why why why why why ..........................................

Question

Nasir Qazi 2012-2-27

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/30382-why-why-why-why-why

I have an code and when I try to run it, the status say busy , and it wont show me the answer to my solution , what exactly is the problem ?

[EDITDED, Jan Simon]: Copied from the comment section:

This program does not converge:

% Calculate Bubble Point and Dew Point SRK-EOS
% P = RT / V - b - alpha*a / V(V-b)
%----------------------------------------------
% liquid phase composition
y = [0.86 0.05 0.05 0.02 0.01 0.0095 0.0005]';
% vapor phase composition
x = [0.45 0.05 0.05 0.03 0.01 0.01 0.4]';
% critical pressure
Pc =[4.5947 4.8711 4.2472 3.6397 3.3688 3.1233 1.965]';
% critical temperature
Tc =[190.7389 305.5111 370.0333 425.3444 469.8889 512.7778 644.4444]';
% Accentric Factor
w = xlsread('myfile.xlsx','Sheet1','E2:E8');
%---------------------------------------------
L = 1;
R = 8.314e-3; % MPa m3 / mole.K
T = 200; % K
Tr = T./Tc; % K
P(L) = 5.0; %MPa
m = 0.480+1.574.*w -0.176.*w.^2;
al=1+ m.*(1-sqrt(Tr)).^2;
a = 0.42748.*(((R.*Tc).^2)./Pc);
b = 0.08664.*(R.*Tc./Pc);
q=0;
while q==0
  % Z3 - Z2 + (A-B-B^2)Z-AB=0
  % for gas phase
  SA = 0;
  RR = zeros(7,1);
  for i = 1:7
    for j = 1:7
      SA = SA + y(i).*y(j).*sqrt(a(i).*a(j).*al(i).*al(j));
      RR(i) = RR(i) + y(j).*sqrt(a(i).*a(j).*al(i).*al(j));
    end
  end
  SB = sum(y.*b);
  % For Liquid Phase
  SAA = 0;
  MM = zeros(7,1);
  for i = 1:7
    for j = 1:7
      SAA = SAA + x(i).*x(j)*sqrt(a(i).*a(j)*al(i).*al(j));
      MM(i) = MM(i) +x(j).*sqrt(a(i).*a(j).*al(i).*al(j));
    end
  end
  SBB = sum(x.*b);
  %for Gas Phase
  A = SA.*P(L)./(R*T).^2;
  B = SB.*P(L)./(R*T);
  ZV=roots([1 -1 A-B-B^2 -A*B]);
  Zv=max(ZV);
  Zvc=isreal(Zv);
  if Zvc == false
    Zv=abs(Zv);
    disp('error 1')
  end
  %for liquid Phase
  AA = (SAA.*P(L))./(R*T).^2;
  BB = (SBB.*P(L)./(R*T));
  Z=roots([1 -1 AA-BB-BB^2 -AA*BB]);
  Zl=min(Z);
  Zvl=isreal(Zl);
  if Zvl == false
    Zl=abs(Zl);
    disp('error 2')
  end
  phiv =exp((b.*(Zv-1)/SB) - log(Zv-B)-(A/B).*((2.*RR/SA)-
    (b/SB)).*log(1 + B/Zv));
  phil =exp((b.*(Zl-1)./SBB) - log(Zl-BB)-(AA./BB).*((2.*MM/SAA)-
    (b./SBB)).*log(1 + BB./Zl));
  K = phil./phiv;
  RA1= sum(y./K)-1;
  if abs(RA1) < 1e-5 && abs((y./K) - x) < 1e-5
    break
  else
    if L==1
      L = L+1;
      P(L) = 1.01.*P(L-1);
      RA1;
    else
      if L==1
        P(L)=P(L-1)-(RA1./(RA1-RA2))*(P(L-1)-P(L-2));
        RA2 = RA1;
      end
      %adjustment
      x2 = (1-0.5)*(y./K) + 0.5*x;
      x = x2;
    end
  end
end
disp(P(L));

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Jiro Doke 2012-2-27

Can you please rephrase the subject line so that it is specific to your question? Please read here:

http://www.mathworks.com/matlabcentral/about/answers/

and read the "Tips" under "Getting Started" -> "Ask a Question"

Walter Roberson 2012-2-27

Duplicate is at http://www.mathworks.com/matlabcentral/answers/30397-trial-and-error-help-is-not-giving-me-solution-to-that-still-waiting

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Answer 1

Grzegorz Knor 2012-2-27

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/30382-why-why-why-why-why#answer_38820

It means, that program is still running. Run it in debug mode, and you will see step by step how it works.

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Answer 2

Jan 2012-2-27

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/30382-why-why-why-why-why#answer_38824

You can insert a waitbar or some output in the code to be informed about the status of process. Either the computations take a lot of time or you have created an infinite loop by accident.

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Nasir Qazi 2012-2-27

% Calculate Bubble Point and Dew Point SRK-EOS

% P = RT / V - b - alpha*a / V(V-b)

%----------------------------------------------

% liquid phase composition

y = [0.86 0.05 0.05 0.02 0.01 0.0095 0.0005]';

% vapor phase composition

x = [0.45 0.05 0.05 0.03 0.01 0.01 0.4]';

% critical pressure

Pc =[4.5947 4.8711 4.2472 3.6397 3.3688 3.1233 1.965]';

% critical temperature

Tc =[190.7389 305.5111 370.0333 425.3444 469.8889 512.7778 644.4444]';

% Accentric Factor

w = xlsread('myfile.xlsx','Sheet1','E2:E8');

%---------------------------------------------

L = 1;

R = 8.314e-3; % MPa m3 / mole.K

T = 200; % K

Tr = T./Tc; % K

P(L) = 5.0; %MPa

m = 0.480+1.574.*w -0.176.*w.^2;

al=1+ m.*(1-sqrt(Tr)).^2;

a = 0.42748.*(((R.*Tc).^2)./Pc);

b = 0.08664.*(R.*Tc./Pc);

q=0;

while q==0

% Z3 - Z2 + (A-B-B^2)Z-AB=0

% for gas phase

SA = 0;

RR = zeros(7,1);

for i = 1:7

for j = 1:7

SA = SA + y(i).*y(j).*sqrt(a(i).*a(j).*al(i).*al(j));

RR(i) = RR(i) + y(j).*sqrt(a(i).*a(j).*al(i).*al(j));

end

SB = sum(y.*b);

% For Liquid Phase

SAA = 0;

MM = zeros(7,1);

for i = 1:7

for j = 1:7

SAA = SAA + x(i).*x(j)*sqrt(a(i).*a(j)*al(i).*al(j));

MM(i) = MM(i) +x(j).*sqrt(a(i).*a(j).*al(i).*al(j));

end

SBB = sum(x.*b);

%for Gas Phase

A = SA.*P(L)./(R*T).^2;

B = SB.*P(L)./(R*T);

ZV=roots([1 -1 A-B-B^2 -A*B]);

Zv=max(ZV);

Zvc=isreal(Zv);

if Zvc == false

Zv=abs(Zv);

disp('error 1')

end

%for liquid Phase

AA = (SAA.*P(L))./(R*T).^2;

BB = (SBB.*P(L)./(R*T));

Z=roots([1 -1 AA-BB-BB^2 -AA*BB]);

Zl=min(Z);

Zvl=isreal(Zl);

if Zvl == false

Zl=abs(Zl);

disp('error 2')

end

phiv =exp((b.*(Zv-1)/SB) - log(Zv-B)-(A/B).*((2.*RR/SA)-

(b/SB)).*log(1 + B/Zv));

phil =exp((b.*(Zl-1)./SBB) - log(Zl-BB)-(AA./BB).*((2.*MM/SAA)-

(b./SBB)).*log(1 + BB./Zl));

K = phil./phiv;

RA1= sum(y./K)-1;

if abs(RA1) < 1e-5 && abs((y./K) - x) < 1e-5

break

else

if L==1

L = L+1;

P(L) = 1.01.*P(L-1);

RA1;

else

if L==1

P(L)=P(L-1)-(RA1./(RA1-RA2))*(P(L-1)-P(L-2));

RA2 = RA1;

end

%adjustment

x2 = (1-0.5)*(y./K) + 0.5*x;

x = x2;

end

disp(P(L));

% I am trying to using trial and error to get the results of P(L) , but my solution is not converging and keep going on. I need to know what can I do to resolve the issue .

Help Please