why am i facing this error in plotting ?

a=1;
CFL = 0.8;
tf = 4/3;% tmax = 4/3;
N=50;
x = linspace(-1,1,N);% i took x = [-5;5]
dx = 2 /(N-1);
dt = (CFL * dx)/ abs(a);
lambda = (dt/dx);
t = [-4/3 : tf];

%Initial conditions:
 for i = 1: N
        if abs(x(i)) < 1/3  %McS, wrong abs(x(i) < 1/3 )
            u(i,1) = 1;
        elseif abs(x(i)) > 1/3 & abs(x(i)) <= 1
            u(i,1) = 0;
        end
 end

   plot(x,u(:,1),'k')

the error is :

Error using *plot*
vectors must be the same length
Error in 'burger' (line20)
plot(x,u(:,1),'k')

Answer 1

[Star Strider]

Your code runs for me without error in R2017b.

One possibility is that since ‘x’ is a row vector and ‘u’ is a column vector, transposing ‘x’ to a column vector could solve your problem:

plot(x', u, 'k')