why i am getting the error "Index exceeds the number of array elements (1)" in my code? i am getting the error in line 33.

clc
clear variables
close all

segma_N = 10.^-7;
% p_db = 0:5:30; 
% p = 10.^(p_db/10);%power
p = 0.07;
R = 0.5; %Optoelectronic conversion factor 

rng(1);  
I = abs(random('normal',1,2,1,100))*1e-8;

% Processing
%a= 3.99;% Alpha
%b=2; % Beta 

a=[3.99 3.99 3.99 3.5 3.7 3.99]; % Alpha
b=[6 4 2 2 2 2]; % Beta

% nz = zeros(1, length(p_db));
% z = zeros(1, length(p_db));

SNR = 0:2:30;
SNR_db = 10.^(SNR/10);
nz = zeros(1, length(SNR_db));
z = zeros(1, length(SNR_db));
 
 for k=1:length(a)

    for j = 1:length(z)  
    
     yz =log2(1+((p(j).*R.*I)./segma_N).^2).*zpdf(I,a(k),b(k));
     z(k,j) = trapz(I, yz);   
    
    end

end
      
% Plot
figure
semilogy(SNR_db,nz(1,:),'-ks','MarkerFaceColor','k')
hold on
semilogy(SNR_db,nz(2,:),'-ro','MarkerFaceColor','r')
semilogy(SNR_db,nz(3,:),'-b^','MarkerFaceColor','b')


grid on
xlabel('SNR [dB]')
ylabel('channel Cpacity')
title('Intial Results')
xlim([0 30])

and the function zpdf is

function G = zpdf(I,a,b)

% a: Alpha
% b: Beta

c = 0.2;   %Gamma
%d = 2.6124; %0.8;   %Big omega prime

omega = 1.3265;
b_0 = 0.1079; %Average power of the coupled-to-LOS scattering component
row = 0.55;  %Scattering power coupled to the LOS component
d = (omega+row.*2.*b_0+2.*sqrt(2.*b_0.*omega.*row));%Big omega prime Average optical power of coherent contributions

Aperture_radius = 0.1;   %Aperture_radius
segma_s = 0.2;           %Jitter standard deviation
omega_z =  2.5;          %Beam Width
  
v = (sqrt(pi)*Aperture_radius)/(sqrt(2)*omega_z);

omega_zeq_2 = (omega_z^2)*(sqrt(pi)*erf(v))/(2*v*exp(-(v^2))); 

g = omega_zeq_2/(2*segma_s);

A0 = (erf(v))^2;

A = (2*(a^(a/2))/((c^(1+a/2))*gamma(a)))*(((c*b)/(c*b+d))^(b+a/2));

First = (((g^2)*A)/2)*(I.^-1);

count1 = 0;
for k = 1:b
    
    ak = (nchoosek(b-1,k-1))*(((c*b+d)^(1-k/2))/gamma(k))*((d/c)^(k-1))*((a/b)^(k/2));
    
    Part1 = ak*(a*b/(c*b+d))^(-(a+k)/2);
     
    Part2_1 = (a*b/(c*b+d));
    Part2_2 = I/A0;
    
    Part2 = meijerG([],g^2,[g^2,a,k],[],Part2_1*Part2_2);

    count1 = count1 + Part1.*Part2;
end

G = First.*count1;

end

[Adam Danz]

Make it easy for us to help you have

1) giving us the entire error message

2) telling us which line is causing the error.

We can't run your code due to missing variable values and/or functions.

[Atrolita afra]

yz =log2(1+((p(j).*R.*I)./segma_N).^2).*zpdf(I,a(k),b(k));

i am getting the error in this line saying , "Index exceeds the number of array elements (1)."

[Atrolita afra]

-_- then what is the solution?

Answer 1

[Adam Danz]

From you code,

p = 0.07;

p has 1 value, size (1,1).

In the loop below, when j>1 you're getting the indexing error because p only has 1 value.

 for k=1:length(a)
    for j = 1:length(z)  
    
     yz =log2(1+((p(j).*R.*I)./segma_N).^2).*zpdf(I,a(k),b(k));
     %            ^^^
     z(k,j) = trapz(I, yz);   
    
    end
end

There may be other errors but I'm not going to read through the code to figure that out. If there are more errors, please attach ther data so I can run the code.

[Atrolita afra]

can i do that integration any others way? i have used those loop for integrate the function

[Adam Danz]

p doesn't change. If that's what your intensions are, just remove the indexing for p.