MATLAB Matlab for Loop of two changing variables

AI Thread Summary
The discussion revolves around a MATLAB coding issue where the user seeks assistance in calculating and storing values of a variable, sigmar, based on two nested loops. The outer loop iterates over values of r from 1 to 5, while the inner loop calculates sigmar for teta values ranging from 10 to 360 in increments of 10. The user emphasizes the need to store each sigmar value without overwriting previous calculations. Suggestions include using cell arrays or structures to retain the data. Additionally, the user expresses a desire to create a polar plot of the sigmar values against r, seeking guidance on how to implement this in MATLAB. A reference to a relevant Stack Overflow link is provided for further assistance.
adeeyo
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Hi,
Please I need your assistance on this MATLAB code. I will really appreciate it.

R=0.492; Pw=0.3708;

for r=1:5;

for teta=10:10:360;


sigmar=(1-(R.^2./r.^2))+(1-((4.*R.^2)./r.^2)+((3.*R.^4)./r.^4)).*cos(2.*teta)+(1-((4.*R.^2)./r.^2)+((3.*R.^4)./r.^4)).*sin(2.*teta)+Pw.*(R.^2./r.^2);


end

end

The only constraint is that for each time r changes, I want the loop to calculate value for sigmar with teta going form 10-360 with increament of 10 (teta=10:10:360).
To make it clearer, What I want is that, I want the code to take r=1, calculate 36 values for sigmar using teta=10:10:360, then take r=2, calculate 36 values for sigmar using teta=10:10:360, then take r=3, calculate 36 values for sigmar using teta=10:10:360, then take r=4, calculate 36 values for sigmar using teta=10:10:360, then take r=5,calculate 36 values for sigmar using teta=10:10:360.

Thanks for your usual assistance


Adeeyo
 
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Are you asking how to store the variables so that it doesn't get overwritten each time? If so, you could probably do that using cell arrays/structures/arrays

For example:
rndx = 1;

for r=1:5;
tetandx = 1;
for teta=10:10:360;


sigmar= ...
data(1,tetandx,rndx) = sigmar;

tetandx = tetandx + 1;
end
rndx = rnd + 1;
end
 
Hi Gringo,

Thanks for your quick response.
Yes. What I want is that I want calculated values of sigmar to be stored and not over-written at each value of r and teta=10:10:360.

Once again thanks

Adeeyo
 
Hi Gringo,

I want to make polar plot of the value of r and sigmar. polar(r,sigmar). Please how do I write the code so that I will have at each r (from r=1 to r=5) all the sigmar values corresponding to 36 teta values plotted in polar coordinate.

I am very grateful



Adeeyo
 
adeeyo said:
Hi Gringo,

I want to make polar plot of the value of r and sigmar. polar(r,sigmar). Please how do I write the code so that I will have at each r (from r=1 to r=5) all the sigmar values corresponding to 36 teta values plotted in polar coordinate.

I am very grateful



Adeeyo

Hey Adeeyo and welcome to the forums.

You should take a look at this for the general idea:

http://stackoverflow.com/questions/466972/array-of-matrices-in-matlab
 

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