Logical condition for a while lopp exits prematureley

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Philip Berg 2016-10-28

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评论： Jan 2016-10-28

Hi, I have this while loop criteria,

while((std(PenPar(:,2),0,1) > 50 && std(PenPar(:,3),0,1) > 50 && std(PenPar(:,4),0,1) > 50) || Stopper==500)

but it stops prematurely; only one of the and terms are satisfied.

Can someone explain me why it is so? Best reagrds

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KSSV 2016-10-28

As stopper is less then 500. This statement counts to 0. If any std out of three is not satisfied then loop will surely stops. You have to check your std.

Philip Berg 2016-10-28

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Ok, so my issue was that I don't want it to stop just because one of the std reaches bellow 50. Which I see, as I verbose the std constantly. Maybe if I specify my problem better. I want all statements to be true for it to stop. All three columns has to have a std bellow 50 for it to stop. Not just one of them. The last verbose is:

Running BigLoop itteration 1365 current st.dev =93.56746      124.6802      50.11569

so there is no way it is something with the std.

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Answer 1

Jan 2016-10-28

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while all(std(PenPar(:,2:4),0,1) > 50) || Stopper == 500

does, what you ask for. But this is equivalent to your code, because && has a higher precedence than || . Therefore I'm still convinced, that your code works fine and the loop is not finished too early. Are you sure that the loop is not terminated by the Stopper limit?

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Philip Berg 2016-10-28

编辑：Philip Berg 2016-10-28

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Yes, I have identified the problem here. I also baffles me why it wont work. Stopper gets an addition or reset in the following way:

    if PnewPenalty < fM
        NewAddition=[PnewPenalty Pnew];
        [~,RowIndex] = max(SumResiduals);
        PenPar(RowIndex,:) = NewAddition;
        disp('Replacing worst parameterset with:');
        disp('   r²          alpha           beta         k_i     ');
        dispParRes = [num2str(NewAddition(1,1)),'   ',num2str(NewAddition(1,2:end))];
        disp(dispParRes);
        Stopper=1;
    else
        Stopper=Stopper+1;
    end

And my last verbose before it finishes is as follows:

Running BigLoop itteration 1365 current st.dev =93.56746      124.6802      50.11569
Replacing worst parameter set with:
 r²          alpha           beta         k_i     
0.0012705   620.0898      827.0099      283.9735

Edit: which is printed with

    LoopMessage = ['Running BigLoop itteration ',num2str(ii), ' current st.dev =', num2str(std(PenPar(:,x+1:end)))];
    disp(LoopMessage);

edit2: x=1 in this case

Philip Berg 2016-10-28

Haha, thanks for the help! Indeed the error is in the verbose command. How tedious to not notice. Yes I did not expect magic from MATLAB.

Jan 2016-10-28

:-) Fine. I'm glad that your problem is solved. Have a nice day.

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Logical condition for a while lopp exits prematureley

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