How do I ensure the loop is executed for the duration of the counts i.e. 10 inside the loop?

hi, i am having issues assigning variables inside the for loop for this simple filter. i want the filter loop to execute each equations inside the body over the duration of the loop (ie 10 counts for this filter)?

Thanks for your help!

% below is my code

a = 0.493;

b = 0.739;

g = 0.00234;

xi = 5;

vi = 1.5;

vok = 2;

gi = 1.3;

range = [r_raw]; % assume r_raw is [1 10] vector

for k = 1:1:length(r_raw)

xpk = xi + vi*dt + 0.5*(dt^2*gi);

vpk = vi + dt*gi;

apk = gi;

xsk = xpk + a*(range-xpk);

vsk = vpk + b*(vok-vpk);

ask = apk + g*(range-xpk)/dt^2;

xpred(k) = xsk;

% vpred(k) = vsk;

% apred(k)= ask;

end

figure; plot(xsk);

i get the following message:

Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.

[Yongjian Feng]

Which line gives the error above? What is dt in your code?

[abdul karim]

Time between two measurements.

Answer 1

[Sulaymon Eshkabilov]

There is an err in your code:

...
 xpred(k,:) = xsk;    % Corrected line
 ...

[abdul karim]

Thanks for taking the time to answer my question.

From what I understood, xpred(k,:) takes all the rows from the vector, correct?

It appears the value of variable k is 1 so its only counting or looping once inside the loop, is that correct? If so why? I want the k to iterate over the length of range so assume that's 10 for my example.

Thanks for your time.

[Sulaymon Eshkabilov]

Yes, it creates k number of rows of calc reults.

for k = 1:length(r_raw)    % defines how many rows of k for xpred(k,:) will be
 ...
     xpred(k,:) = xsk;    % Corrected line
 ...
end

[abdul karim]

How can I ensure the entire statements are repeated over the duration of the iterations within the body ie in this example 10 times? To be clear each I want the each statement (equation) to perform iterations over the entire duration, so k=1:1:length(r_raw) = 10? In hindsight, as more iterations are performed, the values should converge to the true value. Assume r_raw is an array of size (1,10) containing vectors.

I understand it may be simple but I can't think of what the issue is therefore help is really appreciated. Thanks again for your help.

I included the code again.

a = 0.493; b = 0.739; dt=0.001; t=(1:fr)*dt; xi = 0; vi = 1.5; vok = 2; range = [r_raw]; for k = 1:1:length(range ) xpk(k,:) = xi + vi*dt ; vpk(k,:) = vi; xsk(k,:) = xpk + a*(range-xpk); vsk(k,:) = vpk + b*(vok-vpk); xpk(:,k) = xi + vi*dt; vpk(:,k) = vi + dt*gi; xsk(:,k) = xpk + a*(range-xpk); vsk(:,k) = vpk + b*(vok-vpk); xpk(:,k)= xi + vi*dt; vpk (:,k)= vi + dt*gi xsk (:,k)= xpk + a*(range-xpk); vsk (:,k) = vpk + b*(vok-vpk); xpred(:,k) = xsk; end figure; plot(xsk);

Answer 2

[Sulaymon Eshkabilov]

In your code, there are a few crucial errs, i.e.:

(1) no need to introduce a new variable range that creates conflict with matlab's built in fcn range().

(2) why to use the same variable with different index orders: xpk(k,:) vs. xpk(:,k), xsk(k,:) vs. xsk(:,k), etc.

(3) range-xpk does not work because range has 10 elements and xpk has different number of elements. To avoid this problem, you should use: xpk=xi + vi*dt; xsk=r_raw(k)-xpk;

(4) If you want to get xpred only, there is no need to have indexes for other variables.

(5) fr and gi are not specified.