how to identify the mistakes in loop in the given following code?

I have to find q, n value and TC. we need to find the these three values in iteration way. How to solve it?

clc
clear all
pr=7;
p=2500;
D=1600;
z=4;
zr=4;
m=10;
hr=5;
h1=12;
h2=11;
h3=13;
cL=4;
c=20;
c0=2;
c1=3;
c2=2;
ce=15;
k=0.1;
alpha=0.1;
beta=0.9;
u=1-alpha+alpha.*beta;
s=250;
A=110;
g0=15;
g1=20;
theta1=1;
theta2=0.6;
w0=0.3;
w1=0.2;
TC1=inf

TC1 = Inf

q=1:10:191

q = 1×20

1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191

n=1:1:20

n = 1×20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

j=1;
l=1;
for i=1:length(q)
    n=sqrt((D.*zr.*m+s+c.*g0+(A.*((q(i).*h2)/2))))/(q(i).*(((hr+cL.*k).*((D.*q(i))/(m.*p)))+((h1.*q(i)).*((1/2)-(((2.*u-1).*D)/(2.*p.*u))-D))+(D.*ce.*g1.*theta1)+(ce.*((w1.*(1-(((2.*u-1).*D)./(2.*D.*u))).*q(i))-(q(i)./2)).*theta2)));
    q=sqrt((2.*D.*(zr.*m+s+g0.*(c+n(i).*ce.*theta1)+A+n(i).*h3))./(n(i).^2.*(((hr+cL.*k).*(D./m.*p))+(h1.*(1-(((2.*u-1).*D)./(2.*p.*u)))+(ce.*(w1.*(2-(((2.*u-1).*D)./(p.*u))-1).*theta2))))));
    N(i+1)=n;
    Q(i+1)=q;
    j=j+1;
end

Index exceeds the number of array elements. Index must not exceed 1.

N
Q
z1=1;
for z=2:1:20
    if ((N(z)~=N(z-1)) | Q(z)~=Q(z-1))
        z1=z1+1;
    else
        break
    end
end
z1
j=1;
for i=1:20
    Q=Q(i);
    N=N(i);
    TC1=(pr.*D)+(z.*(m.*D./N(i).*Q(i)))+((hr+cL.*k).*(D.*N(i).*Q(i)./2.*m.*p))+(h1.*(1-(((2.*u-1).*D)./(2.*p.*u))).*N(i).*Q(i))-(h1.*N(i).*Q(i)/2)+(s.*D./N(i).*Q(i))+(D.*A./N(i).*Q(i))+(D.*h3./Q(i))+(D.*h2./2.*N(i))+((D./u).*(c0+(c1.*alpha)+(c0.*alpha)+(c2.*(1-beta).*alpha)))+((c.*D./N(i).*Q(i)).*(g0+g1.*N(i).*Q(i)))+(((D.*ce.*N(i).*theta1)./(N(i).*Q(i))).*(g0+g1.*N(i).*Q(i)))+((w0+w1.*(((1-(((2.*u-1).*D)./(2.*p.*u))).*N(i).*Q(i))-(N(i).*Q(i)/2))).*ce.*theta2);
    TC(i)=TC1;
    j=j+1;
end
round(TC)
for m=2:5
    if(TC1 >=TC)
        TC1=TC;
    else
        ansn = m+1;
        break
    end
end
round(TC)

[Ghazwan]

you have this line

n=1:1:20

Then, in the for loop, you are giving it new values.

[M.Rameswari Sudha]

I changed it. But i didnt get the answer

[Adam Danz]

Please edit your content and format your code. This will improve readability and will make it easy to copy blocks of code.

While in edit mode, use the Rich Text Editor tools to apply formatting.

[Jan]

@Adam Danz: Solved. I've explained formatting 1200 times and gave up finally. It is less work to format the code by my own.

[Adam Danz]

Thanks @Jan

@M.Rameswari Sudha, I ran your formatted code to reveal the error message.

[Jan]

@M.Rameswari Sudha: Codes like this must fail:

for i=1:20
    Q=Q(i);
    N=N(i);
    ...
end

In the first iteration the arrays Q and N are set to the scalar value of their first elements. Then there is no 2nd element in Q and N in the next iteration. The same problem here:

for i=1:length(q)
    n = sqrt((D.*zr.*m+s+c.*g0+(A.*((q(i) ...
    q = ... n(i) ...
    % Now q and n are scalars and in the 2nd iteration "q(i)" and "n(i)" will fail.
end

By the way, the code can be made much more readable. Comapre

j = 1;
for i=1:length(q)
    n=sqrt((D.*zr.*m+s+c.*g0+(A.*((q(i).*h2)/2))))/(q(i).*(((hr+cL.*k).*((D.*q(i))/(m.*p)))+((h1.*q(i)).*((1/2)-(((2.*u-1).*D)/(2.*p.*u))-D))+(D.*ce.*g1.*theta1)+(ce.*((w1.*(1-(((2.*u-1).*D)./(2.*D.*u))).*q(i))-(q(i)./2)).*theta2)));
    q=sqrt((2.*D.*(zr.*m+s+g0.*(c+n(i).*ce.*theta1)+A+n(i).*h3))./(n(i).^2.*(((hr+cL.*k).*(D./m.*p))+(h1.*(1-(((2.*u-1).*D)./(2.*p.*u)))+(ce.*(w1.*(2-(((2.*u-1).*D)./(p.*u))-1).*theta2))))));
    N(i+1)=n;
    Q(i+1)=q;
    j=j+1;
end

with

R = (2 * u - 1) * D;
S = R / (2 * p * u);

for i = 1:length(q)
    N(i+1) = sqrt(D * zr * m + s + c * g0 + A * q(i) * h2 / 2) / ...
        (q(i) * ((hr + cL * k) * D * q(i) / (m * p) + ...
        h1 * q(i) * (0.5 - S - D) + ...
        D * ce * g1 * theta1 + (ce * q(i) * (w1 * (1 - R / (2 * D * u)) - ...
        0.5) * theta2)));
    Q(i+1) = sqrt((2 * D * (zr * m + s + g0 * (c + n(i) * ce * theta1) + A + ...
        n(i) * h3)) / (n(i)^2 * ((hr + cL * k) * D / m * p + ...
        h1 * (1 - S) + (ce * w1 * (1 - 2 * S) * theta2))));
end
j = 1 + length(q);

Answer 1

[Adam Danz]

for i=1:length(q)
    n=sqrt((D.*zr.*m+s+c.*g0+(A.*((q(i).*h2)/2))))/(q(i).*(((hr+cL.*k).*((D.*q(i))/(m.*p)))+((h1.*q(i)).*((1/2)-(((2.*u-1).*D)/(2.*p.*u))-D))+(D.*ce.*g1.*theta1)+(ce.*((w1.*(1-(((2.*u-1).*D)./(2.*D.*u))).*q(i))-(q(i)./2)).*theta2)));
%                                  ^                ^ .... (and more)
    q=sqrt((2.*D.*(zr.*m+s+g0.*(c+n(i).*ce.*theta1)+A+n(i).*h3))./(n(i).^2.*(((hr+cL.*k).*(D./m.*p))+(h1.*(1-(((2.*u-1).*D)./(2.*p.*u)))+(ce.*(w1.*(2-(((2.*u-1).*D)./(p.*u))-1).*theta2))))));
%   ^ oops!     
    N(i+1)=n;
    Q(i+1)=q;
    j=j+1;
end

You're indexing q(i) assuming q is a vector which is the correct assumption on the first iteration of the loop. But then you're overwriting q and replacing the vector with a scalar. So when you index q(i) and i>1, you get an indexing error.