why I'm not getting any output here and what should I do in my program?

clear
clc

lambda=1064*1E-9;
k = 2*pi/lambda;

Lx = 0.00864;
screen_rad = Lx/2;
pixel=Lx/1080;

Xline=-screen_rad:pixel:screen_rad-pixel;
Yline=-screen_rad:pixel:screen_rad-pixel;

dim_screen=2*screen_rad;
[X,Y]=meshgrid(Xline,Yline);
r=sqrt(X.^2 + Y.^2);
phi=atan2(Y,X);

ph = ones(1,20).*(1);

N=20;
wd=15*pixel; 
m=1; 
d=6.5*wd;
a=d/sqrt(2*(1-cos(2*pi/N))); % Radius
E=zeros(size(X));
inphase=0;
for j=1:N
   
    theta(j) = pi*(2*(j)-1)/N;
   
    alpha(j) = a*cos(theta(j));
    beta(j)  = a*sin(theta(j));
   
    num = ((X - alpha(j)).^2  +  (Y - beta(j)).^2);
    den = 2*(wd^2);
     E = E + exp(-num./den).*((cos(ph(j))+1i*sin((ph(j))))); % Discrete vortexexp(1i*ph(j));
     
end

H1 = cos(ph);
H2 = sin(ph);

figure(1)
% I think it's due to gradient, then what shoul I use to get arrows at a
% single direction
DEx = gradient(H1);
DEy = gradient(H2);



quiver(H1,H2,DEx,DEy,"LineWidth",1,"Color",'k')

function phaseRGB=phaseRGBconverter(I)
res=360;
A=hsv(res);
phase=ceil((res-1)*(0.5+angle(I)/(2*pi)));
phase(phase==0)=res;
NUn=(abs(I))./max(abs(I(:)));
phaseRGB(:,:,1)=reshape(A(phase,1),size(phase)).*(NUn);%+(1-NUn)/4;
phaseRGB(:,:,2)=reshape(A(phase,2),size(phase)).*(NUn);%+(1-NUn)/4;
phaseRGB(:,:,3)=reshape(A(phase,3),size(phase)).*(NUn);%+(1-NUn)/4;
end

Answer 1

[Image Analyst]

ph is all zeros. That mistake is the source of all your problems.

[SAHIL SAHOO]

now I make ph is 1 still no graph