Input Argument Undefined for Passing a Parameter to a Function
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Hello,
I apologize if I am asking a very simple question but it's been something that I have been trying to work out and so far have been unsuccesful.
I am trying to write code to employ the gradient descent method on the camel function. Displayed below is the code:
Gradient Descent:
function [ dx ] = grad_d(v,f,gamma )
[Fx, Gx, Hx]= f(v);
dx = A - gamma*Gx;
end
In this case I want to use the function 'camel':
function [ Fx, Gx, Hx ] = camel(vec)
V = num2cell(vec);
[x,y] = V{:};
Fx = 2*x^2 - 1.05*x^4 + (x^6/6) + x*y+y^2;
Gx = [ x^5 - (21/5)*x^3 + 4*x + y;
x+2*y];
Hx = [ 5*x^4 - (63/5)*x^2 + 4, 1;
1, 2];
end
When I try to run one evaluation with the above code I get the error below:
I run the code as follows:
vec = ones(2,1)
grad_d(vec,camel,.1)
and receive the following:
_Input argument "vec" is undefined._
I know that I am overlooking something small but I can't pin it down. Any help would be much appreciated.
Thank you,
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Image Analyst
2015-2-16
0 个投票
Well you wrote the function to take in vec. What values do you want to pass in for it? You have to assign them. It can't read your mind.
3 个评论
Peter
2015-2-16
James Tursa
2015-2-16
编辑：James Tursa
2015-2-16
@Peter: Do you still have this line:
grad_d(vec,camel,.1)
The 2nd argument is camel. That will call the function camel without any input arguments to camel. Then when it gets inside the camel function and tries to use the variable vec, you get the error.
Image Analyst
2015-2-16
Don't pass in camel (If you did you'd have to use a @ in front of it).
vec = ones(2,1)
grad_d(vec,.1) % Call it without camel
Just call camel() inside the function:
function dx = grad_d(v,gamma)
[Fx, Gx, Hx]= camel(v);
dx = A - gamma*Gx;
end
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