Help With Running while loop for a list

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Joe 2014-4-2

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https://ww2.mathworks.cn/matlabcentral/answers/124232-help-with-running-while-loop-for-a-list

评论： Joe 2014-4-2

I am able to run this doing it for a single value for P, but now i would like to do it for a range of values for P (i.e. a vector of 100 P values from 1 to 100), however I am getting an error and am not sure that I understand it.

Here is the code with the single P value problem

    function Z = RKZ(epsilon, Sigma, sigma, P, Pc, Tc, T, phi, xh, xl)
format long
Pr = P/Pc
Tr = T/Tc
x = xl + xh
beta = Sigma*(Pr/Tr)
q = phi/(Sigma*Tr^(1.5))
Y = @(X) 1 + beta - q*beta*((X-beta)/((X + epsilon*beta)*(X + sigma*beta))) - X
E = 0.0000000000001
Yx = Y(x)
while abs(Yx) > E
    x = (xl + xh)/2
    Yx = Y(x)
    if Y(x) > 0 
        xh = x
    else 
        xl = x 
    end 
    x 
end
Z = x 
end

And this is the code for the vector of P values (the one that I am having issues with):

      function Z = Zplot(epsilon, Sigma, sigma, p1, p2, Pc, T, Tc,  phi, xh, xl)
P = linspace(p1, p2, 100)
format long
Pr = P./Pc
Tr = T./Tc
i = 1:length(P)
x = ones(1,100)
beta = Sigma.*(Pr./Tr)
q = phi./(Sigma.*Tr.^(1.5))
Y = @(X) 1 + beta - q.*beta.*((X-beta)./((X + epsilon*beta).*(X + sigma*beta))) - X
E = 0.0000000000001
Yx = Y(x)
for i = 1:length(Yx)
while abs(Yx(i)) > E
    x(i) = (xl + xh)/2
    Yx(i) = Y(x(i))
    if Y(x(i)) > 0 
        xh = x(i)
    else 
        xl = x(i) 
    end 
    x (i)
end
Z = x
end
    end

I input these values:

Zplot(0, 0.08664, 1, 1, 100, 73.83, 304.2, 325, 0.42748, 0, 1)

and this was the error that I got:

     In an assignment  A(I) = B, the number of elements in B and I must be the same.
Error in Zplot (line 17)
    Yx(i) = Y(x(i))

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dpb 2014-4-2

...however I am getting an error and am not sure that I understand it.

Well, I'm sure we don't when you don't let us know what the error is. Cut 'n paste the whole error text in context w/ the code that used to call the function.

Joe 2014-4-2