How to increment a subscript in Matlab using the ylabel function?

Hello,

I am trying to make my subscripts in my for loop interate with each loop. Below is a copy of my code. An example of how I would like the code to work is Figure(1) having the labels of x, for the x-axis, and PSI_1(x) for the y-axis. If anyone can help me in resolving this issue, it'll be greatly appreciated.

Very Respectfully,

Robert

CODE:

clc, clear, close all

L = 100; a = 0; b = L; N = L;

% Making a string of texts for Graph Titles 
s = ["First","Second","Third","Fourth"];  

for n=1:4                                   % 1st Four Energy States
syms x
psi = @(x) sqrt(2/L)*sin(n*pi*x/L);
ic = eval(subs(diff(psi,x,1),0));           % Inital Conditions
alpha = [0 ic];
[w, t] = rk4_system(@(t,ps)  analogous_pendulum(t,ps,n,L),a,b,N,alpha);

figure
hold on
fplot(psi,[0 100],'r','LineWidth',2)        % Plot Analytical Solution 
plot(t,w(1,:),'o b')                        % Plot of RK4
title(sprintf('%s Stationary State of the Infinite Square Well', s(n)))
ylabel('\psi_'+n+'(x)'), xlabel('x'),legend('Analytical', 'RK4')
end

[Robert Flores]

If this helps I am getting the following error.

Error using +

Matrix dimensions must agree.

Error in ME_500_HMWK3 (line 120)

ylabel('\psi_'+n+'(x)'), xlabel('x'),legend('Analytical', 'RK4')

Answer 1

[Rik]

The syntax you are attempting to use would work if you're using strings. However, you are using char arrays. Either switch to a string syntax, or use sprintf to create the annotation.

%option 1:
ylabel("\psi_"+n+"(x)"), xlabel('x'),legend('Analytical', 'RK4')

%option 2:
%double slash to escape the slash
ylabel(sprintf('\\psi_%d(x)',n)), xlabel('x'),legend('Analytical', 'RK4')