program going beyond matrix dimension

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asim asrar
asim asrar 2018-9-28
评论： Adam 2018-10-1
%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')
  3 个评论
显示 1更早的评论
asim asrar
asim asrar 2018-9-30
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
Adam 2018-10-1
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.

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