Error with using fminsearch

I want to convert a "function" with symbolic variables into an actual matlabfunction and search the minimum by using fminsearch. But I am getting an error saying that I havent got enough input arguments.

syms x y;

% Peaks Funktion

f = 3*(1-x)^2 * exp(-x^2-(y+1)^2)-10*(x/5-x^3-y^5)*exp(-x^2-y^2)-(exp(-(x+1)^2-y^2)/3);

f1 = matlabFunction(f);
gradient1 = gradient(f);

x0 = [4,3];
minimum = fminsearch(f1,x0);

I also tried

fminsearch(@(x,y) f1(x,y), x0);

but the error stays the same.

Does someone know what Im doing wrong?

Answer 1

[Star Strider]

Yoiu need to add the 'Vars' argument to your matlabFunction call—

syms x y;

% Peaks Funktion

f = 3*(1-x)^2 * exp(-x^2-(y+1)^2)-10*(x/5-x^3-y^5)*exp(-x^2-y^2)-(exp(-(x+1)^2-y^2)/3);

% f1 = matlabFunction(f)
f1 = matlabFunction(f, 'Vars',{[x,y]})                              % Creates Parameter Vector 'In1' Containing 'x' As 'In1(:,1)' And 'y' As 'In1(:,2)'

f1 = function_handle with value:
    @(in1)exp(-(in1(:,1)+1.0).^2-in1(:,2).^2).*(-1.0./3.0)+exp(-(in1(:,2)+1.0).^2-in1(:,1).^2).*(in1(:,1)-1.0).^2.*3.0+exp(-in1(:,1).^2-in1(:,2).^2).*(in1(:,1).*-2.0+in1(:,1).^3.*1.0e+1+in1(:,2).^5.*1.0e+1)

gradient1 = gradient(f);

x0 = [4,3];
[minimum, fval] = fminsearch(f1,x0)

minimum = 1×2

27.1695 6.5127

fval = 0

Alternatively, you could create a separate funciton using the initial matlabFunction result as:

f1 = @(b) f(b(1),b(2));

however letting matlabFunction take care of those details is just easier.

EDIT — (21 Jan 2024 at 18:35)

Minor correction to add clarity. Code unchanged.

.

[Daniel]

Thank you!

[Star Strider]

My pleasure!

If my Answer helped you solve your problem, please Accept it!

.