Info
This question is closed. Reopen it to edit or answer.
Point out the error from this code
1 view (last 30 days)
Show older comments
kindly Point out the error from this code as I am getting this message "Subscript indices must either be real positive integers or logicals"
% Initialize Variables
startTime = -20-9;
endTime = 40-9;
n = startTime:endTime;
x = zeros(size(n));
% Define x
x(abs(n) == 5 ) = 1.5;
x(abs(n) == 4 ) = 3;
x(abs(n) == 3 ) = 1;
x(abs(n) == 2 ) = 0;
x(abs(n) == 1) = -0.5;
x(n == 0) = 2;
y = zeros(size(n));
for i = 1:length(n)
if i > 1 % for i=1 cannot look back in time , i.e. there is no x(0)
y(i) = 5*x(i) + 5/3.* x(i-2) -2*x(i-5)+1/2.*x(i+2)+1/2.*y(i-2)-1/4.*y(i-4);
else
y(i) = 5*x(i);
end
end % Compute y[n] here. Be sure to account for edge conditions. (See
% MATLAB Tutorial 2 Lecture code for an example)
disp([num2str(toc*1000) ' ms' ]); % display run time in ms on cmd line
figure;
subplot(2,1,1);
stem(n,x, 'k' );
ylim([0 1.5]);
xlabel('n' , 'fontsize' ,13)
ylabel('amplitude' , 'fontsize' ,12)
title('x[n]' , 'fontsize' ,13)
subplot(2,1,2);
stem(n,y, 'r' );
ylim([0 1.5]);
xlabel('n' , 'fontsize' ,13)
ylabel('amplitude' , 'fontsize' ,12)
title('y[n]' , 'fontsize' ,13)
1 Comment
Guillaume
on 12 Oct 2015
debug by forum is probably the least efficient way of debugging your code. You're better off using the tools provided by matlab.
In any case, the error message will also include a line number and the actual code that triggered the error. Please post this, rather than letting us guess.
Answers (2)
the cyclist
on 12 Oct 2015
Edited: the cyclist
on 12 Oct 2015
In this line
y(i) = 5*x(i) + 5/3.* x(i-2) -2*x(i-5)+1/2.*x(i+2)+1/2.*y(i-2)-1/4.*y(i-4);
you look back up to 5 time periods, so you are trying to access
y(-3)
when i = 2. That element obviously does not exist.
0 Comments
See Also
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!