handle:
Algorithm1(@F, @gradf, [0,1,2], 0.1, 0.1, 10)
It looks like you have similar problems deeper in your code, but I could not resolve them completely because I don't have all the functions you are using.
  1 个评论
Anonymous Chupacabra
Anonymous Chupacabra 2015-4-27
Thank you very much, cyclist! After prefacing each file name with @ as you said, the code is executing as intended!

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更多回答（1 个）

Jan
Jan 2015-4-26
编辑：Jan 2015-4-26
Inside this line:
[a, b] = Algorithm2(f, xk, dk, T);
you call the function "f" without arguments. But You want top provide the function handle of this file instead:
[a, b] = Algorithm2(@f, xk, dk, T);
Note: In modern Matlab versions you can omit the feval and call the function handle directly, which looks nicer:
while norm(gradf(xk)) >= tol1
  1 个评论
Anonymous Chupacabra
Anonymous Chupacabra 2015-4-27
Thank you very much, Jan! Using the function handle as you showed worked! Thank you also for your tip, as I have the 2015 MATLAB version, but I think the algorithm code I am using may be quite old.

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