error in using a function while using surf plot

I am trying to plot a 3D plot using surf function im MATLAB.

I am using a calc fucntion and it gives an error "Z must be a matrix and not a scalar value".

Please help me resolve this error.

function fx = calc(x, const)
    A = const(1);
    B = const(2);

    r = sqrt(x(1)^2 + x(2)^2);
    fx = A * cos(r)^2 * exp(-B * r);
end

% Constants
A = 2;
B = 0.3;

% Coordinates
x = [3; 2];

% Evaluate the function at the given point
fx = calc(x, [A, B]);

% Define the range of x and y values
x_range = linspace(-10, 10, 100);
y_range = linspace(-10, 10, 100);

% Create a grid of points
[X, Y] = meshgrid(x_range, y_range);

% Evaluate the function at each point of the grid
Z = calc([X(:) Y(:)]', [A, B]);

surf(X,Y,Z)

Answer 1

[Ronit]

The input in calc function is taking a matrix input which is creating this error. Instead of using x(1) and x(2), try using x(1,:) and x(2,:).

Since you are using an array and not a scalar value, you should use .^, .* and ./instead of ^,* and /.

Instead of sending an array input, I suggest you to input x, y separately

function fx = calc(x, y, const)
    A = const(1);
    B = const(2);

    r = sqrt(X.^2 + Y.^2);
    fx = A * cos(r).^2 .* exp(-B * r);
end

Then call the function:

Z = calc(x, y, [A, B]);
surf(X,Y,Z)