MATLAB: While loop doesn’t stop

while loop

Hey I've created the code described beneath but it doesn't run as planned. When I run it, the inner while loop 'while zonestop == 0' doesn't stop when it's condition isn't met anylonger? I can see that the condition is met in the command window.
Any help would be appreciated 🙂
%Debugging
clear clc %restarter alle kommandoer i Command window %alt køres ind med mm, N og MPa
% trinproces er 0,70 mm og stempeldiameteren er 110 mm
r = zeros(70,4); %preallocating = skrives for at lave hele matricen fra start, så det går hurtigere t = zeros(70,4); %; skrives for at matricen ikke skrives ud epsilontheta = zeros(70,4); epsilonn = zeros(70,4); epsilonr = zeros(70,4); den = zeros(70,4); det = zeros(70,4); der = zeros(70,4); epsilons = zeros(70,4); sigmas = zeros(70,4); sigman = 2*ones(70,4);%den første betingelse gør at sigman ikke må være 0 indledningsvis sigmar = zeros(70,4); k = zeros(70,4); l = zeros(70,4); A = zeros(70,1); F = zeros(29,1);
for i = 1:70 r0=110;%mm t0=1; %mm R=1.70; K=530; %N/mm^2 = MPa n=0.268; my=0.2;
    for j =1:4
        r(1,j)=r0-0.5*(j-1);
        r(i,1)=r0-1*(i-1);
    end
    %j = 1
    t(1,1)=t0;
    t(i,1)=t(1,1); 
    epsilonn(i,1)=0;
    epsilontheta(i,1)=0;
    epsilonr(i,1)=0;
    epsilons(i,1)=0;
    sigmas(i,1)=0;
    k(i,1)=0;
    l(i,1)=0;
    sigmar(i,1)=0;
    sigman(i,1)=0;
    F(i,1)=0;
end
    j=2;
    i = 1;
    done = 0;
    dt = 0;
    zonestop = 0;
while j <= 4
    while done == 0 %når denne løkke er færdig j=j+1        
        while zonestop == 0        
            if j ~= 1
                t(i,j)=t(i,j-1)+dt; %startantagelse af tykkelsen, dt ændrer sig            
                if i ~=70 %tykkelsen i hvert procestrin er ens
                    t(i+1,j)=t(i,j-1)+dt;
                    tic; r(i+1,j)=sqrt((2*((r(i,j))^2*(t(i,j)+t(i+1,j))/(2)-((r(i,1))^2-(r(i+1,1))^2)*t(i,1)))/(t(i,j)+t(i+1,j))); toc;
                end                        
            tic; epsilonn(i,j)=log(t(i,j)/t0); toc; 
            tic; epsilontheta(i,j)=log(r(i,j)/r(i,1)); toc;
            tic; epsilonr(i,j)= -(epsilonn(i,j) + epsilontheta(i,j)); toc;
            tic; den(i,j)=epsilonn(i,j) - epsilonn(i,j-1); toc;
            tic; det(i,j)=epsilontheta(i,j) - epsilontheta(i,j-1); toc;
            tic; der(i,j)=-(den(i,j)+det(i,j)); toc;
            tic; epsilons(i,j)=(sqrt(R+1))^2/(R+1)*sqrt(R*(der(i,j)-det(i,j))^2+(der(i,j)-R*den(i,j))^2+(det(i,j)-R*den(i,j))^2); toc;
            tic; sigmas(i,j)= K*(epsilons(i,j))^n;toc;
            tic; k(i,j)= sigmas(i,j)/epsilons(i,j)*((1+R)/(1+2*R))*(2*det(i,j)+den(i,j)); toc;
            %k=(sigmatheta(i,j)-sigmar(i,j))
            tic; l(i,j)= sigmas(i,j)/epsilons(i,j)*((1+R)/(1+2*R))*(den(i,j)*(1+R)+det(i,j)); toc; %den(i,j) = 0
            %l=(sigman(i,j)-sigmar(i,j))
                sigmar(1,j) = 0;           
                if i ~= 70 %for sigmar = 2:70
                    if j~=1 %er allerede defineret
                    tic; sigmar(i+1,j)=(sigmar(i,j)+(0.5*((k(i+1,j))/(r(i+1,j))+(30*k(i,j))/(r(i,j)))+(my)/(t(i,j))*((l(i+1,j))+sigman(i,j)))*(r(i+1,j)-r(i,j)))/(1-(my)/(t(i,j))*(r(i+1,j)-r(i,j))); toc;    
                    end
                end
            end
            if j == 1 % der er et loop inden i loopet
                sigman(i,1) = 0;
            else
                if i==1                    
                tic; sigman(1,j)= l(1,j); toc; %ved i=1 er sigmar = 0 
                else
                tic; sigman(i,j)=l(i,j)+sigmar(i,j); toc;
                end
            end
            if sigman >= 0
                zonestop = 1;
            else
                i = i+1;
                zonestop = 0;
            end
        end %while zonestop == 0
           i
        Fanvendt = 2.8*10^4; %N
        if i ~= 70 %50 radier, men 49 ringelementer
            F(i,1)= sigman(i,j)*((r(i,j))^2-(r(i+1,j))^2)*pi;
        end
        if sqrt((sum(F))^2)-Fanvendt > 0.01*Fanvendt %istedet for numerisk tegn
            dt = dt + 0.01;
            done = 0;
        else           
            done = 1;
        end
    end
    j=j+1;
end
t

Best Answer

The stopping test boils down to
if sigman >= 0
This only counts as true if all elements of the matrix sigman are greater than or equal to zero. If sigman has a negative element anywhere, the loop will continue. Is that what you want, or did you maybe mean
if sigman(i,j) >= 0
Related Question