錯誤使用==>函數fprintf不是爲「符號」輸入錯誤DISP（fprintf中（「...」）中定義的，請幫我

Question

% Condenser and hated fluid Data 
UAc = 30600 ; %W/K 
mc = 6.8 ;  %kg/s 

% Evaporator Data 
UAe = 26500 ; %W/K 
me = 7.6 ;  %kg/s 
%input data 
ta = input('Input Temperature at evaporator inlet water(celsius),ta : '); 
tb = input('Input Temperature at condensor inlet water(celsius),tb : '); 
cp = input('Specific heat capacity (kJ/kgK),cp : '); 
tol = 0.0001 %tol is converge tolerance 

%guess 
te= 5; 
tc= 45; 
qe= 160; 
qc= 190; 
P = 40; 
iter = 0 ; %iteration 
xnew = [te;tc;qe;qc;P]; 
xold = zeros(size(xnew)); 

while norm(xnew- xold) > tol 
    iter = iter+1; 
    xold = xnew ; 
    %update te,tc,qe,qc,P 
    te= xold(1); 
    tc= xold(2); 
    qe= xold(3); 
    qc= xold(4); 
    P = xold(5); 

    %Create equations for differrential; 

    %Refigeration capacity 
    f1 = sym('239.5+(10.073*te)-(0.109*(te^2))-(3.41*tc)-(0.0025*(tc^2))-(0.203*te*tc)+(0.0082*(te^2)*tc)+(0.0013*te*(tc^2))-(0.000080005*(te^2)*(tc^2))- qe'); 

    %Power required by compressor 
    f2 = sym('-2.634-(0.3081*te)-(0.00301*(te^2))+(1.066*tc)-(0.00528*(tc^2))-(0.0011*te*tc)-(0.000306*(te^2)*tc)+(0.000567*te*(tc^2))-(0.0000031*(te^2)*(tc^2))-P'); 

    %Evaporator heat transfer rate 
    f3 = sym('me*cp*(ta-te)*(1-exp(UAe/(me*cp*1000)))- qe'); 

    %Condensor heat transfer rate 
    f4 = sym('mc*cp*(tc-tb)*(1-exp(UAe/(mc*cp*1000)))- qc'); 

    %Energy balance 
    f5 = sym('P+qe-qc'); 

    % Newton raphson method 

    %diff f1 
    f1te = diff(f1,'te'); % differential f1 by te 
    f1tc = diff(f1,'tc'); % differential f1 by tc 
    f1qe = diff(f1,'qe'); % differential f1 by qe 
    f1qc = diff(f1,'qc'); % differential f1 by qc 
    f1P = diff(f1,'P'); % differential f1 by P 

    %diff f2 
    f2te = diff(f2,'te'); % differential f2 by te 
    f2tc = diff(f2,'tc'); % differential f2 by tc 
    f2qe = diff(f2,'qe'); % differential f2 by qe 
    f2qc = diff(f2,'qc'); % differential f2 by qc 
    f2P = diff(f2,'P'); % differential f2 by P 

    %diff f3 
    f3te = diff(f3,'te'); % differential f3 by te 
    f3tc = diff(f3,'tc'); % differential f3 by tc 
    f3qe = diff(f3,'qe'); % differential f3 by qe 
    f3qc = diff(f3,'qc'); % differential f3 by qc 
    f3P = diff(f3,'P'); % differential f3 by P 

    %diff f4 
    f4te = diff(f4,'te'); % differential f4 by te 
    f4tc = diff(f4,'tc'); % differential f4 by tc 
    f4qe = diff(f4,'qe'); % differential f4 by qe 
    f4qc = diff(f4,'qc'); % differential f4 by qc 
    f4P = diff(f4,'P'); % differential f4 by P 

    %diff f5 
    f5te = diff(f5,'te'); % differential f5 by te 
    f5tc = diff(f5,'tc'); % differential f5 by tc 
    f5qe = diff(f5,'qe'); % differential f5 by qe 
    f5qc = diff(f5,'qc'); % differential f5 by qc 
    f5P = diff(f5,'P'); % differential f5 by P 

    J = [f1te f1tc f1qe f1qc f1P;f2te f2tc f2qe f2qc f2P;f3te f3tc f3qe f3qc f3P;f4te f4tc f4qe f4qc f4P;f5te f5tc f5qe f5qc f5P]; 

    xnew = xold - J\[te;tc;qe;qc;P]; 
    disp(fprintf('iter=%6.5f, te=%6.5f, tc=%6.5f, qe=%6.5f, qc=%6.5f, P=%6.5f', iter,xnew)); 

end 

Answer 1

該錯誤消息似乎是清楚的。你爲什麼不只是顯示符號對象xnew無fprint：

disp(fprintf('iter=%6.5f, te=%6.5f, tc=%6.5f, qe=%6.5f, qc=%6.5f, P=%6.5f', iter)); 
disp(xnew) 

在另一方面根據您的代碼，我認爲應該xnew是數字載體，而不是象徵性的變量這是因爲你J雜物ble是象徵性的。我不知道你想完成什麼，因爲沒有給出任何描述或者甚至是一個問題，但是你可以試着用J代替（subs）得到一個數字向量。在符號表達式和數字數據中使用相同的變量名是不好的。 tc，tn ...

你不應該討厭液體。