Why WHILE loop doesn't advance?

function cam()
clc
clear all
close all

N_i = input('N de intervalos:');

k=1;

while(k<=N_i)

      k

beta_i(k) = input('Beta do intervalo:');

L(k) = input('Lift do intervalo:');

mov(k) = input('Movimento do intervalo:');

k=k+1;

end

R_0 = input('Raio base:');

tb_i=0;
tb_f=1;

teta=0;

passo=1;
n=1;

T(n)=teta;

j=1;

while(j<=N_i)

      j

      switch mov(j)

          case 1

              while(teta<=beta_i(j))

              y=0.5*L(j)*(1-cos(pi*teta/beta_i(j)));
              dy=((pi*L(j))/(2*beta_i(j)))*sin(pi*teta/beta_i(j));

              u=(R_0+y)*sin(teta)+dy*cos(teta);
              v=(R_0+y)*cos(teta)-dy*sin(teta);

              T(n)=teta;

              A(n,:,j)=[y,dy,j]

              P(n,:,j)=[u,v,j]

              n=n+1;
              teta=teta+passo;

              end

          case 2

              while(teta<=beta_i(j))

              y=L(j)*((teta/beta_i(j))-sin(2*pi*(teta/beta_i(j))));
              dy=(L(j)/beta_i(j))*(1-cos(2*pi*(teta/beta_i(j))));

              u=(R_0+y)*sin(teta)+dy*cos(teta);
              v=(R_0+y)*cos(teta)-dy*sin(teta);

              T(n)=teta;

              A(n,:,j)=[y,dy,j]

              P(n,:,j)=[u,v,j]

              n=n+1;
              teta=teta+passo;

              end

      end

              j=j+1;
  end

end

Why the "while(j<=N_i)" loop only computes A and P for j=1 and doesn't advance after that? Can't understand...

[Adam]

Well, for a start we have no idea what N_i is since it is a user input.

[Miguel Viegas Leal]

Imagine N_i=2

[Miguel Viegas Leal]

For example when N_i=2 it only computes for j=1 but not for j=2 and I wonder why.

[Image Analyst]

Can you give typical numbers for all 5 user inputs, not just one, so we know what to enter and can try your code?

[Miguel Viegas Leal]

Try this:

N de intervalos:2

k =
     1

Beta do intervalo:180
Lift do intervalo:3
Movimento do intervalo:1

k =
     2

Beta do intervalo:90
Lift do intervalo:2
Movimento do intervalo:2
Raio base:0.025

Answer 1

[Walter Roberson]

I notice that you do not initialize teta between the two iterations of the while loop. Your while test is based upon teta which is going to continue to have the value it had after the first iteration of the loop, so the end condition might already be satisfied.

[Miguel Viegas Leal]

Thank you very much.

Answer 2

[Image Analyst]

It worked for me:

N de intervalos:2
k =
     1
Beta do intervalo:3
Lift do intervalo:3
Movimento do intervalo:4
k =
     2
Beta do intervalo:5
Lift do intervalo:6
Movimento do intervalo:7
Raio base:0
j =
     1
j =
     2

[Miguel Viegas Leal]

Try with this inputs instead:

N de intervalos:2
k =
     1
Beta do intervalo:180
Lift do intervalo:3
Movimento do intervalo:1
k =
     2
Beta do intervalo:90
Lift do intervalo:2
Movimento do intervalo:2
Raio base:0.025

[Image Analyst]

That also does both j. Look:

N de intervalos:2
k =
   1
Beta do intervalo:180
Lift do intervalo:3
Movimento do intervalo:1
k =
   2
Beta do intervalo:90
Lift do intervalo:2
Movimento do intervalo:2
Raio base:0.025
j =
   1
j =
   2

[Miguel Viegas Leal]

It doesn't compute vectors A and P for j=2...