MATLAB: Error: Subscript indices must either be real positive integers or logicals.

Control System ToolboxindicesintegerslogicalsMATLABpositiverealsubscript

In code below, I get error "Subscript indices must either be real positive integers or logicals." when I run MAIN CODE from command line of customrlc(1,2,3). However, when I just run from command line this code:
%R=1;L=2e-3;C=3e-6;

G = tf([1/(L*C)],[1 R/L 1/(L*C)])
bode(G), grid
It works. I'm not sure what is causing the error, any thoughts? Thanks.
MAIN CODE
function customrlc(R,L,C)  
close all
%clear all
%clc
A = [0 1/C; -1/L -R/L]; 
B = [0; 1/L]; 
Cc = [1 -1]; 
D = [0]; 
%Create a Matlab state-space model.
sys = ss(A, B, Cc, D); 
close 'all';  
%Compute and plot the step response. 
%figure; 


[y, t] = step(sys); 
subplot(2,2,1)
plot(t, y); 
grid 
xlabel('Time (sec)'); 
ylabel('Amplitude ');
title('Step Response'); 
%Compute and plot the impulse response. 
%figure; 
[y, t] = impulse(sys); 
subplot(2,2,2) 
plot(t, y);
grid 
xlabel('Time (sec)'); 
ylabel('Amplitude ');
title('Impulse Response'); 
%Compute and plot the zero-state response to a sinusoidal input. 
%figure; 
dt = 0.002; 
tf = 4; 
t = 0 : dt : tf;
u = sin(t); 
[ysine, t] = lsim(sys, u, t);
subplot(2,2,3)
plot(t, ysine); 
grid 
xlabel('Time (sec)'); 
ylabel('Amplitude ');
title('Sine Response');
%bode response
hold on
figure
%R=1;L=2e-3;C=3e-6;
G = tf([1/(L*C)],[1 R/L 1/(L*C)])
bode(G), grid
end

Best Answer

I saw tf is mentioned twice
No, it's mentioned 3 times. Presumably you also changed the line
 tf=4;
to
 tff=4;
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