Recording solutions given by for loop as a vector.

So I have created a load of code that helps to plot the coefficient of lift across a 2D cambered wing. I have a bit of code that gives me a vector of numbers that directly impacts the coefficient. N = 20, 40, 80, 160, 320, 640. These N input values are run through a for loop showing how the output changes when the numbers double (20, 40, 80 etc.) The loop runs smoothly through all values, but I do not know how to record the values as a vector without upsetting the code already written. I will include the code below, bare in mind that it is a very experimental piece of code so there will be bits that look odd and such, ignore them, I simply need to know how to record the AREA output (one of the last lines of code inside the loop).

for N = [20,40,60,80,160,320,640];

GWE = (4.9736)./N;

x1 = [0:GWE:P*4];

x2 = [P*4:GWE:4];

x3 = cat(2,x1,x2);

x4 = [0:GWE:P*4];

x5 = [P*4:GWE:4];

x6 = cat(2,x4,x5);

Z1 = ((0.07*4)/(P.^2))*(((2*P)*(x4/4))-((x4/4).^2));

Z2 = ((0.07*4)/((1-P).^2))*((1-(2*P))+((2*P)*(x5/4))-((x5/4).^2));

Z3 = cat(2,Z1,Z2);

Y1 = (tmax/0.2)*((0.2969*((x3/c).^0.5))-(0.1281*(x3/4))-(0.3516*((x3/4).^2))+(0.2843*((x3/4).^3))-(0.1015*((x3/4).^4)));

dzdx = diff(Z3);

%To Stop The Loop From Not Syncing Together

TSTL = N - ((N*2)/10);

if TSTL > 127

    TSTL = N - (((N*2)/10)-1);

end

if TSTL >512

    TSTL = N - (((N*2)/10)-2);

end

x=x3(1,1:TSTL);

Y=Y1(1,1:TSTL);

Z=Z3(1,1:TSTL);

theta = atan(diff(Z3));

xup = x - (Y.*sin(theta));

yup = Z + (Y.*cos(theta));

xlow = x + (Y.*sin(theta));

ylow = Z - (Y.*cos(theta));

plot (x,Z, '-.r')

hold on

plot (x,0, 'g')

plot (xup,yup)

plot (xlow,ylow)

axis([-1 5 -1 1.5])

c = 4;

rhoinf = 1.2;

vinf = 80;

[gamma, xj] = vortex_lattice(dzdx, x, alpha, vinf, rhoinf, c);

figure

plot(xj, gamma);

Area = trapz(xj,gamma);

end

Answer 1

[Guillaume]

Replace the loop with:

NCoeffs =  [20,40,60,80,160,320,640];
Area = zeros(size(NCoeffs));
for coeffidx = 1:numel(NCoeffs)
   N = NCoeffs(coeffidx);
   ...

And the Area calculation with:

     Area(coeffidx) = trapz(xj, gamma);

[Joe]

This worked great. My answers are now being stored as a vector as required but unfortunately they are all using the first N value (20), I can't seem to get them to use the corresponding [20, 40,80,160 etc...]

[Guillaume]

The line

N = NCoeffs(coeffidx);

sets N to each of the values of NCoeffs. Did you forget the line?