program going beyond matrix dimension

    %first electric field envelop in fourier space
    tic;
    clc
    clear all
    close all
    Po=9;

    Ao=sqrt(Po);
    C=0;
    %pi=3.1415926535;
    x=-60*10^-15:1*10^-15:59*10^-15;

    x = 10*x;
    i=sqrt(-1);
    Wo=120*10^-15;%initial pulse width in second
    u=Ao*exp(-(x./Wo).^2)
    figure(1)
    plot(abs(u),'b');
    title('Input Pulse'); xlabel('Time'); ylabel('Amplitude');
    hold on
    grid on
    E1_omega=fft(fftshift(u));
    disp(E1_omega)

    %second electric field envelop in fourier space
    P1=9;
    A1=sqrt(P1);
    C=0;
    %pi=3.1415926535;
    % x =-60*10^-15:1*10^-15:59*10^-15
    i=sqrt(-1);
    Wo=120*10^-15;%initial pulse width in second
    u=A1*exp(-(x./Wo).^2)
    figure(2)
    plot(abs(u),'b');
    title('Input Pulse'); xlabel('Time'); ylabel('Amplitude');
    hold on
    grid on
    E2_omega=fft(fftshift(u));
    disp(E2_omega)

    %  patching of the E1 and E2 electric fields with:
    E_omega=[E1_omega,E2_omega]
    disp(E_omega)
    figure(3)
    plot(abs(E_omega),'r');

    zspan=[0 30*10^-3]
    E_omega_0=[0 0.0625]
    [z, E_omega] = ode45(@odefun,zspan,E_omega);

    E1_omega = E_omega(:, 1:end/2);
    E2_omega = E_omega(:, end/2+1:end);
    E1_t = ifft(E1_omega, [], 2);
    E2_t = ifft(E2_omega, [], 2);

    figure(101)
    subplot(2, 2, 1)
    [X, Y] = meshgrid(1:size(E1_omega, 2), z);
    mesh(X, Y, abs(fftshift(E1_omega, 2)).^2);
    subplot(2, 2, 2)
    [X, Y] = meshgrid(1:size(E1_omega, 2), z);
    mesh(X, Y,abs(fftshift(E2_omega, 2)).^2);
    subplot(2, 2, 3)
    [X, Y] = meshgrid(x, z);
    mesh(X, Y,abs(fftshift(E1_t, 2)).^2);
    subplot(2, 2, 4)
    [X, Y] = meshgrid(x, z);
    mesh(X, Y,abs(fftshift(E2_t, 2)).^2);

    % g=angle(E_omega) 
    %  K=unwrap(g)
    figure(4)
     plot(z,E_omega,'linewidth',4)
        xlabel('z')
       ylabel('phase (radian)')
       toc

    function dE_omega_dz = odefun(z, E_omega,~,~)
    dE_omega_dz=zeros(length(E_omega),1);

    Dk=20.94;
    l=800;        % lambda 800nm
    c=3*10^8;
    pi=3.1415926535;
    omega=2*pi*c/l;
    n_2=5*10^-16;   %5*10^-16cm^2/W
    L_NL=3.7245*10^-3;
    LGVM=0.6*10^-3;

    I0=50*10^9;

    to=125e-12; % initial pulse widthin second
    dt=1e-12/to;

    dw=1/l/dt*2*pi;
    w=(-1*l/2:1:l/2-1)*dw;

    % you would have to split the fields back in two:
    E1_omega = E_omega(1:end/2);
    E2_omega = E_omega(end/2+1:end);

    % go back to time space to calculate the nonlinear part:
    E1_t = ifft(E1_omega);
    E2_t = ifft(E2_omega);

    % and calculate the derivatives:
    dE_omega_dz(1:length(E_omega)/2) = fft(1i*conj(E1_t).*E2_t.*exp(1i*Dk*z) ...
        + 1i*2*pi*n_2*I0*L_NL/l*(abs(E1_t.^2 + ...
        2*abs(E2_t.^2)).*E1_t));
    dE_omega_dz(length(E_omega)/2+1:length(E_omega)) = 1i*omega*L_NL/LGVM * E2_t + fft(1i*E1_t.*E1_t.*exp(-1i*Dk*z)....
        + 1i*4*pi*n_2*I0*L_NL/l*(2*abs(E1_t.^2 + ...
        abs(E2_t.^2)).*E1_t));

    end

%    l=max(size(u))
%    fwhm1=find(abs(u)>abs(max(u)/2));
% fwhm1=length(fwhm1)
% WWo=(1.699*fwhm1)/2
%    max(u)
%    dw=1/l/dt*2*pi;
% w=(-1*l/2:1:l/2-1)*dw;
%
% u=fftshift(u)
%  w=fftshift(w)
% spectrum=fft(fftshift(u))
%
% spectrum=spectrum.*exp(-i*w.^2*1.064*10^-6*(h/2*pi))
% f=(ifft((spectrum)));
%
% [t,y]=ode45(@amplitude1,[0 1],[1 1 0]);
% k=1
% y4=y(k)
% k=k+1
% f=f*(-2.02771279053773 + 6.08080900963716i);
% spectrum=fftshift((fft(fftshift((f)))));
% spectrum=spectrum.*exp(-i*w.^2*1.064*10^-6*(h/2*pi));
% f=ifftshift(ifft(ifftshift((((spectrum))))));
% J=max(abs(f))
% j=j+1
% Po(j)=J
%
%
%
%
% plot(abs(f),'r')
% %
%
% fwhm=find(abs(f)>abs(max(f)/2))
% fwhm=length(fwhm)
% s=s+1
% Wo(s)=(1.699*fwhm)/2
% ratio=fwhm/fwhm1
%

% clc
% clear all
% close all
% i=sqrt(-1);
% alph=0
% ln=1
% Po=64;
% alpha=0; % Fiber loss value in dB/km
% alph=alpha/(4.343); %Ref page#55 eqn 2.5.3 Fiber optic Comm by GP Agrawal
% gamma=0.003; %fiber non linearity in /W/m
% to=20; %initial pulse width in second
% pi=3.1415926535;
% Ao=sqrt(Po); %Amplitude
% %----------------------------------------------------------
% x =- 30:1:29;%  dt=t/to
%  dt=1/20;
%  k=1
%  h=0.0077519379844961;% step size
%  %the various fiber lengths can be varied and this vector can be changed
%
%     u=Ao*exp(-(x/to).^2);%page#47 G.P.AGrawal
%     figure(1)
% %    plot(abs(u),'r');
%    title('Input Pulse'); xlabel('Time'); ylabel('Amplitude');
% grid on;
% hold on;
% l=max(size(u));
% %%%%%%%%%%%%%%%%%%%%%%%
% fwhm1=find(abs(u)>abs(max(u)/2));
% fwhm1=length(fwhm1);
% dw=1/l/dt*2*pi;
% w1=(-1*l/2:1:l/2-1)*dw
% u=fftshift(u);
%  w=fftshift(w1)
% spectrum=fft(fftshift(u)); %Pulse spectrum
%  q=h:h:1
% spectrum=spectrum.*exp(-i*1.064*w.^2*(h/4*2*pi));
% f=ifft(spectrum);
%
% [t,y]=ode45(@amplitude1,[0 1],[1 1 0]);
%
% y4=y(k)
% k=k+1
% f=f.*exp(0.335545781012448 + 0.321505706629338i);
% spectrum=fft(f);
% spectrum=spectrum.*exp(-i*1.064*w.^2*(h/4*2*pi)) ;
%
% f=ifft(spectrum);
%
% % op_pulse(ln,:)=abs(f);%saving output pulse at all intervals
% fwhm=find(abs(f)>abs(max(f)/2));
% fwhm=length(fwhm);
% ratio=fwhm/fwhm1 %PBR at every value
% % pbratio(ln)=ratio;%saving PBR at every step size
% % dd=atand((abs(imag(f)))/(abs(real(f))));
% % phadisp(ln)=dd;%saving pulse phase
% % ln=ln+1;
% %
%
% plot(abs(f),'b')

[Adam]

You haven't actually asked a question, nor indeed any words at all!

https://uk.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

https://uk.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup#answer_18099

[asim asrar]

MY CODE IS GIVING ERROR AS Error using horzcat Requested 240x1094476 (3.9GB) array exceeds maximum array size preference. Creation of arrays greater than this limit may take a long time and cause MATLAB to become unresponsive. See array size limit or preference panel for more information.

Error in ode45 (line 484) yout = [yout, zeros(neq,chunk,dataType)];

Error in odefun2 (line 54) [z, E_omega] = ode45(@odefun,zspan,E_omega);

I HAVE TRIED SOLVING TWO COUPLED DIFFERENTIAL EQUATION USING FFT AND ODE45 , BUT FOR CERTAIN VALUE OF DATA ITS GOING BEYOND THE DIMENSIONAL LIMITS , PLEASE HELP ME RESOLVE THIS

[Adam]

Well, unless there is a mistake in your code, that is making your data bigger than it should be, you either need to use less data or get more memory. I'm not familiar with whatever it is your code does so am not going to spot any instructions that accidentally make your arrays bigger than they should be, if there are any such instructions.