To Run A For-Loop

Hi,

Here is a coding where fx1 to fx16 is varying in steps of 2 and fy1 to fy16 is constant(2). Can anyone help me in writing the frequency from first row to fourth row using ' for-loop' so that it gives the same pattern as it is giving now.

The Code:

    % Frequency Of The First Row

      fx1=2;fy1=2;
      fx2=4;fy2=2;
      fx3=6;fy3=2;
      fx4=8;fy4=2;

    % Frequency Of The Second Row

    fx5=10;fy5=2;
    fx6=12;fy6=2;
    fx7=14;fy7=2;
    fx8=16;fy8=2;

    % Frequency Of The Third Row

    fx9=18;fy9=2;
    fx10=20;fy10=2;
    fx11=22;fy11=2;
    fx12=24;fy12=2;

    % Frequency Of The Fourth Row

      fx13=26;fy13=2;
      fx14=28;fy14=2;
      fx15=30;fy15=2;
      fx16=32;fy16=2;

    M=zeros(512);
    a=128;
    b=128;
    [x,y]=meshgrid(-1:2/127:+1, -1:2/127:+1);
    circ=sqrt(x.^2+y.^2)<1;

    % Generation Of Holograms

    h1=circ.*(cos((x*pi*fx1)+(y*pi*fy1)))>0;
    h2=circ.*(cos((x*pi*fx2)+(y*pi*fy2)))>0;
    h3=circ.*(cos((x*pi*fx3)+(y*pi*fy3)))>0;
    h4=circ.*(cos((x*pi*fx4)+(y*pi*fy4)))>0;

    h5=circ.*(cos((x*pi*fx5)+(y*pi*fy5)))>0;
    h6=circ.*(cos((x*pi*fx6)+(y*pi*fy6)))>0;
    h7=circ.*(cos((x*pi*fx7)+(y*pi*fy7)))>0;
    h8=circ.*(cos((x*pi*fx8)+(y*pi*fy8)))>0;

    h9=circ.*(cos((x*pi*fx9)+(y*pi*fy9)))>0;
    h10=circ.*(cos((x*pi*fx10)+(y*pi*fy10)))>0;
    h11=circ.*(cos((x*pi*fx11)+(y*pi*fy11)))>0;
    h12=circ.*(cos((x*pi*fx12)+(y*pi*fy12)))>0;

    h13=circ.*(cos((x*pi*fx13)+(y*pi*fy13)))>0;
    h14=circ.*(cos((x*pi*fx14)+(y*pi*fy14)))>0;
    h15=circ.*(cos((x*pi*fx15)+(y*pi*fy15)))>0;
    h16=circ.*(cos((x*pi*fx16)+(y*pi*fy16)))>0;

    % An Array Of 4x4 Holograms(Concatenation)
    % First Row Of Holograms
    M(1:a, 1:b) = h1; %M(1, 1)
    M(1:a, b+1:b*2) = h2; %M(2, 1)
    M(1:a, 2*b+1:b*3) = h3; %M(3, 1) 
    M(1:a, 3*b+1:b*4) = h4; %M(4, 1)

    % Second Row Of Holograms
    M(a+1:a*2, 1:b) = h5;%M(1, 2) 
    M(a+1:a*2, b+1:b*2) = h6; %M(2, 2) 
    M(a+1:a*2, 2*b+1:b*3) = h7; %M(3, 2) 
    M(a+1:a*2, 3*b+1:b*4) = h8; %M(4, 2)

    % Third Row Of Holograms
    M(2*a+1:a*3, 1:b) = h9; %M(1, 3)
    M(2*a+1:a*3, b+1:b*2) = h10; %M(2, 3)
    M(2*a+1:a*3, 2*b+1:b*3) = h11; %M(3, 3) 
    M(2*a+1:a*3, 3*b+1:b*4) = h12; %M(4, 3) 

    % Fourth Row Of Holograms
    M(3*a+1:a*4, 1:b) = h13; %M(1, 4)
    M(3*a+1:a*4, b+1:b*2) = h14; %M(2, 4)
    M(3*a+1:a*4, 2*b+1:b*3) = h15; %M(3, 4)
    M(3*a+1:a*4, 3*b+1:b*4) = h16; %M(4, 4)

    figure(1) 
    imagesc(M),colormap gray; axis image; axis off 
    title('Array Of 4x4 Holograms');

    %Fourier Transform
    z=fftshift(fft2(M,512,512));
    q=abs(z);

    figure(2)
    imagesc(q); colormap gray; axis image; axis off
    title('Focal Spots Of Grating Array');

Answer 1

[Andrei Bobrov]

Please try code:

fx = 2:2:2^5;
fy = 2;
a=128;
b=128;
[x,y] = meshgrid(linspace(-1,1,128));
circ=sqrt(x.^2+y.^2)<1;
h = bsxfun(@times,circ,cos(pi*bsxfun(@plus,bsxfun(@times,x,reshape(fx,1,1,[])),fy*y)))>0;
n = size(h);
M = cell2mat(reshape(mat2cell(h,n(1),n(2),ones(n(3),1)),4,[]))';
figure(1) 
imagesc(M),colormap gray; axis image; axis off 
title('Array Of 4x4 Holograms');    %Fourier Transform
z=fftshift(fft2(M,512,512));
q=abs(z);    figure(2)
imagesc(q); colormap gray; axis image; axis off
title('Focal Spots Of Grating Array');

OR with loop 'for..end'

fx = 2:2:2^5;
fy = 2;
a=128;
b=128;
c=512;
[x,y] = meshgrid(linspace(-1,1,128));
circ=sqrt(x.^2+y.^2)<1;
for j1 = numel(fx):-1:1
    h{j1} = circ.*cos(pi*(x*fx(j1) + y*fy));
end
M = cell(c/a);
M(:) = h;
M = cell2mat(M');
figure(1) 
imagesc(M),colormap gray; axis image; axis off 
title('Array Of 4x4 Holograms');    %Fourier Transform
z=fftshift(fft2(M,512,512));
q=abs(z);    figure(2)
imagesc(q); colormap gray; axis image; axis off
title('Focal Spots Of Grating Array');

[Pranjal Pathak]

Thanks a lot sir. It really reduced the size of my code. Once again, thanks!!!