Need appropriate for loop with if condition

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GAGANDEEP KAUR
GAGANDEEP KAUR 2020-12-29
评论： VBBV 2020-12-30
I need to calculate V with some T value conditions, if T satisfies first condition I got to get desired values but if T lies in second or third condition, I am not able to represent the command appropriately. I will be grateful if I could get some correction. What I am trying to do is, say for second condition [elseif (423.85<T(j))&&(T(j)<=647.1)] for i=1, I made T values constant at 423.85, but for i=2 and i=3(here I means it should take up 2nd and 3rd valuesof Vc, Zc, Tc in loop as normal) I have written statements to be solved with given T(j). Similarly if third condition is true T is made constant, for i=1 T=423.85, for i=2, T=647.1 and for i=3 it should solve for given T(j)
function [V] = SolventMV(T,xm)
xm=[ 0.000006250 0.000006199 0.000004616;
0.4313 0.4315 0.4315;
0.2714 0.2681 0.2653];
T=[394.15; 399.15; 500.15 ];
Vc= [121.90 55.9 155];
Zc= [0.287 0.229 0.265];
Tc= [423.85 647.1 819.15];
N=length(T);
V=zeros(N,1);
vm=zeros(N,3);
v=zeros(N,3);
Tr=zeros(N,3);
for j=1:N
if (T(j)<=423.85)
for i=1:3
Tr(j,i)=T(j)/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(j,i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
V(j)=sum(v(j,:))/sum(xm(:,j));
end
elseif (423.85<T(j))&&(T(j)<=647.1)
for i=1
Tr(i)=423.85/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
for i=2:3
Tr(i)=T(j)/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
end
V(j)=sum(v(j,:))/sum(xm(:,j));
end
elseif (647.1<T(j))&&(T(j)<=819.15)
for i=1
Tr(i)=423.85/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
for i=2
Tr(i)=647.1/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
for i=3
Tr(i)=T/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
end
end
V(j)=sum(v(j,:))/sum(xm(:,j));
end
end
Tr
vm
v
V
end
end
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GAGANDEEP KAUR
GAGANDEEP KAUR 2020-12-30
It is showing invalid use of operator. Actually i think omitting loops might not work for me as I need to calculate V calculated with all the components 1,2,3, but on 1,2,3 conditions apply. As if, 3rd condition is true for i=1,T=Tc(1) ,constant,for i=2,T=Tc(2), constant and for i=3, T=T(j).
1 2 3
Vc= [121.90 55.9 155];
Zc= [0.287 0.229 0.265];
Tc= [423.85 647.1 819.15];
N=length(T);
V=zeros(N,1);
vm=zeros(N,3);
v=zeros(N,3);
Tr=zeros(N,3);
for j=1:N
if (T(j)<=423.85)
for i=1:3
Tr(j,i)=T(j)/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(j,i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
V(j)=sum(v(j,:))/sum(xm(:,j));
end
elseif (423.85<T(j))&&(T(j)<=647.1)
for i==1
Tr(i)=423.85/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
for i==2:3
Tr(i)=T(j)/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
end
V(j)=sum(v(j,:))/sum(xm(:,j));
end
elseif (647.1<T(j))&&(T(j)<=819.15)
for i==1
Tr(i)=423.85/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
for i==2
Tr(i)=647.1/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
for i==3
Tr(i)=T/Tc(i);
vm(j,i)=Vc(i)*(Zc(i)^((1-Tr(i))^0.286));
v(j,i)=xm(i,j)*vm(j,i);
end
end
V(j)=sum(v(j,:))/sum(xm(:,j));
end
end
Tr
vm
v
V
end
end
xm=[0.5096 0.5092 0.5087;
0.0963 0.0964 0.0965;
0.3941 0.3944 0.3948];
>> T=[394.15 399.15 404.15 ];[V]=SolventMV(T,xm)
Error: File: SolventMV.m Line: 29 Column: 14
Invalid use of operator.
VBBV
VBBV 2020-12-30
Note that the operator '==' is logical equivalent to equal for checking sameness. It can't be used in for loop iterative index as you have done in the program.
Look into the program structure in my earlier comment. It should work fine without errors.

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