Surface Plot for ODE solution

How can I make a surface plot for the ODE solution for different constants z?

w = 1; 
k=1;
figure
tspan = [0 5];
for z=0.1:0.01:0.5 

f = @(t,x) [-1i.*(2*w + 2*z).*x(1) + -1i.*sqrt(2).*k.*x(2);-1i.*sqrt(2).*k.*x(1) + -1i.*2*w*x(2)+-1i.*sqrt(2).*k.*x(3);-1i.*sqrt(2).*k.*x(2)+-1i.*2*w*x(3)];

[t,xa] = ode45(f,tspan,[0 1 0]);

gs = abs(xa).^2;

surf(t,z,gs(:,2))

end

[T K]

Please, when I run this code, this problem appears.

Error in Untitled7 (line 15)

surf(t,zv,gs2')

[Star Strider]

@T K — Check to see if you have a variable or user function called ‘surf’ by running this from a script or your Command Window —

which surf -all

/MATLAB/toolbox/matlab/graph3d/surf.m

It should give only this result. If it returns anything else, that points to the problem. The solution is to rename the other function or variable.

.

Answer 1

[Star Strider]

You need to make a few changes in your code:

w = 1; 
k=1;
figure
tspan = linspace(0, 5);                                 % Create Constant ‘tspan’
zv=0.1:0.01:0.5;                                        % Vector Of ‘z’ Values
gs2 = zeros(numel(tspan), numel(zv));                   % Preallocate
for k = 1:numel(zv)
    z = zv(k);
f = @(t,x) [-1i.*(2*w + 2*z).*x(1) + -1i.*sqrt(2).*k.*x(2);-1i.*sqrt(2).*k.*x(1) + -1i.*2*w*x(2)+-1i.*sqrt(2).*k.*x(3);-1i.*sqrt(2).*k.*x(2)+-1i.*2*w*x(3)];
[t,xa] = ode45(f,tspan,[0 1 0]);
gs = abs(xa).^2;
gs2(:,k) = gs(:,2);                                     % Save Second Column Of ‘gs’ In ‘gs2’ Matrix
end

figure
surf(t,zv,gs2')
grid on
xlabel('t')
ylabel('z')
shading('interp')

Experiment to get the result you want.

[Folke Voß]

Thank you a lot Star Strider.

The code is working the way I wanted to.

[Star Strider]

As always, my pleasure.