what's wrong here?

Question

Monali 2015-1-11

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https://ww2.mathworks.cn/matlabcentral/answers/169542-what-s-wrong-here

评论： Monali 2015-2-28

采纳的回答： Image Analyst

在 MATLAB Online 中打开

gamma1(i)=gamma(i-1)*lambda*epf(i-1)/epf(i)

here the error showing is that

" Invalid syntax at'='. Possibly a ),},or ] is missing"

rectify what is the mistake here and how to correct it?

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Answer 1

Image Analyst 2015-1-11

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There is nothing wrong with that code. Please tell us the entire error message, not a small part of it like you did. What you showed is not a MATLAB error message. How do I know? Well it doesn't have line numbers or function names for one thing. Also tell us the value of i when it errors. With syntax errors, it's possible that the error actually starts on the line before what it says.

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Monali 2015-1-11

在 MATLAB Online 中打开

 gamma1(i)=gamma(i-1)*lambda*epf(i-1)/epf(i);
          |
Error: The expression to the left of the equals sign is not a valid target for an assignment.
 The code is:
M=25; N=1000; Delay=3; lambda=1;
noise=randn(N,1);
noise1=filter([zeros(1,Delay)],1,noise);
[Num,Den]=butter(10,0.5);
noise1=filter(Num,Den,noise);
noise1=noise1/std(noise1)*0.5;
weights=zeros(M,length(noise1)+1);
d=signal+noise1;
%INITIALIZATION
epsilon=0.00001;
w=zeros(M,N);
uvec=zeros(1,M);
e=zeros(N,1);
wf(1:M,1)=0;
wb(1:M,1)=0;
w(1:M,1)=0;
phi(1:M,1)=0;
gamma(1)=1;
epb(1:M,1)=epsilon;
epf(1:M,1)=epsilon;
%Filtering Algorithm
for i=2:length(noise1)
%Forward A Priori Prediction Error
efa(i)=noise(i)-uvec*wf(:,i-1);
%Forward A Posterior Prediction Error
ef(i)=efa(i)*gamma(i-1);
%MWLS Forward Error
epf(i)=lambda*epf(i-1)+efa(i)*(ef(i))';
%Forward Weight Update
wf(:,i)=wf(:,i-1)+phi(:,i-1)*ef(i);
phi1(:,i)=[0;phi(:,i-1)+efa(i)'/(lambda*epf(i-1))*[1;wf(:,i-1)];
%M+1 Conversion Factor
gamma1(i)= gamma(i-1)*lambda*epf(i-1)/epf(i);
%Backward A Priori Prediction Error
eba(i)=lambda*epb(i-1)*phi1(M+1,i);
gammainv=1/gamma1(i)-phi1(M+1,i)*eba(i);
gamma(i)=1/gammainv;
eb(i)=eba(i)*gamma(i);
epb(i)=lambda*epb(i-1)+eb(i)*eba(i)';
newvec=phi1(:,i)-phi1(M+1,i)*[-wb(:,i-1);1];
phi(:,i)=newvec(1:M);
wb(:,i)=wb(:,i-1)+phi(:,1)*eb(i);
uvec=[noise(i)uvec(1:M-1)];
ea(i)=d(i)-uvec*w(:,i-1);
e(i)=ea(i)*gamma(i);
w(:,1)=w(:,i-1)+e(i)*phi(:,1);
end
The error comes at line 36.. how to correct it?

Monali 2015-1-11

编辑：Star Strider 2015-1-11

在 MATLAB Online 中打开

M=25; N=1000; Delay=3; lambda=1;
n = (1:N);
signal=sin(0.075*pi*n);
noise=randn(N,1);
noise1=filter([zeros(1,Delay)],1,noise);
[Num,Den]=butter(10,0.5);
noise1=filter(Num,Den,noise);
noise1=noise1/std(noise1)*0.5;
weights=zeros(M,length(noise1)+1);
d=signal+noise1;
%INITIALIZATION
epsilon=0.00001;
w=zeros(M,N);
uvec=zeros(1,M);
e=zeros(N,1);
wf(1:M,1)=0;
wb(1:M,1)=0;
w(1:M,1)=0;
phi(1:M,1)=0;
gamma(1)=1;
epb(1:M,1)=epsilon;
epf(1:M,1)=epsilon;
%Filtering Algorithm
for i=2:length(noise1)
%Forward A Priori Prediction Error
efa(i) = zeros(1,100000); 
efa(i)=noise(i)-uvec*wf(:,i-1);
%Forward A Posterior Prediction Error
ef(i)=efa(i)*gamma(i-1);
%MWLS Forward Error
epf(i)=lambda*epf(i-1)+efa(i)*(ef(i))';
%Forward Weight Update
wf(:,i)=wf(:,i-1)+phi(:,i-1)*ef(i);
phi1(:,i)=[0;phi(:,i-1)+efa(i)]/(lambda*epf(i-1))*[1;wf(:,i-1)];
%M+1 Conversion Factor
gamma1(i)= gamma(i-1)*lambda*epf(i-1)/epf(i);
%Backward A Priori Prediction Error
eba(i)=lambda*epb(i-1)*phi1(M+1,i);
gammainv=1/gamma1(i)-phi1(M+1,i)*eba(i);
gamma(i)=1/gammainv;
eb(i)=eba(i)*gamma(i);
epb(i)=lambda*epb(i-1)+eb(i)*eba(i)';
newvec=phi1(:,i)-phi1(M+1,i)*[-wb(:,i-1);1];
phi(:,i)=newvec(1:M);
wb(:,i)=wb(:,i-1)+phi(:,1)*eb(i);
uvec=[noise(i),uvec(1:M-1)];
ea(i)=d(i)-uvec*w(:,i-1);
e(i)=ea(i)*gamma(i);
w(:,1)=w(:,i-1)+e(i)*phi(:,1);
end

The error message is:

Error using  + 
Matrix dimensions must agree.

What to do now?

Image Analyst 2015-1-11

Wow, third error that you're trying to fix via back and forth forum messages. It's really time for you to read this: http://blogs.mathworks.com/videos/2012/07/03/debugging-in-matlab/ so that you can solve problems yourself much, much faster than asking us.

Monali 2015-2-28

Thank you

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Answer 2

John D'Errico 2015-1-11

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https://ww2.mathworks.cn/matlabcentral/answers/169542-what-s-wrong-here#answer_164577

编辑：John D'Errico 2015-1-11

There is absolutely NOTHING wrong with THAT line of code. However...

This kind of error usually indicates you might find an error in a previous line. This is my guess. You have gotten the parser, let me say, confused. It thinks it sees an error in that line, but you are missing a paren or bracket in one of the lines that came before. So when that bracket was missing, it thinks the line was continued onto the next line or so. Then it sees something it cannot understand in context of a continued line, so it gets upset. But it reports an error on the wrong line!

Yes, I know this is sort of a feature. Hey, some would call it a bug. Once you learn what is happening when you see an error like that, you know what to look for, and WHERE to look.

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