MATLAB: How to speed up the while loops

MATLABoptimizationr2014aspeedwhile loop

Hello,
I have been looking for ways to speed up my code because sometimes I spend some hours at running once MATLAB. I've read: http://blogs.mathworks.com/loren/2008/06/25/speeding-up-matlab-applications/ But it's all about "for" loops (spectacular post, BTW). The problem is that I mainly have "while" loops so I don't get how could I vectorize them. The main problem is that I call another function I've made inside my "while" loop, and that function has another "while" which calls another function with another "while".
I would appreciate any tip. Here you have part of one of my functions, if you want an example:
PSspan = [t0 t0+increment];
[resu] = nInt(ab,PSspan,hmax,tol);    
[resu] = ham(resu);    
[resuPol] = convPol(resu);
while iPS<nPS && loop<loopLimit
      loop=loop+1; if mod(loop,250)==0; display(loop); end
      ab=resu(2:5,end);
      t0=resu(1,end);  PSspan=[t0 t0+increment];
      [resu] = nInt(ab,PSspan,hmax,tol);    
      [resu] = ham(resu);    
      [resuPol] = convPol(resu);
      %Comprovació de si s'ha arribat a PS per thetaP
      switch   tipusCoord
          case 'Cartesianes'; 
              p=resu(variablePS,1);     
              q=resu(variablePS,end);
             ctrl=resu(vControl,1);
         case 'Polars';      
             p=resuPol(variablePS,1);  
             q=resuPol(variablePS,end);  
             ctrl=resuPol(vControl,1);
      end
      if p*q<0 && ctrl>0
          %Poincaré section
          iPS=iPS+1; display(iPS);  loop=0;
          [ coordCart, coordPol ] = BiseccioMod( resu , hmax, tipusCoord, variablePS );
          resuPS(:,iPS)=coordCart;  resuPSPol(:,iPS)=coordPol;
      end
end

Best Answer

Why do you assume, that the while loop needs a remarkable amount of time in your code? The profiler will reveal, which lines or subfunctions require the most time. When the loop itself takes a few percent of the processing time only, an optimization is not efficient.
Matlab's JIT acceleration is impeded, if lines contain more than one command. Therefore and to improve the readability, use one command per line only.
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