subscript indices must either be real positive integers or logicals( X_re(k_r)=XD(1,kd); can anyone help me why i am getting this error

clc clear all N=1024; tic; k=50; d=28; aa=6; b=10; a=3; X=zeros(1,N); % xp_unsolved2=[]; % X_p=randperm(N,k); % X_v1=rand(1,k); % X_v=aa*X_v1+b; % X(X_p)=X_v; sss=[0,1,2,3,4,5,6]; ss=[0,1,2,3];

for snr_num=1:9; snr=snr_num*5+0; for exp_num=1:100; % X=zeros(1,N); X_p=randperm(N,k); X_v1=rand(1,k); X_v=aa*X_v1+b; X(X_p)=X_v; % X_v=[aa+b]; X_re=zeros(1,N); x0=ifft((X));

 x=awgn(x0,snr,'measured') ;  
 enerx=sum(x.^2);
energy=abs(sum(x0.^2));
noise=sum((x-x0).^2);
db=10*log10(abs(enerx/noise));

Len=length(x); x1=0.3*(b/d)^2; x2=0.151; x3=4; X4=8; ssss=6; ss=[0,1,2,3]; for l=0:2*a-1; xd(l,:)=downsample(x(ss(l)+1:Len),d); XD(l,:)=fft(xd(l,:)); end % for l=0:2*a-1 % xd(l+1,:)=downsample(x(1+l:Len),d); % % end % D_len=size(xd,2); % d1=2*d; % XD=fft(xd,D_len,2)*d;

xp_unsolved2=[];

k_zeros=[]; k_two=[]; k_1=[]; kk=0; kk1=0; num_1=0; num_2=0; for kd=1:N/d;

    if XD(1,kd).^2 < x1;
      k_zeros=[k_zeros,kd+N/d];

    else
        if abs(abs(XD(1,kd).^2)-abs(XD(2,kd).^2)) <x2;
%            if abs(XD(1,kd).^2)-(XD(2,kd).^2) <x2; 
           k_1 =[];
           num_1=num_1+1;
            for hhh=1:d
                 k_1=[k_1,kd+(hhh-1)*N/d];
            end
            kkk_1(num_1,:)=k_1;
           phase= mod(angle(XD(2,kd)/XD(1,kd)),2*pi);
              k_estim=phase*N/2/pi+1;
              k_com=k_1-k_estim;
             [value,posn]=min(abs(k_com));
             k_r=k_1(posn);
             X_re(k_r)=XD(1,kd);

[Adam]

Simplest way to solve this is just to use the debugger when it should become obvious. Without formatting your code correctly it is very difficult to see easily where your indices are coming from for your arrays.

k_r appears to be the result of a chain of operations which is hard to verify if it is a positive integer or logical or not.

Answer 1

[Adam]

At a glance N/d is 1024 / 28 which is not an integer so I imagine

k_1=[k_1,kd+(hhh-1)*N/d];

produces non-integer values and you then use results from this array to index into another array.