dividing out smaller matrices bracketed by columns of just 0's

I have a 16 high by 200 wide matrix of somewhat random 0's and 1's. I'm trying to section off smaller matrices..of columns that each contain at least one 1, which are bracketed by columns of pure 0's. So for 001101110010, assuming theres just one row, there would be 3 smaller matrices of 2, 3, and 1 columns. And then I was hoping to count all the ones in each respective matrix. Any ideas?

Thank you

[Sean de Wolski]

So for this you would want the sum of the number of ones in columns 3,4 as one value, 678 as a seconf etc? This would be a good CODY problem.

Answer 1

[Walter Roberson]

t = any(YourMatrix,1);
fc = strfind(t, [0 1]) + 1;
lc = strfind(t, [1 0]);

Then each pair fc(K), lc(K) gives the columns to sum submatrix #K over.

You may wish to consider making the above logic more robust to take into account the possibility that a submatrix starts at the very beginning of YourMatrix or ends at the very end of YourMatrix.

[Brandon]

Thank you. So how would you enable MATLAB to automatically input the fc and lc ends and sum those matrices? so that I could reproduce this and not have to manually enter it?

Thanks again, I really appreciate the help

Answer 2

[Sean de Wolski]

One of many ways:

x = [0 1 1 0 1 0 1 1 1;ones(1,9)]; %sample

dcdr = diff([0 x(1,:) 0]); %1st deriv
blow = find(dcdr==1); %low bound
bup  = find(dcdr==-1)-1;  %high bound
xs = sum(x); %columns sums
for ii = numel(bup):-1:1
    S(ii) = sum(xs(blow(ii):bup(ii))); %each one
end

[Brandon]

How do you get this to apply to all 16 rows?