Using a loop in a loop Help pls..

Help... please a question about using loop inside a loop.

I got a loop which is

N=100;
i=1;
for x=0:c/N:c
    if x>=(P*c)
        dzdx(:,i)=(M*c/(1-P)^2)*(2*P/c-2*x/c^2);
    else
        dzdx(:,i)=(M*c/P^2)*(2*P/c-2*x/c^2);
    end
    i=i+1;
end
x=[0:c/N:c];
%%Using vortex_lattice to get gamma and xj
[gamma, xj] = vortex_lattice(dzdx, x, alpha, vinf, rhoinf, c);)

which i want to find gamma and , xj

I am sure the above code is correct , can i know how should i type if i want this loop run when N=[20:20:640]

following up from the gamma and xj

gamma_total=sum(gamma);
gamma_big=vinf*gamma_total;
% Finding Lift
L=rhoinf*vinf*gamma_big;
% Finding Coefficient of lift
C_lN(n)=L/(0.5*rhoinf*c*vinf^2);

How am I suppose to get 6 different C_lN when N[20,40,80,160,320,640]??

Answer 1

[John BG]

c=3e8;M=5;P=10  % since you did not define them I gave P and M these values

N=[20:20:640]

gamma_array=[]

xj_array=[]

big_dzdx=zeros(101,32) % 32 out of the 640/20 you want N to sweep through

for j=1:1:numel(N)

i=1;
for x=0:c/N:c
  if x>=(P*c)

        dzdx(:,i)=(M*c/(1-P)^2)*(2*P/c-2*x/c^2);
    else

        dzdx(:,i)=(M*c/P^2)*(2*P/c-2*x/c^2);
    end
    i=i+1;
  end
  x=[0:c/N:c];

big_dzdx(:,j)=dzdx

%%Using vortex_lattice to get gamma and xj

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

gamma_array(:,j)=[gamma_array; gamma]
xj_array=[xj_array; xj]

end