An empty figure

Many thanks for getting back to me. I did the necessary changing by having another variable F with the same dimension of the one in the file, but when I tried to plot the figure from the code below, I received an empty figure. I should get a two 2 sin waves (blue and red) and a recovery one (the green). I think its the gradRO is taking only one value inside the loop {because I tried to print it in the command window) but I am not sure why this is happening. Would you kindly help me with this?

clear all T1 = 600; %ms T2 = 300; %ms df = 10; %for off-resonance

dT = 1; % delta time

flip =pi/3; % angle of RF pulse TE = 1; %ms

Gamma = 4256; %Hz/G

TR = 200; %ms.

%

[A,B] = freeprecess(dT,T1,T2,df);

 importfile ('allgradients.txt');

Gx = data(:,3);

F = length(Gx); %number of time steps

M = zeros(3,F);

M(:,1) = [0;0;1];

Rflip = yrot(flip);

M(:,2)=A*Rflip*M(:,1)+B;

for r=3:F

       M(:,r) = A*M(:,r)+B;    %propagation after RF pulse 

       gradRO = Gamma*pi*2*Gx(F-2)*(dT/1000)*2.9360;   
       M = zrot(gradRO)*M;

   end;

time = [1:F]*dT; plot(time,M(1,:),'b-',time,M(2,:),'r--',time,M(3,:),'g-.'); legend('M_x','M_y','M_z'); xlabel('Time (ms)'); ylabel('Magnetization'); axis([min(time) max(time) -1 1]); grid on;

[David Young]

This doesn't look like a new question - does it refer to a previous one? If so, please could you update the previous question by editing it, or adding comments as appropriate, as it's confusing to find new questions that are not self-contained.