Warning: Imaginary parts of complex X and/or Y arguments ignored.

I keep getting this error messgae when plotting some quantaties. My code points out that U_T is a cmplex double which is not true. So, I am not sure what is the problem, I know it happens in Line and in function C2P but I do not see how

gamma = 1.4;
sigmma = 1.0; 
CFL = 0.1; 
tend = 0.125; 
N_max = 10000; 
dx = 0.001; 
L = 1; 
x = 0:dx:L;
N = length(x);
rho1 = 1.0;
p1 = 1.0;
u1 = 0.0;
v1 = 0.0; 
w1 = 0.0; 
Bx1 = 0.0; 
By1 = 0.0; 
Bz1 = 0.0; 

rho5 = 0.125;
p5 = 0.1;
u5 = 0.0;
v5 = 0.0; 
w5 = 0.0; 
Bx5 = 0.0; 
By5 = 0.0; 
Bz5 = 0.0; 
VL = [rho1; u1; v1; w1; p1; Bx1; By1; Bz1]; 
VR = [rho5; u5; v5; w5; p5; Bx5; By5; Bz5];

I will attach my functions in case you wanna give it a run. But can someone help me understand the problem better. Thanks

[the cyclist]

I did try to run your code, but it errored at the line

[U_T, t] = MacCormack(U_T, gamma, t, dx, CFL, sigmma); % error here

Unrecognized function or variable 'MacCormack'

[Jamie Al]

Sorry, I just editted the post.

Answer 1

[Jamie Al]

Thanks, but I found the error was a negative sign in a rooted term that needed an abs function to solve it.