MATLAB: Pol2cart in loop and pre-allocating

plo2cart pre allocating

hi all,
how can I put [x,y,z]=pol2cart(theta,rho,z), in tripple loop for different values of heta,rho,z, as well how to pre allocate [x,y,z]?
Regards

Best Answer

You need not preallocate (x,y,z) when you use the function.....If you want to run it thrice, you can do the following. 
X = cell(3,1) ; Y = cell(3,1);Z = cell(3,1) ;  
for i = 1:3
    [x,y,z]=pol2cart(theta{i},rho{i},z{i}) ; 
    X{i} = x ; Y{i} = y ; Z{i} = z ; 
end
If all the size of theta, rho, z are same. You can use matrices instead of cells. 
N = length(theta) ; 
X = zeros(N,3) ; Y = zeros(N,3); Z = zeros(N,3) ; 
for i = 1:3
    [x,y,z]=pol2cart(theta(:,i),rho(:,i),z(:,i)) ; 
    X(:,i) = x ; Y(:,i) = y ; Z(:,i) = z ; 
end
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