Why does this code give error?

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Sadiq Akbar 2024-4-16

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2107251-why-does-this-code-give-error

评论： Sadiq Akbar 2024-4-22

clear;clc
%%  
fc = 3e8;% Carrier frequency
Nb = 1000;% Number of snapshots
c = 3e8;
wavelength = c/fc;% The wavelength of the received signal 
d = 0.5*wavelength; 
theta = [5 40];
M = length(theta);% Number of signals
N = 10;% Number of antennas
% Wavenumber
beta = 2*pi/wavelength;
% Signal amplitude
A = 1;   
% SNR (dB)
snr = 5;    
% Variance of noise
sigma=sqrt((A^2)/(2*10^(snr/10)));
% Source signal 
D = randi(M,Nb,1);
S =A*(2*D - 1);
% The electrical phase shift from element to element along the array
phi=beta*d*cos(theta*pi/180);  
% Matrix of steering vectors
for i=1:M
  for k=1:N;
    VecteurDirectionnel(k,i)= exp(j*(k-1)*phi(i));
  end
end
% White Gaussien noise
B = (sigma^2)*(randn(N,Nb)+j*randn(N,Nb))/sqrt(2);
% Array output:signal plus noise
X = VecteurDirectionnel*S+B;
Error using *
Incorrect dimensions for matrix multiplication. Check that the number of columns in the first matrix matches the number of rows in the second matrix. To operate on each element of the matrix individually, use TIMES (.*) for elementwise multiplication.
% Estimation of the spatial correlation matrix of the observed signal
Rxx = X*X'/Nb;
% Eigen decomposition
[Vi,Li] = eig(Rxx);
[L,I] = sort(diag(Li),'descend');
V = Vi(:,I);
Vs = V(:,1:M);
Vs1=Vs(1:N-1,:);
Vs2=Vs(2:N,:);
% Direction Of Arrival
% Least square
xsi=linsolve(Vs(1:N-1,:),Vs(2:N,:));
% DOA estimation
doa=acosd((angle(eig(xsi))/(2*pi*d)))

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Answer 1

Matt J 2024-4-16

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2107251-why-does-this-code-give-error#answer_1441796

编辑：Matt J 2024-4-16

在 MATLAB Online 中打开

As you can see, VecteurDirectionnel and S are the wrong sizes for matrix multiplication,

whos VecteurDirectionnel S
  Name                        Size            Bytes  Class     Attributes

  S                        1000x1              8000  double              
  VecteurDirectionnel        10x2               320  double    complex   
% Array output:signal plus noise
X = VecteurDirectionnel*S+B;
Error using *
Incorrect dimensions for matrix multiplication. Check that the number of columns in the first matrix matches the number of rows in the second matrix. To operate on each element of the matrix individually, use TIMES (.*) for elementwise multiplication.