Warning: Rank deficient, rank = 0... means what?
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Rick
el 25 de Sept. de 2012
Comentada: Brandon Sackett
el 18 de Nov. de 2020
Hi,
I am using the original signal FS and nbits. When i played the sound, it does have the speech, but its very noisy. I am currently doing this:
wavwrite(sig, Fs, nbits, 'Scrambled.wav');
i = 1;
k = 1;
siz = wavread('Scrambled.wav', 'size');
tot_samples = siz(1);
while(i<=tot_samples-15)
y = wavread('Scrambled.wav',[i i+15]);
ori_sig(:,k) = y\H;
if i == 1;
disp('Descrambling Speech in Progress...');
end
i = i+16;
k = k+1;
end
recon_sig = reshape(ori_sig,size(ori_sig,1)*size(ori_sig,2),1);
sound(recon_sig);
I have this warning: "Warning: Rank deficient, rank = 0, tol = 0.000000e+00."
What does it mean?
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Respuesta aceptada
Wayne King
el 25 de Sept. de 2012
Editada: Wayne King
el 25 de Sept. de 2012
The inverse of a NxN matrix only exists only if the matrix has rank N. In other words, the linear operator that the matrix represents is surjective.
Computing the inverse in a computer has numerical subtleties. That warning is telling you that the matrix is rank deficient.
The wavwrite warning indicates that your signal values exceed +/- 1 and are being clipped when the .wav file is written. I don't think you want that clipping, that distorts the signal. You can scale the vector in MATLAB to make sure that the values do not exceed +/- 1 for writing.
6 comentarios
Brandon Sackett
el 18 de Nov. de 2020
Isn't a surjective solution valid though? I guess bijections are the "best" but is there a reason a surjective solution gets that warning? Any relation to group theory would help my brain understand the problem.
Más respuestas (1)
Walter Roberson
el 25 de Sept. de 2012
I can't tell what your "H" is there, but your "y" is all zero (or close to it) for 16 consecutive samples at some point.
The "clipped" indicates that you are attempting to write samples outside the range -1 to +1.
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