Error using + Matrix dimensions must agree

Error using + Matrix dimensions must agree.

Error in AddWaveform (line 8) tmp=tmp+Wav(((i-1)*2090+x):i*2090);

1   function tmp = AddWaveform(Wav)
2   tmp=zeros(1,2090);
3   for i=1:1244
4       x=1;
5       flag=0;
6       while(flag==0)    
7           if (mod(Wav((i-1)*2090+x),7500)==0)
8               tmp=tmp+Wav(((i-1)*2090+x):i*2090);
9               flag=1;
10           end        
11          x=x+1;
12       end
13   end

my input waveform value is 1x2601900 double

Answer 1

[Image Analyst]

x keeps growing larger and larger until eventually (i-1)*2090+x exceeds 2601900.

[Image Analyst]

By the way, this will help immensely: http://blogs.mathworks.com/videos/2012/07/03/debugging-in-matlab/

[sam]

I see, thanks for the answer Image.

However, in my case, it's not possible for x to exceed 2601900, because it will definitely flag before that. Why is this not a warning, but an error?

How do you think I should fix this?

[Image Analyst]

When it fails, one of the indexes is too big. Try a function like this:

function tmp = AddWaveform(Wav)
try
  tmp=zeros(1,2090);
  for i=1:1244
    x=1;
    flag=0;
    while(flag==0)
      if (mod(Wav((i-1)*2090+x),7500)==0)
        index1 = ((i-1)*2090+x);
        index2 = i*2090;
        tmp=tmp+Wav(((i-1)*2090+x):i*2090);
        flag=1;
      end
      x=x+1;
    end
  end
catch ME
  errorMessage = sprintf('Error in AddWaveform().\nThe error reported by MATLAB is:\n\n%s', ME.message);
  uiwait(warndlg((errorMessage));
end

Set a breakpoint in the catch block on the uiwait() statement, and see what index1 and index2 are when it stops there. And see what (i-1)*2090+x evaluates to. One of them will be too big.

[sam]

-Image,

thanks so much. It was that with my current code, Wav(((i-1)*2090+x):i*2090) was not the same size as tmp.

I only figured it out when I viewed the difference between Index1 and Index2. So basically, I was trying to loop and add a different sized matrix each time.

thanks again!