Error while using a function instead of a .csv file

n = 5:40; %these are the limits of the function

c=2*n; %the function

a = (1-0.7)/(1-(0.7)^5);

w=a*(0.7).^[0:4];

for k = n

avg(k) = sum(fliplr(w)'.*c(k-4:k)); %this is the part where the error occurs

end

plot(n,c(5:40),':o');

hold on

plot(n,avg(5:40),'-x');

I get an error saying "Unable to perform assignment because the left and right sides have a different number of elements." when I run the code using the function (c=2*n) , but if I use a .csv file with the exact same values, instead of the function, the code works perfectly.

[Riccardo Scorretti]

I fixed some bugs in your code. What do you mean by "if I use a .cvs file"? Functions and .cvs files cannot be used in the same way. Perhaps you mean "when I import (which variable?) from a .cvs file"?

[Raed Mohamed Faiz]

Basically what I did was I used the data from the equation to produce a sheet in excel of the values ranging from the values of n=5 upto n=40, then imported this into matlab and used it to create the graph

Answer 1

[Riccardo Scorretti]

n = 5:40;   % these are the limits of the function

n runs from 5 to 40: you are bound to have problems when trying to evaluate c(n-4:n) because c is a vector of size 36. I guess the solution is to 0-pad the vector c:

c=[0 0 0 0 2*n];
% c=2*n;    % the function

a = (1-0.7)/(1-(0.7)^5); 
w=a*(0.7).^[0:4]; 

for k = n    

w' is a column vector (because w is a row vector) and c is a row vector, hence the product fliplr(w)'.*c(k-4:k) is a matrix, and the expression you want to evaluate is a row vector which contains the sum of columns of that matrix. Remove the trasposition:

    % avg(k) = sum(fliplr(w)'.*c(k-4:k)); % this is the part where the error occurs 
      avg(n) = sum(fliplr(w) .*c(n-4:n)); % this is the part where the error occurs 
end

plot(n,c(5:40),':o');
hold on
plot(n,avg(5:40),'-x');

[Raed Mohamed Faiz]

Unfortuantely the graph I am looking for would look something like this:

I did this using the .csv file method I mentioned earlier

n = 5:40;

c=csvread('QQQdata.csv') %the part where I use a csv file

a = (1-0.7)/(1-(0.7)^5);

w=a*(0.7).^[0:4];

for k = n

avg(k) = sum(fliplr(w)'.*c(k-4:k));

end

plot(n,c(5:40),':o');

hold on

plot(n,avg(5:40),'-x');

This is what the .csv file looked like

Thanks for the help though.

[Riccardo Scorretti]

Can you share the file .csv?

[Raed Mohamed Faiz]

Its alright, I got the answer to the question (c in this case was a column vector and not a row one like the .csv file), Thanks for the help though.