How to Create Vector Function File

Question

Tom Keaton 2019-9-25

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/481990-how-to-create-vector-function-file

编辑： madhan ravi 2019-9-25

在 MATLAB Online 中打开

Hello,

I wish to create a vector function defined as the following:

The code I have so far:

function [Ex, Ey, Ez] = E_field()
syms x y z
con = -2.8E+8;
E = con*z.^3;
Ex = matlabFunction(E(1));
Ey = matlabFunction(E(2));
Ez = matlabFunction(E(3));
end

However, I get this error when this function is being referenced when Matlab's ode solver is running:

Index exceeds the number of array elements (1).
Error in sym/subsref (line 890)
            R_tilde = builtin('subsref',L_tilde,Idx);
Error in E_field (line 7)
Ey = matlabFunction(E(2));

I do not see why this wouldn't work as I have a very similar function file that is also being referenced but doesn't throw and error:

function [Bx, By, Bz] = B_test()
%Bfieldstrength = 0.64; %In (Teslas)
magvol = 3.218E-6; %In (m)
mu0 = (4*pi)*10^-7;
magnetization = (Bfieldstrength*magvol)/mu0;
syms x y z
m = [0,0,magnetization];
r = [x, y, z];
B = mu0*(((dot(m,r)*r*3)/norm(r)^5) - m/norm(r)^3);
Bx = matlabFunction(B(1));
By = matlabFunction(B(2));
Bz = matlabFunction(B(3));
end