change initial condition with binary data in matlab

clear all;
close all;
% Constants
M=315;                 % space domain length (in m)
c=2*pi;                % wvae speed constant (300 m/s = 2*pi rad/s)
dx=5.;                 % grid space interval
nx=round(M/dx)+1;      % number of grid in space domain
nk = nx-1;             % number of waves in frequency domain
dt = 0.001666;         % time step interval
nt=500;                % number of time steps
tmax = dt*nt;          % maximum time to calculate solution

% Initialization
u(:,1) = zeros(nx,1);
for ix=11:22
    xx=(ix-1)*dx;
    u(ix,1)=100*(sin(pi*((xx-50)/60)));
end
m = mean(u(:,1));    % k=0 contain the mean of the data, save it for latter

% Second initial condition
uk(:,1) = fft(u(:,1));           % Fourier Transform
uk(:,2) = complex(zeros(nx,1));  % get the Fourier coeff. for next step
for k = 1:nk,
     if (k < fix((nk/2))+1),
       uk(k+1,2) = (1 - dt*c*1i*(k))*uk(k+1,1);
     else
       uk(k+1,2) = (1 - dt*c*1i*(-nk-1+k))*uk(k+1,1);
     end  
end
ut = ifft(uk(:,2));    % Inverse Fourier to get u in space domain
u(:,2) = real(ut)+m;   % Add the average to the real part to get  u at second step
clear ut;              

% Solution using spectral method for all other t
uk(:,3:nt) = complex(zeros(nx,nt-2));  % get the Fourier coeff. for next step
for it = 3:nt,
  for k = 1:nk,
     if (k < fix((nk/2))+1),
       uk(k+1,it) = uk(k+1,it-2) - 2*dt*c*1i*(k)*uk(k+1,it-1);
     else
       uk(k+1,it) = uk(k+1,it-2) - 2*dt*c*1i*(-nk-1+k)*uk(k+1,it-1);
     end  
  end
  ut= ifft(uk(:,it));      % Inverse Fourier to get u in space domain
  u(:,it) = real(ut)+m;    % Add the average to the real part to get u at the next step
  clear ut;                
end

% Plotting output
xi =([1:nx])*dx;                     % x-axis
%x = [-pi+2*pi/nx:2*pi/nx:pi]';      % if wanted, x axis can be changed to -pi < x < pi
plot(xi,u(:,1),'-b','linewidth',2);  % Plot the initial condition
hold on;
for it=10:20:nt
    plot(xi,u(:,it),'-r');           % Plot the rest of the solution
end
hold off;
grid on;
axis([0 max(xi) -10 110]);
xlabel('X (m)','fontweight','bold');
ylabel('Amplitude','fontweight','bold');
title(['1D Linear Advection for t = ' num2str(tmax) ' seconds'],...
    'fontsize',14,'fontweight','bold');

Answer 1

[KALYAN ACHARJYA]

"change initial condition with binary data in matlab"

Is this?

Change here

u(:,1)=randi([0 1],nx,1)  

And

uk(:,2) =randi([0 1],nx,1)  

[iyya pangesti]

my teacher said that i have to add something like this :

%Read data

fid=fopen('file.dat','rb');

but i don't know where i can put it on my script. and which script that i have to edit.

i am beginner in matlab.

thank you anyway mr. Acharjya

[KALYAN ACHARJYA]

I answered based on initialization comment in the code. May be you have to load "u" data from that file.