Undefined function or method 'H' for input arguments of type 'double'.

Hi guys.

Why does the following error comes? what is wrong?

??? Undefined function or method 'H' for input arguments of type 'double'.

Error in ==> yeniyazi2FT at 45

H(j)=fftshift(H(j));

close all

clear all

clc

x_1=linspace(-1,1,5);

y_1=linspace(-1,1,5);

z=0.5;

L1=0.5;

lambda=1030e-9;

k=2*pi/lambda;

w0=0.1;

zr=pi*w0.^2/lambda;

R=z*(1+(zr/z).^2);

w=w0*sqrt(1+(z/zr)^2);

[x1,y1]=meshgrid(x_1,x_1);

u1=w0/w.*exp(-(x1.^2+y1.^2).^2/w.^2).*exp(-1i*k*z).*exp(-1i*k*(x1.^2+y1.^2).^2/(2*R));

j=sqrt(-1);

L=0.25;

[M,N]=size(u1); % get inpute field array size

dx=L/M; % sample interval

k=2*pi/lambda; %wavenumber

fx=-1/(2*dx):1/L:1/(2*dx)-1/L; %freq coords

[FX,FY]=meshgrid(fx,fx);

x2=x1; %obs coords

y2=y1;

H=exp(-1i*pi*lambda*z*(FX.^2+FY.^2)); %trans func

for j=1:5

H(j)=fftshift(H(j));

u(j)=fft2(fftshift(u(j)));

u(j+1)=H(j).*u(j);

u(j+1)=ifftshift(ifft2(u(j+1))); end

[Adam]

which is line 45?

Answer 1

[Azzi Abdelmalek]

u is not defined.

x_1=linspace(-1,1,5);
y_1=linspace(-1,1,5);
z=0.5;
L1=0.5;
lambda=1030e-9;
k=2*pi/lambda;
w0=0.1;
zr=pi*w0.^2/lambda;
R=z*(1+(zr/z).^2);
w=w0*sqrt(1+(z/zr)^2);
[x1,y1]=meshgrid(x_1,x_1);
u1=w0/w.*exp(-(x1.^2+y1.^2).^2/w.^2).*exp(-1i*k*z).*exp(-1i*k*(x1.^2+y1.^2).^2/(2*R));
j=sqrt(-1);
L=0.25;
[M,N]=size(u1); % get inpute field array size
dx=L/M; % sample interval
k=2*pi/lambda; %wavenumber
fx=-1/(2*dx):1/L:1/(2*dx)-1/L; %freq coords
[FX,FY]=meshgrid(fx,fx);
x2=x1; %obs coords
y2=y1;
H=exp(-1i*pi*lambda*z*(FX.^2+FY.^2)); %trans func
for j=1:5
  H(j)=fftshift(H(j));
  u(j)=fft2(fftshift(u1(j)));
  u(j+1)=H(j).*u(j);
  u(j+1)=ifftshift(ifft2(u(j+1)));
end

[Habib]

you said: u is not defined.

How can I do it?